Center for Sustainability Science and Strategy

Data associated with the manuscript 'Future nitrogen availability and its effect on carbon sequestration in Northern Eurasia' by Kicklighter et al. (2019)

2019-07-31T00:00:00Z

Data associated with the manuscript 'Future nitrogen availability and its effect on carbon sequestration in Northern Eurasia' by Kicklighter et al. (2019) Kicklighter, David W.; Melillo, Jerry M.; Monier, Erwan; Sokolov, Andrei P; Zhuang, Q. Data used to produce figures in the manuscript 'Future nitrogen availability and its effect on carbon sequestration in Northern Eurasia' by Kicklighter, D., J.M. Melillo, E. Monier, A.P. Sokolov and Q. Zhuang.

Turkish Energy Sector Development and the Paris Agreement Goals: A CGE Model Assessment

2018-07-01T00:00:00Z

Turkish Energy Sector Development and the Paris Agreement Goals: A CGE Model Assessment Kat, Bora; Paltsev, Sergey; Yuan, Mei In the 2015 Paris Agreement, Turkey pledged to reduce greenhouse gas (GHG) emissions by 21% by 2030 relative to business-as-usual (BAU). However, Turkey currently relies heavily on imported energy and fossil-intensive power generation. Despite significant wind and solar energy potential, only 5.1% of its total power is generated by wind and solar installations; additionally, although two nuclear power stations are planned, no nuclear capacity currently exists. We expect that fulfilling Turkey’s Paris Agreement pledge will likely require a reduced reliance on fossil-based energy and additional investments in low-carbon energy sources, which may impact Turkey’s GDP, energy use, and electricity generation profiles. To fully assess these impacts, we develop a computable general equilibrium (CGE) model of the Turkish economy that combines macroeconomic representation of non-electric sectors with a detailed representation of the electricity sector. We analyze several scenarios to assess the impact of an emission trading scheme in Turkey: one including the planned nuclear development and a renewable subsidy scheme (BAU), and in the other with no nuclear technology allowed (NoN). Our assessment shows that in 2030, without policy, primary energy will be mainly oil, natural gas and coal. Under an emission trading scheme, however, coal-fired power generation vanishes by 2030 in both BAU and NoN due to the high cost of carbon. With nuclear (BAU), GHG emissions are 3.1% lower than NoN due to the resulting energy mix, allowing for a lower carbon price ($50/tCO2 in BAU compared to $70/tCO2 in NoN). Our results suggest that fulfillment of Turkey’s Paris Agreement pledge may be possible at a modest economic cost of about 0.8–1% by 2030.

The economic and emissions benefits of engineered wood products in a low-carbon future

2018-06-01T00:00:00Z

The economic and emissions benefits of engineered wood products in a low-carbon future Winchester, Niven Stewart; Reilly, John M There has been rapid growth in the use of engineered wood products in the construction sector in recent decades. We evaluate the economy-wide impacts of replacing carbon-intensive construction inputs, such as steel and cement, with lumber products in the US under an emissions constraint. We find that the ability to substitute lumber-based building materials increases production from the lumber and forestry sectors and decreases production from carbon-intensive sectors such as cement. Under a carbon cap-and-trade policy, the ability to substitute lumber products lowers the carbon price and the GDP cost of meeting the carbon cap, with more overall emissions abatement in the construction industry.

Meeting the Goals of the Paris Agreement: Temperature Implications of the Shell Sky Scenario

2018-04-01T00:00:00Z

Meeting the Goals of the Paris Agreement: Temperature Implications of the Shell Sky Scenario Paltsev, Sergey; Sokolov, Andrei P; Gao, Xiang; Haigh, Martin The Paris Agreement makes long-term energy and climate projections particularly important because it calls for a goal that likely requires an energy system that is based on a radically different fuel mix than currently in use. This presents a challenge for energy companies as they try to anticipate the types of energy and fuels that will be required to stay competitive while meeting environmental requirements. A new scenario (called Sky) developed by Shell International examines the challenge of moving to an energy system with net-zero CO2 emissions and gradually eliminate emissions from deforestation by midway through the second half of the century (specifically by the year of 2070). Using the MIT Integrated Global System Modeling (IGSM) framework, we simulate a 400-member ensemble, reflecting uncertainty in Earth system response of global temperature change associated with the Sky scenario by 2100. We find that for the median climate parameters the global surface temperature increase by 2100 is 1.75°C above the pre-industrial levels with an 85% probability of remaining below 2°C. The geographic distribution of the temperature change shows a stronger warming in Polar regions. If, in addition, there is a significant effort directed toward global reforestation then, with median climate parameters, temperature increase by 2100, is near 1.5°C above pre-industrial levels.

Next Steps in Tax Reform

2018-04-01T00:00:00Z

Next Steps in Tax Reform Jacoby, Henry D; Montgomery, David; Yuan, Mei The GOP tax reform, now adopted as the 2017 Tax Cuts and Jobs Act, was intended to cut business taxes to stimulate investment, lower some personal taxes, eliminate deductions and tax credits to help pay for the tax reductions, and move the U.S. toward a territorial tax system and reduce the shifting of profits abroad by U.S. companies. Some of these objectives have been achieved, but at the cost of perverse incentives and distributional effects, and the threat of a substantial contribution to the fiscal deficit. As a result, corrections are going to be required in future years. Many of the Act’s undesirable features are attributable to the inability of its drafters to come up with sufficient revenue to compensate for the tax reductions. A CO2 tax is explored, as perhaps the only measure that is consistent with the declared principles of the GOP leadership and likely to draw Democratic support, and large enough to make up for the Act’s revenue-losing provisions. We summarize the process that led to the Act and its major failures. Then, applying the MIT U.S. Regional Energy Policy (USREP) model, we show how, when the Act is opened up for repairs, a CO2 tax could help correct its flaws while serving environmental goals.

The Economic, Energy and Emissions Impacts of Climate Policy in South Korea

2018-03-01T00:00:00Z

The Economic, Energy and Emissions Impacts of Climate Policy in South Korea Winchester, Niven Stewart; Reilly, John M Using an economy-wide model, we evaluate the impact of policies to meet South Korea’s Paris pledge to reduce greenhouse gas (GHG) emissions by 37% relative to those under business as usual (BAU) in 2030. Simulated BAU emissions in 2030 are 840.8 million metric tons (Mt) of carbon dioxide equivalent (CO2e), indicating that economy-wide emissions should be constrained to 529.7 MtCO2e. Under South Korea’s Emissions Trading System (KETS) and fuel economy standards, a 2030 carbon price of $89/tCO2e is needed to meet this goal. Without considering benefits from avoided climate damages, these policies reduce 2030 GDP by $20.6 billion (1.0%) and consumer welfare by 7.9 billion (0.7%). Comparing this scenario to one where South Korea’s Paris pledge is met solely by an ETS, indicates that adding a fuel economy standard reduces GDP and welfare by, respectively, $4.2 billion and $1.1 billion. Declines in sectoral production are largest for fossil-based energy sectors and the chemical, rubber and plastic products, and iron and steel sectors.

Evaluating India’s climate targets: the implications of economy-wide and sector specific policies

2018-03-01T00:00:00Z

Evaluating India’s climate targets: the implications of economy-wide and sector specific policies Singh, Arun; Winchester, Niven Stewart; Karplus, Valerie Jean We employ a numerical economy-wide model of India with energy sector detail to simulate the impact of India’s commitments to the Paris Climate Agreement. We simulate targets for reducing CO2 emissions intensity of GDP via an economy-wide CO2 price and for increasing non-fossil electricity capacity via a Renewable Portfolio Standard. We find that compared to the no policy scenario in 2030, the average cost per unit of emissions reduced is lowest under a CO2 pricing regime. Adding an RPS increases the cost by more than ten times. Projected electricity demand in 2030 decreases by 8% under the CO2 price, while introducing an RPS further suppresses electricity demand. Importantly, a reduction in the costs of wind and solar power induced by favorable policies may result in cost convergence across instruments, paving the way for more aggressive decarbonisation policies in the future.

MIT Climate Resilience Planning: Flood Vulnerability Study

2018-03-01T00:00:00Z

MIT Climate Resilience Planning: Flood Vulnerability Study Strzepek, Kenneth; Fant, Charles W; Preston, Matthew; Emanuel, Kerry Andrew; Goldberg, Brian The MIT Flood Vulnerability Study is one key part of a broader initiative led by the MIT Climate Resiliency Committee (CRC) and the MIT Office of Sustainability (MITOS) to understand and recommend how MIT can continue to fulfill its mission in the face of intensifying climate risks over the next 100 years and beyond; risks include precipitation flooding, sea level rise/storm surge and chronic heat stress. This study seeks to translate the science of current flooding risks and future campus-based flooding risk from climate change into operational and strategic guidance for informing campus planning and management. Inspired by the MIT Plan for Action on Climate Change, one key research and academic objective of this study is to utilize the MIT campus as a test bed for climate innovations. This study engages MIT’s global research expertise in downscaling global MIT climate models for application testing on MIT’s campus, and also collaborates with expertise and tools advancing the MIT Sustainable Stormwater and Ecological Landscape Master Plan. This research initiative is supported by the MIT Office of Sustainability in collaboration with the MIT Joint Program on the Science and Policy of Global Change.

Description and Evaluation of the MIT Earth System Model (MESM)

2018-02-01T00:00:00Z

Description and Evaluation of the MIT Earth System Model (MESM) Sokolov, Andrei P; Kicklighter, David W.; Schlosser, C. Adam; Wang, Chien; Monier, Erwan; Brown-Steiner, Benjamin E; Prinn, Ronald G; Forest, Chris E; Gao, Xiang; Libardoni, Alex; Eastham, Sebastian David The MIT Integrated Global System Model (IGSM) is designed for analyzing the global environmental changes that may result from anthropogenic causes, quantifying the uncertainties associated with the projected changes, and assessing the costs and environmental effectiveness of proposed policies to mitigate climate risk. The IGSM consists of the MIT Earth System Model of intermediate complexity (MESM) and the Economic Projections and Policy Analysis (EPPA) model. This paper documents the current version of the MESM, which includes a 2-dimensional (zonally averaged) atmospheric model with interactive chemistry coupled to the Global Land System model and an anomaly-diffusing ocean model.

Finding Itself in the Post-Paris World: Russia in the New Global Energy Landscape

2017-12-01T00:00:00Z

Finding Itself in the Post-Paris World: Russia in the New Global Energy Landscape Makarov, Igor; Chen, Y.-H. Henry; Paltsev, Sergey The Russian budget relies heavily on exports of fossil fuels, which are the major source of greenhouse gas (GHG) emissions. Climate-related policies that target a reduction in GHG emissions affect substantially the Russian economy. We apply the MIT Economic Projection and Policy Analysis (EPPA) model to assess the impacts of the Paris Agreement on the Russian economy and find that climate-related actions outside of Russia lower Russia’s GDP growth rate by about a half of a percentage point. In addition, Russia faces the risks of market barriers for its exports of energy-intensive goods as well as risks of falling behind in development of new energy technologies that become standard in most of the world. In order to address these risks, the country needs a new comprehensive development strategy taking into account the Post-Paris global energy landscape. We offer suggestions for key elements of such a strategy, including diversification of economy, moving to low-carbon energy, and investing in human capital development. We simulate three simple diversification scenarios showing that redistribution of incomes from energy sector to the development of human capital would help avoid the worst possible outcomes.

The Economic Projection and Policy Analysis Model for Taiwan: A Global Computable General Equilibrium Analysis

2017-11-01T00:00:00Z

The Economic Projection and Policy Analysis Model for Taiwan: A Global Computable General Equilibrium Analysis Chai, Hui-Chih; Hong, Wei-Hong; Reilly, John M; Paltsev, Sergey; Chen, Y.-H. Henry We present and evaluate a new global computable general equilibrium (CGE) model to focus on analyzing climate policy implications for Taiwan’s economy and its relationship to important trading partners. The main focus of the paper is a critical evaluation of data and model structure. Specifically, we evaluate the following questions: How do the different reference year data sets affect results of policy simulations? How important are structural and parameter assumptions? Are explicit treatment of trade and international policy important? We find: (1) Higher mitigation costs across regions using data for the year of 2011, as opposed to cases using the 2007 and 2004 data, due to increasing energy cost shares over time. (2) Lower GDP losses across regions under a broad carbon policy using a more complex model structure designed to identify the role of energy and GHG emissions in the economy, because the formulation allows more substitution possibilities than a more simplified production structure. (3) Lower negative impacts on GDP in Taiwan when it carries out its national determined contribution (NDC) as part of a global policy compared with unilateral implementation because, under a global policy, producer prices for fossil fuels are suppressed, benefiting Taiwan’s economy.

Mid-Western U.S. Heavy Summer-Precipitation in Regional and Global Climate Models: The Impact on Model Skill and Consensus Through an Analogue Lens

2017-10-01T00:00:00Z

Mid-Western U.S. Heavy Summer-Precipitation in Regional and Global Climate Models: The Impact on Model Skill and Consensus Through an Analogue Lens Gao, Xiang; Schlosser, C. Adam Regional climate models (RCMs) in general can simulate the characteristics of heavy/extreme precipitation more accurately than general circulation models (GCMs) as a result of more realistic representation of topography and mesoscale processes. An analogue method of statistical downscaling, which identifies the resolved large-scale atmospheric conditions associated with heavy precipitation, is also found to produce more accurate and precise heavy precipitation frequency across a range of GCMs in the Coupled Model Intercomparison Project Phase 5 (CMIP5) than their model-simulated precipitation alone. In this study, we examine the performances of the analogue method versus direct simulation, when applied to the RCM simulations from the North American Regional Climate Change Assessment Program (NARCCAP) and GCM simulations from CMIP5, in detecting present-day and future changes in summer (JJA) heavy precipitation over the Midwestern United States. We find the performances of two analogue schemes are comparable to those of MERRA-2 assimilated and its bias-corrected precipitation in characterizing the occurrence and interannual variations of observed heavy precipitation events, all significantly improving upon MERRA assimilated precipitation. For the late twentieth-century heavy precipitation frequency, RCM precipitation improves upon the corresponding driving GCM from CMIP5 with greater accuracy yet comparable inter-model discrepancies, while both RCM- and GCM-based analogue results outperform their model-simulated precipitation counterparts in terms of accuracy and model consensus. For the projected trends in heavy precipitation frequency through the mid twenty-first century, the analogue method also manifests its superiority to direct simulation with reduced intermodel disparities, while the RCM-based analogue and its simulated precipitation do not demonstrate a salient improvement (in model consensus) over the GCM-based assessment. However, a number of caveats preclude any overall judgement, and further work—over any region of interest—should include a larger sample of GCMs and RCMs as well as ensemble simulations to comprehensively account for modeled internal variability.

New data for representing irrigated agriculture in economy-wide models

2017-10-01T00:00:00Z

New data for representing irrigated agriculture in economy-wide models Ledvina, Kirby J.; Winchester, Niven Stewart; Strzepek, Kenneth; Reilly, John M We develop a framework to represent the value of irrigated crop production and the expansion potential of irrigated land within economy-wide models, providing integrated assessment capabilities for energy, land, and water interactions. Specifically, we compute the value of production on irrigated and rainfed cropland at both a 5 arcminute by 5 arcminute level (about 10 square kilometers) and for the 140 regions and eight crop sectors in Version 9 of the Global Trade Analysis Project (GTAP) Data Base. For each crop category, we estimate the shares of production on irrigated and rainfed land using estimates of production quantities and prices, compared to approximations based on output volumes used in the GTAP-Water Data Base. We construct a global dataset of evaluation metrics to identify region-crop combinations where there are large differences in irrigated production value shares based on direct calculation and approximated by output volumes. The scope to expand the amount of irrigated land and the cost of doing so is quantified through irrigable land supply curves for 126 water regions globally, based on water availability and the costs of irrigation infrastructure. We also make available our adaptable work stream to calculate crop production values and to estimate irrigable land supply elasticities for use in economy-wide models. Altogether, this work can enhance integrated assessment and economy-wide modeling by more accurately capturing the value of crop production and facilitating the representation of endogenous investment in irrigation infrastructure in response to changing water availability. These data and modeling contributions allow for a more rigorous exploration of the regional and global impacts of water availability on land use, energy production, and economic activity.

Data used to produce figures in the manuscript 'Evaluating Simplified Chemical Mechanisms within Present-Day Simulations of CESM Version 1.2 CAM-chem (CAM4): MOZART-4 vs. Reduced Hydrocarbon vs. Super-Fast Chemistry' by Brown-Steiner et al. (2018)

2018-04-27T00:00:00Z

Data used to produce figures in the manuscript 'Evaluating Simplified Chemical Mechanisms within Present-Day Simulations of CESM Version 1.2 CAM-chem (CAM4): MOZART-4 vs. Reduced Hydrocarbon vs. Super-Fast Chemistry' by Brown-Steiner et al. (2018) Brown-Steiner, B.; Selin, N.E.; Prinn, R.; Tilmes, S.; Emmons, L.; Lamarque, J.-F.; Cameron-Smith, P. Data used to produce figures in the manuscript Evaluating Simplified Chemical Mechanisms within Present-Day Simulations of CESM Version 1.2 CAM-chem (CAM4): MOZART-4 vs. Reduced Hydrocarbon vs. Super-Fast Chemistry by Brown-Steiner, B.; Selin, N. E.; Prinn, R.; Tilmes, S.; Emmons, L.; Lamarque, J.-F.; and Cameron-Smith, P.

Data used to produce figures in the manuscript ‘Maximizing Ozone Signals Among Chemical, Meteorological, and Climatological Variability’ by Brown-Steiner et al. (2018)

2018-03-29T00:00:00Z

Data used to produce figures in the manuscript ‘Maximizing Ozone Signals Among Chemical, Meteorological, and Climatological Variability’ by Brown-Steiner et al. (2018) Brown-Steiner, B.; Selin, N.E.; Prinn, R.G.; Monier, E.; Tilmes, S.; Emmons, L.; Garcia-Menendez, F. Data used to produce figures in the manuscript ‘Maximizing Ozone Signals Among Chemical, Meteorological, and Climatological Variability’ by Brown-Steiner, B.; Selin, N. E.; Prinn, R. G.; Monier, E.; Tilmes, S.; Emmons, L.; Garcia-Menendez, F.

Data associated with the paper Sokolov et al. (2018): "Description and Evaluation of the MIT Earth System Model (MESM)"

2018-01-29T00:00:00Z

Data associated with the paper Sokolov et al. (2018): "Description and Evaluation of the MIT Earth System Model (MESM)" Sokolov, A.; Kicklighter, D.; Schlosser, C.A.; Wang, C.; Monier, E.; Brown-Steiner, B.; Prinn, R.; Forest, C.; Gao, X.; Libardoni, A.; Eastham, S. Data used to produce figures in the paper "Description and Evaluation of the MIT Earth System Model (MESM)" by Andrei Sokolov, David Kicklighter, Adam Schlosser, Chien Wang, Erwan Monier, Benjamin Brown-Steiner, Ron Prinn, Chris Forest, Xiang Gao, Alex Libardoni and Sebastian Eastham.

Data associated with the paper Monier, E. et al. (2018) Nat. Commun., doi:10.1038/s41467-018-02984-9

2018-01-25T00:00:00Z

Data associated with the paper Monier, E. et al. (2018) Nat. Commun., doi:10.1038/s41467-018-02984-9 Paltsev, Sergey; Monier, Erwan Data supporting the findings of the study: Monier, E. et al. Toward a consistent modeling framework to assess multi-sectoral climate impacts. Nat. Commun. doi:10.1038/s41467-018-02984-9 (2018).

Probabilistic projections of the future climate for the world and the continental USA

2017-09-01T00:00:00Z

Probabilistic projections of the future climate for the world and the continental USA Sokolov, A.; Gao, X.; Paltsev, S.; Monier, E.; Chen, H.; Kicklighter, D.; Prinn, R.; Reilly, J.; Schlosser, A. In this paper, we study possible impacts of anthropogenic greenhouse gas (GHG) emissions on the 21st century climate on the continental USA using the MIT Integrated Global System Model (IGSM) framework. Climate change simulations use an emissions scenario developed with the IGSM’s Economic Projection and Policy Analysis (EPPA) Model. The scenario represents a global emission path consistent with the current view on the trajectories of technological and economic development. The estimates of possible changes in climate are based on an ensemble of 400 simulations with the IGSM’s MIT Earth System Model (MESM), a model of intermediate complexity. Regional changes over the USA were obtained using statistical downscaling that incorporates results from the simulations with the CMIP5 Atmosphere-Ocean General Circulation Models (AOGCMs). The results show that under the considered emissions scenario, surface air temperature averaged over the continental USA increases by 2.6 to 4.4K by the last decade of the 21st century (90% probability interval) relative to pre-industrial temperatures, compare to 2.3 to 3.4K for the whole globe. Corresponding changes in precipitation are -0.65 to 0.34 mm/day and 0.13 to 0.22 mm/day, respectively. There is significant variation in the geographical distribution of those changes among the ensemble simulations.

Estimating the potential of U.S. urban infrastructure albedo enhancement as climate mitigation in the face of climate variability

2017-09-01T00:00:00Z

Estimating the potential of U.S. urban infrastructure albedo enhancement as climate mitigation in the face of climate variability Xu, L.; Monier, E.; Schlosser, A.; Kirchain, R.; Gregory, J. The climate mitigation potential of U.S. urban infrastructure albedo enhancement is explored using multidecadal regional climate simulations. Increasing albedo from 0.2 to 0.4 results in summer daytime surface temperature decreases of 1.5°C, substantial reductions in health-related heat (50% decrease in days with danger heat advisory) and decreases in energy demand for air conditioning (15% decrease in cooling degree days) over the U.S. urban areas. No significant impact is found outside urban areas. Most regional modeling studies rely on short simulations; here, we use multidecadal simulations to extract the forced signal from the noise of climate variability. Achieving a ±0.5°C margin of error for the projected impacts of urban albedo enhancement at a 95% confidence level entails using at least 5 simulation years. Finally, single-year higher-resolution simulations, requiring the same computing power as the multidecadal coarser-resolution simulations, add little value other than confirming the overall magnitude of our estimates.

A Win-Win Solution to Abate Aviation CO2 Emissions

2017-08-01T00:00:00Z

A Win-Win Solution to Abate Aviation CO2 Emissions Winchester, N. We outline a benchmark carbon dioxide (CO2) intensity system with tradable permits for the aviation industry that will incent in-sector emission abatement opportunities that cost less than the social cost of carbon (SCC). The system sets benchmark emission intensities (CO2 emissions per revenue ton kilometer) by route group and facilitates flexibility in meeting the benchmarks by allowing airlines to sell permits if they operate more efficiently than the benchmarks, and buy permits if they do not meet the benchmarks. The CO2 benchmark system could operate concurrently with existing measures to mitigate aviation CO2 emissions, will reduce the number of offsets needed to achieve carbon-neutral growth, and provide another (optional) lever to address fairness issues in climate regulations. Moreover, by providing a blueprint for other industries to price marginal emissions at the SCC, a CO2 benchmark system could preserve the ‘carbon budget’ for use by high-cost abatement industries such as the aviation industry.

Application of the Analogue Method to Modeling Heat Waves: A Case Study With Power Transformers

2017-08-01T00:00:00Z

Application of the Analogue Method to Modeling Heat Waves: A Case Study With Power Transformers Gao, X.; Schlosser, C.A.; Morgan, E. Large power transformers (LPTs) are critical yet increasingly vulnerable components of the power grid. More frequent and intense heat waves or high temperatures can degrade their operational lifetime and thereby increase the premature failure risk. Without adequate preparedness, a widespread situation would ultimately lead to prolonged grid disruption and incur excessive economic costs. In this study, we investigate the impact of climate warming and corresponding shifts in heat waves on a selected LPT located in the Northeast corridor of the United States. We apply an analogue method, which detects the occurrence of heat waves based on the salient, associated large-scale atmospheric conditions (“composites”), to assess the risk of future change in heat wave occurrence. Compared with the more conventional approach that relies on climate model-simulated daily maximum temperature, the analogue method produces model medians of late twentieth-century heat wave frequency that are more consistent with observation and have stronger inter-model consensus. Under the future climate warming scenarios, multi-model medians of both model daily maximum temperature and the analogue method indicate strong decadal increases in heat wave frequency by the end of the 21st century, but the analogue method improves model consensus considerably. We perform a preliminary assessment on the decrease of transformer lifetime with temperature increase. Future work will focus on using more advanced algorithms to quantify the impact of more frequent heat waves on the transformer’s expected lifetime and associated additional costs. The improved inter-model consensus of the analogue method is viewed as a promising step toward providing actionable information for a more stable, reliable, and environmentally responsible national grid.

The Revenue Implications of a Carbon Tax

2017-07-01T00:00:00Z

The Revenue Implications of a Carbon Tax Yuan, M.; Metcalf, G.E.; Reilly, J.; Paltsev, S. A primary reason for implementing a carbon or greenhouse gas tax is to reduce emissions, but in recent years there has been increased interest in a carbon tax’s revenue potential. This revenue could be used for federal deficit reduction, to help finance tax reform, support new spending priorities such as infrastructure spending, offset the burden of the tax on households, or other purposes. With an environmental goal to reduce emissions to very low levels, programs that become dependent on the revenue may come up short when and if carbon revenue begins to decline. To date, the revenue potential of a carbon tax has not been studied in detail. This study focuses on how much carbon tax revenue can be collected and whether there is a carbon “Laffer Curve” relationship, with a point where revenue begins to decline. We employ the MIT U.S. Regional Energy Policy (USREP) model, a dynamic computable general equilibrium model for the U.S. economy, for the numerical investigation of this question. We consider scenarios with different carbon prices and emissions reductions goals to explore how they may affect whether and at what tax rate revenues peak. We find that a sufficiently high tax rate would induce a revenue peak between now and 2050. For the scenarios we study, however, we find that carbon tax revenue is a dependable source of revenue to finance federal fiscal initiatives over a thirty-year period at the minimum. We also explore how the cost of low-carbon technology and existing energy policies interact with tax rates and revenues. Our results indicate that lower costs of abatement technology make emissions more responsive to the tax rate, and removing regulations on renewables and personal transportation results in more carbon tax revenues. Our results also show that either lowering technology costs or removing existing policies would reduce the welfare cost of a carbon policy with specific reduction goals, with a larger offsetting gain from eliminating distortions associated with existing policies.

The Future Water Risks Under Global Change in Southern and Eastern Asia: Implications of Mitigation

2017-07-01T00:00:00Z

The Future Water Risks Under Global Change in Southern and Eastern Asia: Implications of Mitigation Gao, X.; Schlosser, C.A.; Fant, C.; Strzepek, K. Understanding and predicting the future vulnerability of freshwater resources is a major challenge with important societal implications. Many studies have identified Asia as a hotspot of severe water stress in the coming decades, and also highlighted the large uncertainty associated with water resource assessment based on limited multi-model projections. Here we provide a more comprehensive risk-based assessment of water use and availability in response to future climate change, socioeconomic growth, and their combination in Southern and Eastern Asia. We employ a large ensemble of scenarios that capture the spectrum of regional climate response as well as a range of economic projections and climate policies in a consistent, integrated modeling framework. We show that economic growth increases water stress ubiquitously. The climate-only and combined climate-growth effects on water stress remain largely negative in China and Indus Basin, but largely positive in India, Indochina, and Ganges Basin. However, climate poses substantially large uncertainty in water stress changes than socioeconomic growth. By 2050, socioeconomic growth alone can lead to an additional 650 million people living under at least “heavy” water stress, with most of these located in India, Indus Basin, and China. The combined effects of socioeconomic growth and climate change reduce people under water stress to an additional 200 million, attributed mainly to the beneficial climate in India that moves its heavily-stressed condition into the slightly or moderately‑stressed conditions. These 200 million people primarily reside in Indus Basin and China under at least overly exploited water conditions— where total water requirements will consistently exceed surface water supply. Climate mitigation helps alleviating the risks of increasing water scarcity by midcentury, but to a limited extent. Therefore, adaptive measures need to be taken to meet these surface water shortfalls, or a combination of both approaches may be most effective.

Modeling the Income Dependence of Household Energy Consumption and its Implications for Climate Policy in China

2017-07-01T00:00:00Z

Modeling the Income Dependence of Household Energy Consumption and its Implications for Climate Policy in China Caron, J.; Karplus, V.J.; Schwarz, G.A. We estimate Engel Curves based on Chinese household microdata and show in general equilibrium simulations that they imply substantially lower energy demand and CO2 emissions, relative to projections based on standard assumptions of unitary income elasticity. Income-driven shifts in consumption reduce the average welfare cost of emissions pricing by more than half. Climate policy is also less regressive, as rising income leads to rapid convergence in the energy intensity of consumption baskets and more evenly distributed welfare loss across households. Our findings underscore the importance of correctly accounting for the relationship between income and energy demand in high-growth economies.

Global economic growth and agricultural land conversion under uncertain productivity improvements in agriculture

2017-06-01T00:00:00Z

Global economic growth and agricultural land conversion under uncertain productivity improvements in agriculture Lanz, B.; Dietz, S.; Swanson, T. We study how stochasticity in the evolution of agricultural productivity interacts with economic and population growth at the global level. We use a two-sector Schumpeterian model of growth, in which a manufacturing sector produces the traditional consumption good and an agricultural sector produces food to sustain contemporaneous population. Agriculture demands land as an input, itself treated as a scarce form of capital. In our model both population and sectoral technological progress are endogenously determined, and key technological parameters of the model are structurally estimated using 1960–2010 data on world GDP, population, cropland and technological progress. Introducing random shocks to the evolution of total factor productivity in agriculture, we show that uncertainty optimally requires more land to be converted into agricultural use as a hedge against production shortages, and that it significantly affects both optimal consumption and population trajectories.

Can Tariffs be Used to Enforce Paris Climate Commitments?

2017-06-01T00:00:00Z

Can Tariffs be Used to Enforce Paris Climate Commitments? Winchester, N. We evaluate the potential for using border carbon adjustments (BCAs) and welfare-maximizing tariffs to compel non-compliant countries to meet emissions reduction targets pledged under the Paris Climate Agreement. Our analysis employs a numerical economy-wide model with energy sector detail and, given recent actions by the new US administration, considers BCAs on US exports. We find that BCAs result in small reductions in US emissions and welfare. Consequently, the US is better off when it does not restrict emissions and faces BCAs on its exports than when it implements policies consistent with the Paris Agreement. However, targeted welfare-maximizing tariffs could inflict greater cost on the US than if it complied with its pledged emissions reductions. We conclude that BCAs are an ineffective enforcement mechanism but carefully chosen tariffs could be a mechanism to enforce the Paris Agreement.

A Review of and Perspectives on Global Change Modeling for Northern Eurasia

2017-05-01T00:00:00Z

A Review of and Perspectives on Global Change Modeling for Northern Eurasia Monier, E.; Kicklighter, D.; Sokolov, A.; Zhuang, Q.; Sokolik, I.; Lawford, R.; Kappas, M.; Paltsev, S.; Groisman, P. Northern Eurasia is made up of a complex and diverse set of physical, ecological, climatic and human systems, which provide important ecosystem services including the storage of substantial stocks of carbon in its terrestrial ecosystems. At the same time, the region has experienced dramatic climate change, natural disturbances and changes in land management practices over the past century. For these reasons, Northern Eurasia is both a critical region to understand and a complex system with substantial challenges for the modeling community. This review is designed to highlight the state of past and ongoing efforts of the research community to understand and model these environmental, socioeconomic, and climatic changes. We further aim to provide perspectives on the future direction of global change modeling to improve our understanding of the role of Northern Eurasia in the coupled human-Earth system. Major modeling efforts have shown that environmental and socioeconomic impacts in Northern Eurasia can have major implications for the biodiversity, ecosystems services, environmental sustainability, and carbon cycle of the region, and beyond. These impacts have the potential to feedback onto and alter the global Earth system. We find that past and ongoing studies have largely focused on specific components of Earth system dynamics and have not systematically examined their feedbacks to the global Earth system and to society. We identify the crucial role of Earth system models in advancing our understanding of feedbacks within the region and with the global system. We further argue for the need for Integrated Assessment Models (IAMs), a suite of models that couple human activity models to Earth system models, which are key to address many emerging issues that require a representation of the coupled human-Earth system.

The Future of Coal in China

2017-04-01T00:00:00Z

The Future of Coal in China Zhang, X.; Winchester, N.; Zhang, X. As the world’s largest consumer of total primary energy and energy from coal, and the largest emitter of carbon dioxide (CO2), China is now taking an active role in controlling CO2 emissions. Given current coal use in China, and the urgent need to cut emissions, ‘clean coal’ technologies are regarded as a promising solution for China to meet its carbon reduction targets while still obtaining a considerable share of energy from coal. Using an economy-wide model, this paper evaluates the impact of two existing advanced coal technologies—coal upgrading and ultra-supercritical (USC) coal power generation—on economic, energy and emissions outcomes when a carbon price is used to meet China’s CO2 intensity target out to 2035. Additional deployment of USC coal power generation lowers the carbon price required to meet the CO2 intensity target by more than 40% in the near term and by 25% in the longer term. It also increases total coal power generation and coal use. Increasing the share of coal that is upgraded leads to only a small decrease in the carbon price. As China’s CO2 intensity is set exogenously, additional deployment of the two technologies has a small impact on total CO2 emissions.

Climate Stabilization at 2°C and Net Zero Carbon Emissions

2017-03-01T00:00:00Z

Climate Stabilization at 2°C and Net Zero Carbon Emissions Sokolov, A.; Paltsev, S.; Chen, H.; Haigh, M.; Prinn, R.; Monier, E. The goal to stabilize global average surface temperature at lower than 2°C above pre-industrial level has been extensively discussed in climate negotiations. A number of publications state that achieving this goal will require net anthropogenic carbon emissions (defined as anthropogenic emissions minus anthropogenic sinks such as carbon capture and sequestration and reforestation) to be reduced to zero between years 2050 and 2100. At the same time, it is also shown in the literature that decreases of non-CO2 emissions can significantly affect the allowable carbon budget. In this study, we explore possible emission pathways under which surface warming will not exceed 2°C, by means of emission-driven climate simulations with an Earth System Model of Intermediate Complexity linked to an Economic Projection and Policy Analysis Model. We carried out a number of simulations from 1861 to 2500 for different values of parameters defining the strength of the climate system response to radiative forcing and the strength of the natural carbon sources and sinks under different anthropogenic emission projections. Although net anthropogenic emissions need to be reduced to zero eventually to achieve climate stabilization, the results of our simulations suggest that, by including significant reductions in non-CO2 emissions, net carbon emissions do not have to be zero by 2050 or even 2100 to meet the 2°C target because of offsets due to the natural carbon sinks in the oceans and terrestrial ecosystems. We show that net anthropogenic carbon emissions falling from today’s 9.5 GtC/year to 2.5–7 GtC/year by 2050 and then to 1–2.8 GtC/year by 2100 are consistent with a 2°C target for a range of climate sensitivities (2.0–4.5°C) similar to the IPCC likely range. Changes in the surface temperature beyond 2100 depend on the emission profiles after 2100. For post-2100 carbon emissions decreasing at a rate of about 1.5% per year along with continued decreases in non-CO2 emissions, our projections indicate that natural ecosystems will be able to absorb enough carbon to prevent surface temperature from rising further. A major reason for our results is that the land and ocean uptake rates are a function of the total atmospheric CO2 concentration and, due to the very long lifetime of CO2, this does not decrease anywhere near as fast as the imposed CO2 emissions. The required mixes of energy technologies and the overall costs to achieve the 2°C target are highly dependent on the assumptions about the future costs of low-carbon and zero-carbon emitting technologies. In all our projections, the global energy system requires substantial transformations in a relatively short time.

Transparency in the Paris Agreement

2017-02-01T00:00:00Z

Transparency in the Paris Agreement Jacoby, H.D.; Chen, Y.-H.H.; Flannery, B.P. Establishing a credible and effective transparency system will be both crucial and challenging for the climate regime based on the pledge and review process established in the Paris Agreement. The Agreement provides for review of achievements under national pledges (Nationally Determined Contributions, or NDCs), but much of this information will become available only well after key steps in the launch of this latest attempt to control human influence on the climate. Still, in these early years, information and understanding of individual and collective performance, and of relative national burdens under the NDCs, will play an important role in the success or failure of the Agreement. However, because of the phasing of various steps in the 5-year cycles under the Agreement and the unavoidable delays of two or more years to produce and review government reports, the Climate Convention and other intergovernmental institutions are ill-suited to carry out timely analyses of progress. Consequently, in advance of formal procedures, academic and other non-governmental groups are going to provide analyses based on available data and their own methodologies. We explore this transparency challenge, using the MIT Economic Projection and Policy Analysis (EPPA) model, to construct sample analyses, and consider ways that efforts outside official channels can make an effective contribution to the success of the Agreement.

Economic Projection with Non-homothetic Preferences: The Performance and Application of a CDE Demand System

2016-12-01T00:00:00Z

Economic Projection with Non-homothetic Preferences: The Performance and Application of a CDE Demand System Chen, Y.-H.H. In computable general equilibrium modeling, whether the simulation results are consistent to a set of valid own-price and income demand elasticities that are observed empirically remains a key challenge in many modeling exercises. To address this issue, the Constant Difference of Elasticities (CDE) demand system has been adopted by some models since the 1990s. However, perhaps due to complexities of the system, the applications of CDE systems in other models are less common. Furthermore, how well the system can represent the given elasticities is rarely discussed or examined in existing literature. The study aims at bridging these gaps by revisiting calibration details of the system, exploring conditions where the calibrated elasticities of the system can better match a set of valid target elasticities, and presenting strategies to incorporate the system into GTAP8inGAMS—a global computable general equilibrium model written in GAMS and MPSGE modeling languages. It finds that the calibrated elasticities can be matched to the target ones more precisely if the corresponding sectorial expenditure shares are lower, target own-price demand elasticities are lower, and target income demand elasticities are higher. It also verifies that for the GTAP8inGAMS with a CDE system, the model responses can successfully replicate the calibrated elasticities under various price and income shocks.

A Drought Indicator based on Ecosystem Responses to Water Availability: The Normalized Ecosystem Drought Index

2016-12-01T00:00:00Z

A Drought Indicator based on Ecosystem Responses to Water Availability: The Normalized Ecosystem Drought Index Chang, K.-Y.; Paw U, K.T.; Xu, L. Drought is one of the most destructive natural disasters causing serious damages to human society, and studies have projected more severe and widespread droughts in the coming decades associated with the warming climate. Although several drought indices have been developed for drought monitoring, most of them were based on large scale environmental conditions rather than ecosystem transitional patterns to drought. Here, we propose using the ecosystem function oriented Normalized Ecosystem Drought Index (NEDI) to quantify drought severity, loosely related to Sprengel’s and Liebig’s Law of the Minimum for plant nutrition. Extensive eddy covariance measurements from 60 AmeriFlux sites across 8 IGBP vegetation types were used to validate the use of NEDI. The results show that NEDI can reasonably capture ecosystem transitional responses to limited water availability, suggesting that drought conditions detected by NEDI are ecosystem function oriented. The wildly used Palmer Drought Severity Index (PDSI), on the other hand, does not have a clear relationship with ecosystem responses to drought conditions because ecosystem adaptation ability is not considered in PDSI calculation.

Is Current Irrigation Sustainable in the United States? An Integrated Assessment of Climate Change Impact on Water Resources and Irrigated Crop Yields

2016-11-01T00:00:00Z

Is Current Irrigation Sustainable in the United States? An Integrated Assessment of Climate Change Impact on Water Resources and Irrigated Crop Yields Blanc, É.; Caron, J.; Fant, C.; Monier, E. While the impact of climate change on crop yields has been extensively studied, the quantification of water shortages on irrigated crop yields has been regarded as more challenging due to the complexity of the water resources management system. To investigate this issue, we integrate a crop yield reduction module and a water resources model into the MIT Integrated Global System Modeling (IGSM) framework, an integrated assessment model that links a model of the global economy to an Earth system model. While accounting for uncertainty in climate change, we assess the effects of climate and socio-economic changes on the competition for water resources between industrial, energy, domestic and irrigation; the implications for water availability for irrigation; and the subsequent impacts on crop yields in the US by 2050. We find that climate and socio-economic changes will increase water shortages and strongly reduce irrigated crop yields in specific regions (mostly in the Southwest), or for specific crops (i.e. cotton and forage). While the most affected regions are usually not major crop growers, the heterogeneous response of crop yield to global change and water stress suggests that some level of adaptation can be expected, such as the relocation of cropland area to regions where irrigation is more sustainable. Finally, GHG mitigation has the potential to alleviate the effect of water stress on irrigated crop yields—enough to offset the reduced CO2 fertilization effect compared to an unconstrained GHG emission scenario.

The Impact of Oil Prices on Bioenergy, Emissions and Land Use

2016-10-01T00:00:00Z

The Impact of Oil Prices on Bioenergy, Emissions and Land Use Winchester, N.; Ledvina, K. We evaluate how alternative future oil prices will influence the penetration of biofuels, energy production, greenhouse gas (GHG) emissions, land use and other outcomes. Our analysis employs a global economy wide model and simulates alternative oil prices out to 2050 with and without a price on GHG emissions. In one case considered, based on estimates of available resources, technological progress and energy demand, the reference oil price rises to $124 by 2050. Other cases separately consider constant reference oil prices of $50, $75 and $100, which are targeted by adjusting the quantity of oil resources. In our simulations, higher oil prices lead to more biofuel production, more land being used for bioenergy crops, and fewer GHG emissions. Reducing oil resources to simulate higher oil prices has a strong income effect, so decreased food demand under higher oil prices results in an increase in land allocated to natural forests. We also find that introducing a carbon price reduces the differences in oil use and GHG emissions across oil price cases.

Scaling Compliance with Coverage? Firm-level Performance in China’s Industrial Energy Conservation Program

2016-10-01T00:00:00Z

Scaling Compliance with Coverage? Firm-level Performance in China’s Industrial Energy Conservation Program Karplus, V.J.; Shen, X.; Zhang, D. Industrial energy conservation programs in China form a cornerstone of China’s energy and environmental management efforts, engaging thousands of major energy-using enterprises, and targeting hundreds of million tons of annual coal-equivalent energy savings during the Eleventh and Twelfth Five-Year Plans (2006 to 2015). An important question in China and other developing countries is to understand how compliance systems develop and perform, especially in settings where regulators have limited prior experience and resources to support evaluation and enforcement. We use detailed, newly-released compliance reports, combined with industrial census data on participating firms, to identify the drivers of compliance at the firm level. We find evidence consistent with manipulation of reported compliance data during the Eleventh Five-Year Plan (2006–2010), but not during the expanded program under the Twelfth Five-Year Plan (2011–2015). We show that the non-compliance rate increased with the expansion of the program, and publicly-reported reasons for non-compliance vary widely. We find that firms that are large, and new program entrants, as well as firms in cities with low growth exhibit higher non-compliance rates after program expansion. Our findings demonstrate that although expanding coverage increases potential energy savings, regulators must grapple with increased heterogeneity in firms’ internal energy-saving opportunities and capabilities as well as in the degree of external accountability to regulators. Introducing a market for energy saving or CO2 emissions may help to solve the problem of uneven abatement costs, but differences in the strength of accountability relationships could undermine performance.

21st Century Changes in U.S. Heavy Precipitation Frequency Based on Resolved Atmospheric Patterns

2016-10-01T00:00:00Z

21st Century Changes in U.S. Heavy Precipitation Frequency Based on Resolved Atmospheric Patterns Gao, X.; Schlosser, C.A.; O'Gorman, P.; Monier, E.; Entekhabi, D. Gridded precipitation-gauge observations and global atmospheric reanalysis are combined to develop an analogue method for detecting the occurrence of heavy precipitation events based on the prevailing large-scale atmospheric conditions. Combinations of different atmospheric variables for circulation features (geopotential height and wind vector) and moisture plumes (surface specific humidity, column precipitable water, and precipitable water up to 500hPa) are examined to construct the analogue schemes for the winter (DJF) of the Pacific Coast California (PCCA) and the summer (JJA) of the Midwestern United States (MWST). The detection diagnostics of various analogue schemes are calibrated with 27-yr (1979–2005) and then validated with 9-yr (2006–2014) NASA Modern-Era Retrospective Analysis for Research and Applications (MERRA). All of the analogue schemes are found to significantly improve upon MERRA precipitation in characterizing the number and interannual variations of observed heavy precipitation events in the MWST which is one of weakest regions for MERRA summer precipitation. When evaluated with the late 20th century simulations from an ensemble of climate models participating in the Coupled Model Intercomparison Project Phase 5 (CMIP5), all analogue schemes produce model medians of heavy precipitation frequency that are more consistent with observations and have smaller inter-model discrepancies when compared with the model-based precipitation. Further, the performances of analogue schemes with vector winds are comparable to those of geopotential height, and no analogue scheme with one of three water vapor content variables is clearly superior to another. Under two radiative forcing scenarios (Representative Concentration Pathways 4.5 and 8.5), the CMIP5-based analogue schemes produce a trend in the occurrence of heavy events through the 21st century consistent with the model-based precipitation, but with smaller inter-model disparity. The strongest reduction in the disparity of the results is seen for the RCP8.5 scenario. The median trends in DJF heavy precipitation frequency for PCCA are positive, but for JJA heavy event frequency over the MWST region, the median trends are slightly negative. Overall, the presented analyses highlight the potential of the analogue as a powerful diagnostic tool for model deficiencies and its complementarity to an evaluation that considers modeled precipitation alone to assess heavy precipitation frequency. The consistency found here between projections from analogues and model precipitation increases confidence in projected heavy precipitation frequency changes in a warming climate.

Combining Price and Quantity Controls under Partitioned Environmental Regulation

2016-07-01T00:00:00Z

Combining Price and Quantity Controls under Partitioned Environmental Regulation Abrell, J.; Rausch, S. This paper analyzes hybrid emissions trading systems (ETS) under partitioned environmental regulation when firms’ abatement costs and future emissions are uncertain. We show that hybrid policies that introduce bounds on the price or the quantity of abatement provide a way to hedge against differences in marginal abatement costs across partitions. Price bounds are more efficient than abatement bounds as they also use information on firms’ abatement technologies while abatement bounds can only address emissions uncertainty. Using a numerical stochastic optimization model with equilibrium constraints for the European carbon market, we find that introducing hybrid policies in EU ETS reduces expected excess abatement costs of achieving targeted emissions reductions under EU climate policy by up to 89 percent. We also find that under partitioned regulation there is a high likelihood for hybrid policies to yield sizeable ex-post cost reductions.

The Impact of Water Scarcity on Food, Bioenergy and Deforestation

2016-07-01T00:00:00Z

The Impact of Water Scarcity on Food, Bioenergy and Deforestation Winchester, N.; Ledvina, K.; Strzepek, K.; Reilly, J.M. We evaluate the impact of explicitly representing irrigated land and water scarcity in an economy-wide model on food prices, bioenergy production and deforestation both with and without a global carbon policy. The analysis develops supply functions of irrigable land from a water resource model resolved at 282 river basins and applies them within a global economy-wide model of energy and food production, land-use change and greenhouse gas emissions. The irrigable land supply curves are built on basin-level estimates of water availability, and the costs of improving irrigation efficiency and increasing water storage, and include other water requirements within each basin. The analysis reveals two key findings. First, explicitly representing irrigated land at has a small impact on food, bioenergy and deforestation outcomes. This is because this modification allows more flexibility in the expansion of crop land (i.e. irrigated and rainfed land can expand in different proportions) relative to when a single type of crop land is represented, which counters the effect of rising marginal costs for the expansion of irrigated land. Second, due to endogenous irrigation and storage responses, changes in water availability have small impacts on food prices, bioenergy production, land-use change and the overall economy, even with large scale (~150 exajoules) bioenergy production.

The Impact of Coordinated Policies on Air Pollution Emissions from Road Transportation in China

2016-07-01T00:00:00Z

The Impact of Coordinated Policies on Air Pollution Emissions from Road Transportation in China Kishimoto, P.N.; Karplus, V.J.; Zhong, M.; Saikawa, E.; Zhang, X.; Zhang, X. Improving air quality across mainland China is an urgent policy challenge. While much of the problem is linked to China’s broader reliance on coal and other fossil fuels across the energy system, road transportation is an important and growing source of air pollution. Here we use an energy-economic model, embedded in the broader Regional Emissions Air Quality Climate and Health (REACH) modeling framework, to analyze the impacts of implementing vehicle emissions together with a broader economy-wide climate policy on total air pollution and its spatial distribution. We find that full and immediate implementation of existing vehicle emissions standards at China 3/III level or tighter will significantly reduce the contribution of transportation to degraded air quality by 2030. We further show that transportation emissions standards function as an important complement to an economy-wide price on CO2, which delivers significant co-benefits for air pollution reduction that are concentrated primarily in non-transportation sectors. Going forward, vehicle emissions standards and an economy-wide carbon price form a highly effective coordinated policy package that supports China’s air quality and climate change mitigation goals.

Modeling Regional Carbon Dioxide Flux over California using the WRF‑ACASA Coupled Model

2016-07-01T00:00:00Z

Modeling Regional Carbon Dioxide Flux over California using the WRF‑ACASA Coupled Model Xu, L.; Pyles, R.D.; Paw U, K.T.; Chen, S.-H.; Monier, E.; Falk, M. Many processes and interactions in the atmosphere and the biosphere influence the rate of carbon dioxide exchange between these two systems. However, it is difficult to estimate the carbon dioxide flux over regions with diverse ecosystems and complex terrains, such as California. Traditional carbon dioxide measurements are sparse and limited to specific ecosystems. Therefore, accurately estimating carbon dioxide flux on a regional scale remains a major challenge. In this study, we couple the Weather Research and Forecasting Model (WRF) with the Advanced Canopy-Atmosphere-Soil Algorithm (ACASA), a high complexity land surface model. Although WRF is a state-of-the-art regional atmospheric model with high spatial and temporal resolutions, the land surface schemes available in WRF lack the capability to simulate carbon dioxide. ACASA is a complex multilayer land surface model with interactive canopy physiology and full surface hydrological processes. It allows microenvironmental variables such as air and surface temperatures, wind speed, humidity, and carbon dioxide concentration to vary vertically. Carbon dioxide, sensible heat, water vapor, and momentum fluxes between the atmosphere and land surface are estimated in the ACASA model through turbulence equations with a third order closure scheme. It therefore permits counter-gradient transports that low-order turbulence closure models are unable to simulate. A new CO2 tracer module is introduced into the model framework to allow the atmospheric carbon dioxide concentration to vary according to terrestrial responses. In addition to the carbon dioxide simulation, the coupled WRF-ACASA model is also used to investigate the interactions of neighboring ecosystems in their response to atmospheric carbon dioxide concentration. The model simulations with and without the CO2 tracer for WRF-ACASA are compared with surface observations from the AmeriFlux network.

Electricity Investments under Technology Cost Uncertainty and Stochastic Technological Learning

2016-05-10T00:00:00Z

Electricity Investments under Technology Cost Uncertainty and Stochastic Technological Learning Morris, Jennifer; Webster, Mort; Reilly, John Given that electricity generation investments are expected to operate for 40 or more years, the decisions we make today can have long-term impacts on the electricity system and the ability and cost of meeting long-term environmental goals. This research investigates socially optimal near-term electricity investment decisions under uncertainty in future technology costs and policy by formulating a computable general equilibrium (CGE) model of the U.S. as a two-stage stochastic dynamic program. The unique feature of the study is a stochastic formulation of technological learning. Most studies that include technological learning utilize deterministic learning curves in which a given amount of investment, production or capacity leads to a given cost reduction. In a stochastic framework, investment in a technology in the current period depends on uncertain learning that will result and lower future costs of the technology. Results under stochastic technological learning suggest that additional near-term investment relative to what is optimal under no learning can be justified at technological learning rates as low as 10–15%, and at the 20–25% rates commonly found in literature for advanced non-carbon technologies, significant additional near-term investment can be justified. We also find it can be socially optimal to invest more in non-carbon technology when the rate of learning is uncertain compared to the case where the learning rate is certain. Increasing marginal costs produce an asymmetric loss function that under uncertainty leads to more near-term non-carbon investment in attempt to avoid the situation of high non-carbon costs and an external economic environment that creates high demand for non-carbon technology.

Statistical Emulators of Maize, Rice, Soybean and Wheat Yields from Global Gridded Crop Models

2016-05-09T00:00:00Z

Statistical Emulators of Maize, Rice, Soybean and Wheat Yields from Global Gridded Crop Models Blanc, Elodie This study provides statistical emulators of crop yields based on global gridded crop model simulations from the Inter-Sectoral Impact Model Intercomparison Project Fast Track project. The ensemble of simulations is used to build a panel of annual crop yields from five crop models and corresponding monthly summer weather variables for over a century at the grid cell level globally. This dataset is then used to estimate, for each crop and gridded crop model, the statistical relationship between yields, temperature, precipitation and carbon dioxide. This study considers a new functional form to better capture the non-linear response of yields to weather, especially for extreme temperature and precipitation events. In- and out-of-sample validations show that the statistical emulators are able to closely replicate crop yields projected by crop models and perform well out-of-sample. This study therefore provides a reliable and accessible alternative to global gridded crop yield models. By emulating crop yields for several models using parsimonious equations, the tools provide a computationally efficient method to account for uncertainty in climate change impact assessments.

Are Land-use Emissions Scalable with Increasing Corn Ethanol Mandates in the United States?

2016-04-01T00:00:00Z

Are Land-use Emissions Scalable with Increasing Corn Ethanol Mandates in the United States? Ejaz, Qudsia J.; Paltsev, Sergey; Kicklighter, David W.; Winchester, Niven W. In response to the Renewable Fuel Standard, the U.S. transportation sector now consumes a substantial amount (13.3 billion gallons in 2010) of ethanol. A key motivation for these mandates is to expand the consumption of biofuels in road transportation to both reduce foreign oil dependency and to reduce greenhouse gas (GHG) emissions from the consumption of fossil fuels in transportation. In this paper, we present the impacts of several biofuels expansion scenarios for the U.S. in which scaled increases in the U.S. corn ethanol mandates are modeled to explore the scalability of GHG impacts. The impacts show both expected and surprising results. As expected, the area of land used to grow biofuel crops increases with the size of the policy in the U.S., and some land-use changes occur abroad due to trade in agricultural commodities. Because the land-use changes happen largely in the U.S., there is an increase in U.S. land-use emissions when natural lands are converted to agricultural use in the policy scenarios. Further, the emissions impacts in the U.S. and the rest of the world in these scenarios, including land-use emissions, scale in direct proportion to the size of the U.S. corn ethanol mandates. On the other hand, the land-use emissions that occur in the rest of the world are disproportionately larger per hectare of change due to conversions of more carbon-rich forests to cultivate crops and feed livestock.

The Future of Natural Gas in China: Effects of Pricing Reform and Climate Policy

2016-03-01T00:00:00Z

The Future of Natural Gas in China: Effects of Pricing Reform and Climate Policy Zhang, Danwei; Paltsev, Sergey China is currently attempting to reduce greenhouse gas emissions and increase natural gas consumption as a part of broader national strategies to reduce the air pollution impacts of the nation’s energy system. To assess the scenarios of natural gas development up to 2050, we employ a global energy-economic model—the MIT Economic Projection and Policy Analysis (EPPA) model. The results show that a cap-and-trade policy will enable China to achieve its climate mitigation goals, but will also reduce natural gas consumption. An integrated policy that uses a part of the carbon revenue obtained from the cap-and-trade system to subsidize natural gas use promotes natural gas consumption, resulting in a further reduction in coal use relative to the cap-and-trade policy case. The integrated policy has a very moderate welfare cost; however, it reduces air pollution and allows China to achieve both the climate objective and the natural gas promotion objective.

Uncertainty in Future Agro-Climate Projections in the United States and Benefits of Greenhouse Gas Mitigation

2016-03-01T00:00:00Z

Uncertainty in Future Agro-Climate Projections in the United States and Benefits of Greenhouse Gas Mitigation Monier, E.; Xu, L.; Snyder, R. Scientific challenges exist on how to extract information from the wide range of projected impacts simulated by crop models driven by climate ensembles. A stronger focus is required to understand and identify the mechanisms and drivers of projected changes in crop yield. In this study, we investigate the robustness of future projections of five metrics relevant to agriculture stakeholders (accumulated frost days, dry days, growing season length, plant heat stress and start of field operations). We use a large ensemble of climate simulations by the MIT IGSM-CAM integrated assessment model that accounts for the uncertainty associated with different emissions scenarios, climate sensitivity, and natural variability. By end of century, the US is projected to experience fewer frosts, a longer growing season, more heat stress and an earlier start of field operations—although the magnitude and even the sign of these changes vary greatly by regions. Projected changes in dry days are shown not to be robust. We highlight the important role of natural variability, in particular for changes in dry days (a precipitation-related index) and heat stress (a threshold index). The wide range of our projections compares well the CMIP5 multi-model ensemble, especially for temperature-related indices. This suggests that using a single climate model that accounts for key sources of uncertainty can provide an efficient and complementary framework to the more common approach of multi-model ensembles. We also show that greenhouse gas mitigation has the potential to significantly reduce adverse effects (heat stress, risks of pest and disease) of climate change on agriculture, while also curtailing potentially beneficial impacts (earlier planting, possibility for multiple cropping). A major benefit of climate mitigation is potentially preventing changes in several indices to emerge from the noise of natural variability, even by 2100. This has major implications considering that any significant climate change impacts on crop yield would result in nation-wide changes in the agriculture sector. Finally, we argue that the analysis of agro-climate indices should more often complement crop model projections, as they can provide valuable information to better understand the drivers of changes in crop yield and production and thus better inform adaptation decisions.

Costs of Climate Mitigation Policies

2016-03-01T00:00:00Z

Costs of Climate Mitigation Policies Chen, Y.-H.H.; Babiker, M.; Paltsev, S.; Reilly, J. The wide range of cost estimates for stabilizing climate is puzzling to policy makers as well as researchers. Assumptions about technology costs have been studied extensively as one reason for these differences. Here, we focus on how policy timing and the modeling of economy-wide interactions affect costs. We examine these issues by restructuring a general equilibrium model of the global economy, removing elements of the model one by one. We find that delaying the start of a global policy by 20 years triples the needed starting carbon price and increases the macroeconomic cost by nearly 30%. We further find that including realistic details of the economy (e.g. sectoral and electricity technology detail; tax and trade distortions; capital vintaging) more than double net present discounted costs over the century. Inter-model comparisons of stabilization costs find a similar range, but it is not possible to isolate the structural causes behind cost differences. Broader comparisons of stabilization costs face the additional issue that studies of different vintages assume different policy starting dates, often dates that are no longer realistic given the pace of climate change negotiations. This study can aid in interpretation of estimates and give policymakers and researchers an idea of how to adjust costs upwards as the start of policy is delayed. It also illustrates that models that greatly simplify the realities of modern economies likely underestimate costs.

Scenarios of Global Change: Integrated Assessment of Climate Impacts

2016-02-01T00:00:00Z

Scenarios of Global Change: Integrated Assessment of Climate Impacts Paltsev, S.; Sokolov, A.; Chen, H.; Gao, X.; Schlosser, A.; Monier, E.; Fant, C.; Scott, J.; Ejaz, Q.; Couzo, E.; Prinn, R.; Haigh, M. Using the MIT Integrated Global System Modeling (IGSM) framework, we assess the climate impacts of emission scenarios exhibiting global mean surface temperatures ranging between 2.4°C and 4.3°C above pre-industrial by 2100. We compare the outcomes from these forward-looking scenarios against the common goal described by the target-driven scenario of 2°C. Without further policy measures, the agreement at COP-21 in Paris is projected to result in a 3.5°C increase in global temperature in 2100 relative to pre-industrial levels. Scenarios developed by Shell International (called Mountains and Oceans) exhibit a substantial movement towards temperature stabilization, as they result in increases of only 2.4–2.7°C by 2100. Valuable components of these scenarios include a substantial shift to renewable energy and deployment of carbon capture and storage (CCS). These scenarios are successful in mitigating a large portion of water stress impacts and air pollution damages. They also significantly mitigate increases in ocean acidity. These projections show the significant value of policies that do not quite reach 2°C stabilization, but fall substantially close to that target by the end of the century. The challenge of meeting the Paris Agreement’s aspiration to limit warming to 1.5°C is monumental, yet may be desirable if societies see the 2°C impacts, described here, as running too much risk.

Modeling Uncertainty in Climate Change: A Multi-Model Comparison

2015-12-01T00:00:00Z

Modeling Uncertainty in Climate Change: A Multi-Model Comparison Gillingham, K.; Nordhaus, W.; Anthoff, D.; Blanford, G.; Bosetti, V.; Christensen, P.; McJeon, H.; Reilly, J.; Sztorc, P. The economics of climate change involves a vast array of uncertainties, complicating both the analysis and development of climate policy. This study presents the results of the first comprehensive study of uncertainty in climate change using multiple integrated assessment models. The study looks at model and parametric uncertainties for population, total factor productivity, and climate sensitivity. It estimates the pdfs of key output variables, including CO2 concentrations, temperature, damages, and the social cost of carbon (SCC). One key finding is that parametric uncertainty is more important than uncertainty in model structure. Our resulting pdfs also provide insights on tail events.

The Impact of Climate Policy on Carbon Capture and Storage Deployment in China

2015-12-01T00:00:00Z

The Impact of Climate Policy on Carbon Capture and Storage Deployment in China Zhang, X.; Qi, T.; Zhang, X. Carbon capture and storage (CCS) from coal combustion is widely viewed as an important approach for China’s carbon dioxide (CO2) emission mitigation, but the pace of its development is still fairly slow. In addition to the technological and economic uncertainties of CCS, lack of strong policy incentive is another main reason for the wide gap between early expectations and the actual progress towards its demonstration and commercialization. China’s mitigation scenario and targets are crucial to long-term development of CCS. In this research, impacts of CCS on energy and CO2 emissions are evaluated under two mitigation scenarios reflecting different policy effort levels for China using the China-in-Global Energy Model (C-GEM). Results indicate that with CCS applications in the power sector China can achieve an added emissions reduction of 0.3 to 0.6 Gigatons CO2 (GtCO2) in 2050 at the same level of carbon taxes respectively in the two mitigation scenarios. Under the more ambitious mitigation scenario, approximately 56% of China’s fossil fuel fired power plants will have CCS installed, and CO2 emission amounting to 1.4 GtCO2 will be captured in 2050. A carbon price not lower than $35/tCO2 appears to be necessary for the large-scale application of CCS in the power sector, indicating the vital role of policy in the deployment of CCS in China’s power sector.

The Influence of Gas-to-Liquids and Natural Gas Production Technology Penetration on the Crude Oil-Natural Gas Price Relationship

2015-12-01T00:00:00Z

The Influence of Gas-to-Liquids and Natural Gas Production Technology Penetration on the Crude Oil-Natural Gas Price Relationship Ramberg, D.J.; Chen, Y.-H.H.; Paltsev, S.; Parsons, J.E. The paper examines conditions under which gas-to-liquids (GTL) technology penetration shifts the crude oil-natural gas price ratio. Technologies that enable direct substitution across fuels, as GTL does, may constrain the price ratio within certain bounds. We analyze the forecasted evolution of the crude oil-natural gas price ratio over the next several decades under alternative assumptions about the availability and cost of GTL and its natural gas feedstock. We do this using a computable general equilibrium model of the global economy with a focus on the refinery sector in the U.S. Absent GTL, a base case forecast of global economic growth over the next few decades produces dramatic increases in the oil-natural gas price ratio. This is because there is a more limited supply of low-cost crude oil resources than natural gas resources. The availability of GTL at conventional forecasts of cost and efficiency does not materially change the picture because it is too expensive to enhance direct competition between the two as fuels in the transportation sector. GTL only modulates the increasing oil-gas price ratio if both (i) natural gas is much cheaper to produce, and (ii) GTL is less costly and more efficient than conventional forecasts.

Impact of Canopy Representations on Regional Modeling of Evapotranspiration using the WRF-ACASA Coupled Model

2015-12-01T00:00:00Z

Impact of Canopy Representations on Regional Modeling of Evapotranspiration using the WRF-ACASA Coupled Model Xu, L.; Pyles, R.D.; Paw U, K.T.; Snyder, R.; Monier, E.; Falk, M.; S.-H., Chen In this study, we couple the Weather Research and Forecasting Model (WRF) with the Advanced Canopy-Atmosphere-Soil Algorithm (ACASA), a high complexity land surface model, to investigate the impact of canopy representation on regional evapotranspiration. The WRF-ACASA model uses a multilayer structure to represent the canopy, consequently allowing microenvironmental variables such as leaf area index (LAI), air and canopy temperature, wind speed and humidity to vary both horizontally and vertically. The improvement in canopy representation and canopy-atmosphere interaction allow for more realistic simulation of evapotranspiration on both regional and local scales. Accurate estimates of evapotranspiration (both potential and actual) are especially important for regions with limited water availability and high water demand, such as California. Water availability has been and will continue to be the most important issue facing California for years and perhaps decades to come. Terrestrial evapotranspiration is influenced by many processes and interactions in the atmosphere and the bio-sphere such as water, carbon, and momentum exchanges. The need to improve representation within of surface-atmosphere interactions remains an urgent priority within the modeling community.

Launching a New Climate Regime

2015-11-01T00:00:00Z

Launching a New Climate Regime Jacoby, H.D.; Chen, Y.-H.H. At the 2015 UN Framework Convention on Climate Change (UNFCCC) meeting in Paris, participants in a new international climate agreement will volunteer Nationally Determined Contributions to emissions reductions. To put the planet on a path to declared temperature goals, the growth of global greenhouse gas emissions must cease, and begin to decline, by 2035 to 2040; however, the expected contributions do not yield results consistent with this timeline. Three achievements in Paris and follow-on activities are then crucial components of the new climate regime: a robust system of review with widely accepted measures of national effort; an established, durable plan of future pledge cycles; and increased financial support for the mitigation efforts of less developed countries. The MIT Economic Projection and Policy Analysis (EPPA) model is applied to assess emissions outcomes of expected pledges and national performances in meeting them, and to elaborate the components of a successful launch.

US Major Crops’ Uncertain Climate Change Risks and Greenhouse Gas Mitigation Benefits

2015-10-01T00:00:00Z

US Major Crops’ Uncertain Climate Change Risks and Greenhouse Gas Mitigation Benefits Sue Wing, I.; Monier, E.; Stern, A.; Mundra, A. We estimate the costs of climate change to US agriculture, and associated potential benefits of abating greenhouse gas emissions. Five major crops yield responses to climatic variation are modeled empirically, and the results combined with climate projections for a no-policy, high-warming future, as well as moderate and stringent mitigation scenarios. Unabated warming reduces yields of wheat and soybeans by 2050, and cotton by 2100, but moderate warming increases yields of all crops except wheat. Yield changes are monetized using the results of economic simulations within an integrated climate-economy modeling framework. The economic effects of uncontrolled warming on major crops are slightly positive—annual benefits < $4B. These are amplified by emission reductions, but subject to diminishing returns—by 2100 reaching $17B under moderate mitigation, but only $7B with stringent mitigation. Costs and benefits are sensitive to irreducible uncertainty about the fertilization effects of elevated atmospheric carbon dioxide, without which unabated warming incurs net costs of up to $18B, generating benefits to moderate (stringent) mitigation as large as $26B ($20B).

Capturing Natural Resource Dynamics in Top-Down Energy‑Economic Equilibrium Models

2015-10-01T00:00:00Z

Capturing Natural Resource Dynamics in Top-Down Energy‑Economic Equilibrium Models Zhang, D.; Karplus, V.; Rausch, S. Top-down energy-economic modeling approaches often use deliberately simple techniques to represent heterogeneous resource inputs to production. We show that for some policies, such as feed-in tariffs (FIT) for renewable electricity, detailed representation of renewable resource grades is required to describe the technology more precisely and identify cost-effective policy designs. We extend a hybrid approach for modeling heterogeneity in the quality of natural resource inputs required for renewable energy production in a stylized computable general equilibrium (CGE) framework. Importantly, this approach resolves nearflat or near-vertical sections of the resource supply curve that translate into key features of the marginal cost of wind resource supply, allowing for more realistic policy simulation. In a second step, we represent the shape of a resource supply curve based on more detailed data. We show that for the case of onshore wind development in China, a differentiated FIT design that can only be modeled with the hybrid approach requires less than half of the subsidy budget needed for a uniform FIT design and proves to be more cost-effective.

Natural Gas Pricing Reform in China: Getting Closer to a Market System?

2015-07-01T00:00:00Z

Natural Gas Pricing Reform in China: Getting Closer to a Market System? Paltsev, S.; Zhang, D. Recent policy in China targets an increase in the contribution of natural gas to the nation’s energy supply. Historically, China’s natural gas prices have been highly regulated with a goal to protect consumers. The old pricing regime failed to provide enough incentives for natural gas suppliers, which often resulted in natural gas shortages. A new gas pricing reform was tested in Guangdong and Guangxi provinces in 2011 and was introduced nationwide in 2013. The reform is aimed at creating a more market based pricing mechanism. We show that substantial progress toward better predictability and transparency of prices has been made. China’s prices are now more connected with international fuel oil and liquid petroleum gas prices. The government’s approach for temporary two tier pricing when some volumes are still traded at old prices reduced potential opposition during the new regime implementation. Some limitations created by the natural gas pricing remain: it created biased incentives for producers and favors large natural gas suppliers. The pricing reform at its current stage falls short of establishing a complete market mechanism driven by an interaction of supply and demand of natural gas in China.

The Impact of Climate Policy on Carbon Capture and Storage Deployment in China

2015-12-28T00:00:00Z

The Impact of Climate Policy on Carbon Capture and Storage Deployment in China Zhang, Xiaohan; Qi, Tianyu; Zhang, Xiliang Carbon capture and storage (CCS) from coal combustion is widely viewed as an important approach for China’s carbon dioxide (CO2) emission mitigation, but the pace of its development is still fairly slow. In addition to the technological and economic uncertainties of CCS, lack of strong policy incentive is another main reason for the wide gap between early expectations and the actual progress towards its demonstration and commercialization. China’s mitigation scenario and targets are crucial to long-term development of CCS. In this research, impacts of CCS on energy and CO2 emissions are evaluated under two mitigation scenarios reflecting different policy effort levels for China using the China-in-Global Energy Model (C-GEM). Results indicate that with CCS applications in the power sector China can achieve an added emissions reduction of 0.3 to 0.6 Gigatons CO2 (GtCO2) in 2050 at the same level of carbon taxes respectively in the two mitigation scenarios. Under the more ambitious mitigation scenario, approximately 56% of China’s fossil fuel fired power plants will have CCS installed, and CO2 emission amounting to 1.4 GtCO2 will be captured in 2050. A carbon price not lower than $35/tCO2 appears to be necessary for the large-scale application of CCS in the power sector, indicating the vital role of policy in the deployment of CCS in China’s power sector.

Global population growth, technology, and Malthusian constraints: A quantitative growth theoretic perspective

2015-10-01T00:00:00Z

Global population growth, technology, and Malthusian constraints: A quantitative growth theoretic perspective Lanz, B.; Dietz, S.; Swanson, T. We structurally estimate a two-sector Schumpeterian growth model with endogenous population and finite land reserves to study the long run evolution of global population, technological progress and the demand for food. The estimated model closely replicates trajectories for world population, GDP, sectoral productivity growth and crop land area from 1960 to 2010. Projections from 2010 onwards show a slowdown of technological progress, and because it is a key determinant of fertility costs, significant population growth. By 2100 global population reaches 12 billion and agricultural production doubles, but the land constraint does not bind because of capital investment and technological progress.

Impacts of CO2 Mandates for New Cars in the European Union

2015-05-01T00:00:00Z

Impacts of CO2 Mandates for New Cars in the European Union Paltsev, S.; Chen, Y.-H.H.; Karplus, V.; Kishimoto, P.; Reilly, J. CO2 emissions mandates for new light-duty passenger vehicles have recently been adopted in the European Union (EU), which require steady reductions to 95 g CO2/km in 2021. Using a computable general equilibrium (CGE) model, we analyze the impact of the mandates on oil demand, CO2 emissions, and economic welfare, and compare the results to an emission trading scenario that achieves identical emissions reductions. We find that the mandates lower oil expenditures by about €6 billion, but at a net added cost of €12 billion in 2020. Emissions from transport are about 50MtCO2 lower with the vehicle emission standards, but with the economy-wide emission trading, lower emissions in transport allow an equal increase in emissions elsewhere in the economy. We estimate that tightening CO2 standards further after 2020 would cost the EU economy an additional €24–63 billion in 2025 compared with achieving the same reductions with an economy-wide emission trading system.

Water Body Temperature Model for Assessing Climate Change Impacts on Thermal Cooling

2015-05-01T00:00:00Z

Water Body Temperature Model for Assessing Climate Change Impacts on Thermal Cooling Strzepek, K.; Fant, C.; Gebretsadik, Y.; Lickley, M.; Boehlert, B.; Chapra, S.; Adams, E.; Strzepek, A.; Schlosser, C.A. We develop and test a physically based semi-Lagrangian water body temperature model to apply climatological data and thermal pollution from river-based power plants to historical river flow data in order to better understand climate change impacts on surface water temperature and thermal power plant withdrawal allowances. The model is built for rapid assessment and use in Integrated Assessment Models. We first test the standalone model on a 190km river reach, the Delaware River, where we have detailed flow and temperature data. An R2 of 0.88 is obtained on hourly data for this initial test. Next, we integrate the standalone temperature model into a series of models—rainfall-runoff model, water demand model, water resource management model, and power plant uptake and release model—for the contiguous USA (CONUS), with about 19,000 segments total. With this system in place, we then validate the standalone water temperature model within the system for 16 river stations throughout the CONUS, where we have measured daily temperature data. The model performs reasonably well with a median R2 of 0.88. A variety of climate and emissions scenarios are then applied to the model to test regions of higher vulnerability to river temperature environmental violations, making use of output from two GCMs and six emissions scenarios focusing on projections out to 2050. We find that the two GCMs project significantly different impacts to water temperature, driven largely by the resulting changes in streamflow from the two models. We also find significantly different impacts on the withdrawal allowed by thermal power plants due to environmental regulations. Potential impacts on generation are between +3% and -4% by 2050 for the unconstrained emissions case and +3.5% to -2% for the stringent GHG mitigation policy (where 1% is equivalent to 32 TWh, or about 3 billion USD/year using 2005 electricity prices). We also find that once-through cooling plants are most vulnerable to climate change impacts, with summer impacts ranging from -0.8% to -6% for the unconstrained emissions case and +2.1% to -3.7% for the stringent GHG emissions case.

Capturing Natural Resource Dynamics in Top-Down Energy‑Economic Equilibrium Models

2015-10-20T00:00:00Z

Capturing Natural Resource Dynamics in Top-Down Energy‑Economic Equilibrium Models Zhang, Da; Karplus, V.; Rausch, S. Top-down energy-economic modeling approaches often use deliberately simple techniques to represent heterogeneous resource inputs to production. We show that for some policies, such as feed-in tariffs (FIT) for renewable electricity, detailed representation of renewable resource grades is required to describe the technology more precisely and identify cost-effective policy designs. We extend a hybrid approach for modeling heterogeneity in the quality of natural resource inputs required for renewable energy production in a stylized computable general equilibrium (CGE) framework. Importantly, this approach resolves nearflat or near-vertical sections of the resource supply curve that translate into key features of the marginal cost of wind resource supply, allowing for more realistic policy simulation. In a second step, we represent the shape of a resource supply curve based on more detailed data. We show that for the case of onshore wind development in China, a differentiated FIT design that can only be modeled with the hybrid approach requires less than half of the subsidy budget needed for a uniform FIT design and proves to be more cost-effective.

Natural Gas Pricing Reform in China: Getting Closer to a Market System?

2015-08-31T00:00:00Z

Emulating maize yields from global gridded crop models using statistical estimates

2015-03-01T00:00:00Z

Emulating maize yields from global gridded crop models using statistical estimates Blanc, E.; Sultan, B. This study estimates statistical models emulating maize yield responses to changes in temperature and precipitation simulated by global gridded crop models. We use the unique and newly-released Inter-Sectoral Impact Model Intercomparison Project Fast Track ensemble of global gridded crop model simulations to build a panel of annual maize yields simulations from five crop models and corresponding monthly weather variables for over a century. This dataset is then used to estimate statistical relationships between yields and weather variables for each crop model. The statistical models are able to closely replicate both in- and out-of-sample maize yields projected by the crop models. This study therefore provides simple tools to predict gridded changes in maize yields due to climate change at the global level. By emulating crop yields for several models, the tools will be useful for climate change impact assessments and facilitate evaluation of crop model uncertainty.

The MIT EPPA6 Model: Economic Growth, Energy Use, and Food Consumption

2015-03-01T00:00:00Z

The MIT EPPA6 Model: Economic Growth, Energy Use, and Food Consumption Chen, Y.-H.H.; Paltsev, S.; Reilly, J.M.; Morris, J.F.; Babiker, M.H. The MIT Economic Projection and Policy Analysis (EPPA) model has been broadly applied on energy and climate policy analyses. In this paper, we provide an updated version of the model based on the most recent global economic database with the base year data of 2007. Also new in this version of the model are non-homothetic preferences, a revised capital vintaging structure, separate accounting of residences, and an improved model structure that smooths its functioning and makes future extensions easier. We compare reference (“business-as-usual”) and policy results for the latest model to the previous version. We also present how projections for the final consumption of food and agricultural products are improved with non-homothetic preferences, and how various assumptions for reference GDP growth, elasticity of substitution between energy and non-energy input, and autonomous energy efficiency improvement may change CO2 emissions and prices.

Renewables Intermittency: Operational Limits and Implications for Long-Term Energy System Models

2015-03-01T00:00:00Z

Renewables Intermittency: Operational Limits and Implications for Long-Term Energy System Models Delarue, E.; Morris, J. In several regions of the world, the share of intermittent renewables (such as wind and solar PV) in electricity generation is rapidly increasing. The current share of these renewable energy sources (RES) can still more or less be handled by existing systems and flexibility, benefiting from remaining excess capacity of dispatchable (backup) generation and links to other grids that can balance the intermittency. However, often higher levels of intermittent RES are envisaged for the future, posing significant challenges on system operation and planning. In assessing possible energy futures, long-term energy system models are typically used. The representation of RES in such models needs careful attention, as intermittent RES come with a number of specific characteristics, making them different from conventional dispatchable generation. This paper focuses on technical implications related to systems trying to achieve high shares of renewable electricity. The relevance of demand and RES generation profiles are demonstrated. After some threshold, a sharp decreasing relationship between installed RES capacity and marginal contribution in terms of generation is identified; therefore, even with perfect backup, a technical limit exists on achievable RES shares. The impact of RES on net demand peak reduction is also addressed. In the absence of system flexibility, substantial backup is required to ensure reliable electricity provision. The role of different flexibility instruments is explored and is found to be significant. Reflections are provided on options to include these aspects in long-term energy system models.

Specifying Parameters in Computable General Equilibrium Models using Optimal Fingerprint Detection Methods

2015-02-01T00:00:00Z

Specifying Parameters in Computable General Equilibrium Models using Optimal Fingerprint Detection Methods Koesler, S. The specification of parameters is a crucial task in the development of economic models. The objective of this paper is to improve the standard parameter specification of computable general equilibrium (CGE) models. On that account, we illustrate how Optimal Fingerprint Detection Methods (OFDM) can be used to identify appropriate values for various parameters. These methods originate from climate science and combine a simple model validation exercise with a structured sensitivity analysis. The new approach has three main benefits: 1) It uses a structured optimisation procedure and does not revert to ad-hoc model improvements. 2) It accounts for uncertainty in parameter estimates by using information on the distribution of parameter estimates from the literature. 3) It can be applied for the specification of a range of parameters required in CGE models; for example, for the definition of elasticities or productivity growth rates.

The Impact of Advanced Biofuels on Aviation Emissions and Operations in the U.S.

2015-02-01T00:00:00Z

The Impact of Advanced Biofuels on Aviation Emissions and Operations in the U.S. Winchester, N.; Malina, R.; Staples, M.D.; Barrett, S.R.H. We analyze the economic and emissions impacts on U.S. commercial aviation of the Federal Aviation Administration’s renewable jet fuel goal when met using advanced fermentation (AF) fuel from perennial grasses. These fuels have recently been certified for use in aircraft and could potentially provide greater environmental benefits than aviation biofuels approved previously. Due to uncertainties in the commercialization of AF technologies, we consider a range of assumptions concerning capital costs, energy conversion efficiencies and product slates. In 2030, estimates of the implicit subsidy required to induce consumption of AF jet fuel range from $0.45 to $20.85 per gallon. These correspond to a reference jet fuel price of $3.23 per gallon and AF jet fuel costs ranging from 4.01 to $24.41 per gallon. In all cases, as renewable jet fuel represents around 1.4% of total fuel consumed by commercial aviation, the goal has a small impact on aviation operations and emissions relative to a case without the renewable jet fuel target, and emissions continue to grow relative to those in 2005. Costs per metric ton of carbon dioxide equivalent abated by using biofuels range from $42 to $652.

The Contribution of Biomass to Emissions Mitigation under a Global Climate Policy

2015-01-01T00:00:00Z

The Contribution of Biomass to Emissions Mitigation under a Global Climate Policy Winchester, N.; Reilly, J.M. What will large-scale global bioenergy production look like? We investigate this question by developing a detailed representation of bioenergy in a global economy-wide model. We develop a scenario with a global carbon dioxide price, applied to all anthropogenic emissions except those from land-use change, that rises from $15 per metric ton in 2015 to $59 in 2050. This creates market conditions favorable to biomass energy, resulting in global non traditional bioenergy production of ~150 exajoules (EJ) in 2050. By comparison, in 2010 global energy production was primarily from coal (139 EJ), oil (175 EJ) and gas (108 EJ). With this policy, 2050 emissions are 16% less in our Base Policy case than our Reference case, although extending the scope of the carbon price to include emissions from land-use change would reduce 2050 emissions by 57% relative to the same baseline. Our results from various policy scenarios show that lignocellulosic (LC) ethanol may become the major form of bioenergy, if its production costs fall by amounts predicted in a recent survey and ethanol blending constraints disappear by 2030; however, if its costs remain higher than expected or the ethanol blend wall continues to bind, bioelectricity and bioheat may prevail. Higher LC ethanol costs may also result in expanded production of first-generation biofuels (ethanol from sugarcane and corn) so that they remain in the fuel mix through 2050. Deforestation occurs if emissions from land-use change are not priced, although the availability of biomass residues and improvements in crop yields and conversion efficiencies mitigate pressure on land markets. As regions are linked via international agricultural markets, irrespective of the location of bioenergy production, natural forest decreases are largest in regions with the lowest political constraints to deforestation. The combination of carbon price and bioenergy production increases food prices by 2.6%–4.7%, with bioenergy accounting for 1.3%–2.6%.

Modeling regional transportation demand in China and the impacts of a national carbon constraint

2015-01-30T00:00:00Z

Modeling regional transportation demand in China and the impacts of a national carbon constraint Kishimoto, Paul Climate and energy policy in China will have important and uneven impacts on the country’s regionally heterogeneous transport system. In order to simulate these impacts, transport sector detail is added to a multi-sector, static, global computable general equilibrium (CGE) model which resolves China’s provinces as distinct regions. This framework is used to perform an analysis of national-level greenhouse gas (GHG) policies. Freight, commercial passenger and household (private vehicle) transport are separately represented, with the former two categories further disaggregated into road and non-road modes. The preparation of model inputs is described, including assembly of a provincial transport data set from publicly-available statistics. Two policies are analyzed: the first represents China’s target of a 17% reduction in GHG emissions intensity of GDP during the Twelfth Five Year Plan (12FYP), and the second China’s Copenhagen target of a 40–45% reduction in the same metric during the period 2005–2020. We find significant heterogeneity in regional transport impacts. We find that both freight and passenger transportation in some of the poorest provinces are most adversely affected, as their energy-intensive resource and industrial sectors offer many of the least-cost abatement opportunities, and the transformation of their energy systems strongly affects transport demand. At the national level, we find that road freight is the transport sector affected most by policy, likely due to its high energy intensity and limited low-cost opportunities for improving efficiency. The type and degree of regional disparity in impacts is relevant to central and provincial government decisions which set and allocate climate, energy and transport policy targets. We describe how this research establishes a basis for regional CGE analysis of the economic, energy and environmental impacts of transport-focused policies including vehicle ownership restrictions, taxation of driving activity or fuels, and the supply of public transit.

Advanced Technologies in Energy-Economy Models for Climate Change Assessment

2014-12-01T00:00:00Z

Advanced Technologies in Energy-Economy Models for Climate Change Assessment Morris, J.F.; Reilly, J.M.; Chen, Y.-H.H. Considerations regarding the roles of advanced technologies are crucial in energy-economic modeling, as these technologies, while usually not yet commercially viable, could substitute for fossil energy when relevant policies are in place. To improve the representation of the penetration of advanced technologies, we present a formulation that is parameterized based on observations, while capturing elements of rent and real cost increases if high demand suddenly appears due to large policy shock. The formulation is applied to a global economy-wide model to study the roles of low carbon alternatives in the power sector. While other modeling approaches often adopt specific constraints on expansion, our approach is based on the assumption and observation that these constraints are not absolute—the rate at which advanced technologies will expand is endogenous to economic incentives. The policy simulations are designed to illustrate the response under sudden increased demand for the advanced technologies, and are not intended to represent necessarily realistic price paths for greenhouse gas emissions.

International Trade in Natural Gas: Golden Age of LNG?

2014-11-01T00:00:00Z

International Trade in Natural Gas: Golden Age of LNG? Du, Y.; Paltsev, S. The introduction of liquefied natural gas (LNG) as an option for international trade has created a market for natural gas where global prices may eventually be differentiated by the transportation costs between world regions. LNG’s trade share in 2013 was only about 30 percent of the total global trade in natural gas, but use of LNG is on the rise with numerous projects in planning or construction stages. Considering LNG projects that are under construction, planned, or proposed, we provide an analysis of LNG prospects for the next decade. LNG has substantial unexploited potential in terms of reducing capital requirements (especially for liquefaction projects), expanding new technology frontiers (e.g. floating LNG), serving new markets, and establishing new pricing schemes that better reflect the fundamentals of supply and demand. Trade volumes are projected to increase from about 240 Mt LNG in 2013 to about 340–360 Mt LNG in 2021. Despite potential challenges from weaker demand in Asia, longer-term projections show that LNG trade is bound to show substantial growth, partially due to geopolitical tensions that might increase LNG flows to Europe. However, these perspectives largely depend on demand choices, the availability and evolution of alternative fuels (e.g. renewable energies), and—most importantly—political decisions framing economic behavior.

A Framework for Analysis of the Uncertainty of Socioeconomic Growth and Climate Change on the Risk of Water Stress: a Case Study in Asia

2014-11-01T00:00:00Z

A Framework for Analysis of the Uncertainty of Socioeconomic Growth and Climate Change on the Risk of Water Stress: a Case Study in Asia Fant, C.; Schlosser, C.A.; Gao, X.; Strzepek, K.; Reilly, J. The sustainability of future water resources is of paramount importance and is affected by many factors, including population, wealth and climate. Inherent in how these factors change in the future is the uncertainty of their prediction. In this study, we integrate a large ensemble of scenarios—internally consistent across economics, emissions, climate, and population—to develop a risk portfolio of water stress over a large portion of Asia that includes China, India, and Mainland Southeast Asia. We isolate the effects of socioeconomic growth from the effects of climate change in order to identify the primary drivers of stress on water resources. We find that water needs related to socioeconomic changes, which are currently small, are likely to increase considerably in the future, often overshadowing the effect of climate change on levels of water stress. As a result, there is a high risk of severe water stress in densely populated watersheds by 2050, compared to recent history. If socio-economic growth is unconstrained by global actions to limit greenhouse gas concentrations, water-stressed populations may increase from about 800 million to 1.7 billion in this region.

Interprovincial Migration and the Stringency of Energy Policy in China

2014-12-02T00:00:00Z

Interprovincial Migration and the Stringency of Energy Policy in China Luo, Xiaohu; Zhang, Da; Caron, Justin; Zhang, Xiliang; Karplus, Valerie Interprovincial migration flows involve substantial relocation of people and productive activity, with implications for regional energy use and greenhouse gas emissions. In China, these flows are not explicitly considered when setting energy and environmental targets for provinces, and their potential impact on the effectiveness of policy alternatives is ignored. We analyze how migration affects outcomes under energy intensity targets and energy caps. While both policies are part of the nation’s Twelfth Five Year Plan (2011–2015) and imposed at the provincial level, only the intensity targets are binding at present. We estimate a migration model, integrate it into a general equilibrium model that resolves each province in China, and simulate the effect of migration on energy use and economic activity. We find that although both types of policies are affected by uncertain migration flows, energy intensity targets (energy use indexed to economic output) are more robust than absolute caps. They are also more cost-effective, placing less burden on the relatively clean in-migration provinces. Our findings also underscore the value of moving from provincial targets to an integrated national emissions trading system, given that the choice of abatement strategies will adjust endogenously to labor relocation.

Characterization of the Solar Power Resource in Europe and Assessing Benefits of Co-Location with Wind Power Installations

2014-10-01T00:00:00Z

Characterization of the Solar Power Resource in Europe and Assessing Benefits of Co-Location with Wind Power Installations Bozonnat, C.; Schlosser, C.A. The extent, availability and reliability of solar power generation are assessed over Europe, and—following a previously developed methodology—special attention is given to the intermittency of solar power. Combined with estimates of wind power resource over Europe from a companion assessment, we assess the benefits of co-location of solar and wind power installations, particularly with respect to aggregate power generation and local mitigation of intermittency. Consistent with previous studies, our results show that the majority of solar potential is found in southern Europe, which also displays the strongest availability. We also found that higher latitude locations, around central Europe, benefit from medium to high solar power during the warm season. If a region’s availability of solar power is sufficient—as determined by a minimum technological threshold for photovoltaic extraction— it possesses the potential to reduce intermittency by aggregation and interconnection. We find these conditions occurring to a moderate extent over mainland central Europe. Finally, the result of co location of wind and solar power is increased power availability over the whole continent, especially in central Europe where neither resource is strong. In terms of local intermittency mitigation, the regions that benefit most are the Mediterranean and Baltic countries.

The CO2 Content of Consumption Across US Regions: A Multi-Regional Input-Output (MRIO) Approach

2014-08-01T00:00:00Z

The CO2 Content of Consumption Across US Regions: A Multi-Regional Input-Output (MRIO) Approach Caron, J.; Metcalf, G.; Reilly, J. We improve on existing estimates of the carbon dioxide (CO2) content of consumption across regions of the United States. Using a multi-regional input-output (MRIO) framework, we estimate the direct and indirect CO2 emissions attributable to domestically and internationally imported goods. We include estimates of bilateral trade between US states as well as between individual states and international countries and regions. This report presents two major findings. First, attributing emissions to states on a consumption versus a production basis leads to very different state-level emissions responsibilities; for example, when attributed on a consumption basis, California's per capita emissions are over 25 percent higher than when attributed on a production basis. Second, when attributing emissions on a consumption basis, heterogeneity of emissions across trading partners significantly affects emissions intensity. These findings have important implications for evaluating the potential distributional impacts of national climate policies, as well as for understanding differing incentives to implement state- or regional-level policies.

Coupling the High Complexity Land Surface Model ACASA to the Mesoscale Model WRF

2014-08-01T00:00:00Z

Coupling the High Complexity Land Surface Model ACASA to the Mesoscale Model WRF Xu, L.; Pyles, R.D.; Paw U, K.T.; Chen, S.-H.; Monier, E. In this study, the Weather Research and Forecasting Model (WRF) is coupled with the Advanced Canopy-Atmosphere-Soil Algorithm (ACASA), a high complexity land surface model. Although WRF is a state-of-the-art regional atmospheric model with high spatial and temporal resolutions, the land surface schemes available in WRF are simple and lack the capability to simulate carbon dioxide (for example, the popular NOAH LSM). ACASA is a complex multilayer land surface model with interactive canopy physiology and full surface hydrological processes. It allows microenvironmental variables such as air and surface temperatures, wind speed, humidity, and carbon dioxide concentration to vary vertically. // Simulations of surface conditions such as air temperature, dew point temperature, and relative humidity from WRF-ACASA and WRF-NOAH are compared with surface observation from over 700 meteorological stations in California. Results show that the increase in complexity in the WRF-ACASA model not only maintains model accuracy, it also properly accounts for the dominant biological and physical processes describing ecosystem-atmosphere interactions that are scientifically valuable. The different complexities of physical and physiological processes in the WRF-ACASA and WRF-NOAH models also highlight the impacts of various land surface and model components on atmospheric and surface conditions.

Expectations for a New Climate Agreement

2014-08-01T00:00:00Z

Expectations for a New Climate Agreement Jacoby, H.D.; Chen, Y.-H.H. With the objective of stimulating timely and open discussion of the current attempt to formulate a new climate agreement—to be reached at the 21st meeting of the Conference of Parties (COP-21) in Paris during November of 2015—analysis is conducted of the expected developments in the lead-up negotiations. Based on the assumption that the architecture of the agreement will likely involve voluntary pledges and ex-post review (akin to the Copenhagen Accord), the domestic policies and measures expected to underlie national negotiating positions are described. Applying a global economic model, the effect of these Nationally Determined Contributions (NDCs) on global greenhouse gas emissions is assessed. The analysis shows that an agreement likely achievable at COP-21 will succeed in a useful bending the curve of global emissions. The likely agreement will not, however, produce global emissions within the window of paths to 2050 that are consistent with frequently proposed climate goals, raising questions about follow-up steps in the development of a climate regime.

Markets versus Regulation: The Efficiency and Distributional Impacts of U.S. Climate Policy Proposals

2014-05-01T00:00:00Z

Markets versus Regulation: The Efficiency and Distributional Impacts of U.S. Climate Policy Proposals Rausch, S.; Karplus, V.J. Regulatory measures have proven the favored approach to climate change mitigation in the U.S., while market-based policies have gained little traction. Using a model that resolves the U.S. economy by region, income category, and sector-specific technology deployment opportunities, this paper studies the magnitude and distribution of economic impacts under regulatory versus market-based approaches. We quantify heterogeneity in the national response to regulatory policies, including a fuel economy standard and a clean or renewable electricity standard, and compare these to a cap–and–trade system targeting carbon dioxide or all greenhouse gases. We find that the regulatory policies substantially exceed the cost of a cap–and–trade system at the national level. We further show that the regulatory policies yield large cost disparities across regions and income groups, which are exaggerated by the difficulty of implementing revenue recycling provisions under regulatory policy designs.

Electricity Generation and Emissions Reduction Decisions under Policy Uncertainty: A General Equilibrium Analysis

2014-04-01T00:00:00Z

Electricity Generation and Emissions Reduction Decisions under Policy Uncertainty: A General Equilibrium Analysis Morris, J.; Webster, M.; Reilly, J. The electric power sector, which accounts for approximately 40% of U.S. carbon dioxide emissions, will be a critical component of any policy the U.S. government pursues to confront climate change. In the context of uncertainty in future policy limiting emissions, society faces the following question: What should the electricity mix we build in the next decade look like? We can continue to focus on conventional generation or invest in low-carbon technologies. There is no obvious answer without explicitly considering the risks created by uncertainty. // This research investigates socially optimal near-term electricity investment decisions under uncertainty in future policy. It employs a novel framework that models decision-making under uncertainty with learning in an economy-wide setting that can measure social welfare impacts. Specifically, a computable general equilibrium (CGE) model of the U.S. is formulated as a two-stage stochastic dynamic program focused on decisions in the electric power sector. // In modeling decision-making under uncertainty, an optimal electricity investment hedging strategy is identified. Given the experimental design, the optimal hedging strategy reduces the expected policy costs by over 50% compared to a strategy derived using the expected value for the uncertain parameter; and by 12-400% compared to strategies developed under a perfect foresight or myopic framework. This research also shows that uncertainty has a cost, beyond the cost of meeting a policy. Results show that uncertainty about the future policy increases the expected cost of policy by over 45%. If political consensus can be reached and the climate science uncertainties resolved, setting clear, long-term policies can minimize expected policy costs. // Ultimately, this work demonstrates that near-term investments in low-carbon technologies should be greater than what would be justified to meet near-term goals alone. Near-term low-carbon investments can lower the expected cost of future policy by developing a less carbon-intensive electricity mix, spreading the burden of emissions reductions over time, and helping to overcome technology expansion rate constraints—all of which provide future flexibility in meeting a policy. The additional near-term cost of low-carbon investments is justified by the future flexibility that such investments create. The value of this flexibility is only explicitly considered in the context of decision-making under uncertainty.

A Self-Consistent Method to Assess Air Quality Co-Benefits from US Climate Policies

2014-04-01T00:00:00Z

A Self-Consistent Method to Assess Air Quality Co-Benefits from US Climate Policies Saari, R.; Selin, N.E.; Rausch, S.; Thompson, T.M. Air quality co-benefits can potentially reduce the costs of greenhouse gas mitigation. However, while many studies of the cost of greenhouse gas mitigation model the full macroeconomic welfare impacts, most studies of air quality co-benefits do not. We employ a US computable general equilibrium economic model previously linked to an air quality modeling system, and enhance it to represent the economy-wide welfare impacts of fine particulate matter. We present a first application of this method to explore the efficiency and the distributional implications of a clean energy standard (CES) and a cap–and–trade (CAT) program that both reduce CO2 emission by 10% in 2030 relative to 2006. We find that co-benefits from fine particulate matter reduction completely offset policy costs by 110% (40% to 190%), transforming the net welfare impact of the CAT into a gain of $1 (-$5 to $7) billion 2005 US$. For the CES, the corresponding co-benefit (median $8; $3 to $14)/tCO2 is a smaller fraction (median 5%; 2% to 9%) of its higher policy cost. The eastern US garners 78% and 71% of co-benefits for the CES and CAT, respectively. By representing the effects of pollution-related morbidities and mortalities as an impact to labor and the demand for health services, we find that the welfare impact per unit of reduced pollution varies by region. These interregional differences can enhance the preference of some regions, like Texas, for a CAT over a CES, or switch the calculation of which policy yields higher co-benefits, compared to an approach that uses one valuation for all regions. This framework could be applied to quantify consistent air quality impacts of other pricing instruments, subnational trading programs, or green tax swaps.

Characterization of the Wind Power Resource in Europe and its Intermittency

2014-03-01T00:00:00Z

Characterization of the Wind Power Resource in Europe and its Intermittency Cosseron, A.; Schlosser, C.A.; Gunturu, U.B. Wind power is assessed over Europe, with special attention given to the quantification of intermittency. Using the methodology developed in Gunturu and Schlosser (2011), the MERRA boundary flux data was used to compute wind power density profiles over Europe. Besides of the analysis of capacity factor, other metrics are presented to further quantify the availability and reliability of this resource and the extent to which wind-power intermittency is coincident across Europe. The analyses find that, consistent with previous studies, the majority of European wind power resources are located offshore. The largest wind power resources at onshore locations are found to be over Iceland, the United Kingdom, and along the northern coastlines of continental Europe. Other isolated pockets of higher wind power are found over Spain and along the Mediterranean coast of France. Overall, the availability of onshore wind power is low and is highly intermittent, while offshore locations show a high degree of persistence. However, for the strongest onshore locations of wind power—primarily over northern coastlines as well as the United Kingdom and Iceland—the evidence indicates that intermittency can be reduced by aggregation and interconnection of wind-power installations.

The Potential Wind Power Resource in Australia: A New Perspective

2014-02-01T00:00:00Z

The Potential Wind Power Resource in Australia: A New Perspective Hallgren, Willow; Gunturu, Udaya Bhaskar; Schlosser, C. Adam Australia is considered to have very good wind resources, and the utilization of this renewable energy resource is increasing. Wind power installed capacity increased by 35% from 2006 to 2011 and is predicted to account for over 12% of Australia’s electricity generation in 2030. This study uses a recently published methodology to address the limitations of previous wind resource analyses, and frames the nature of Australia’s wind resources from the perspective of economic viability, using robust metrics of the abundance, variability and intermittency of wind power density, and analyzes whether these differ with higher wind turbine hub heights. We also assess the extent to which wind intermittency can potentially be mitigated by the aggregation of geographically dispersed wind farms. Our results suggest that over much of Australia, areas that have high wind intermittency coincide with large expanses in which the aggregation of turbine output does not mitigate variability. These areas are also geographically remote, some are disconnected from the east coast’s electricity grid and large population centers, and often are not connected or located near enough to high capacity electricity infrastructure, all of which would decrease the potential economic viability of wind farms in these locations. However, on the eastern seaboard, even though the wind resource is weaker, it is less variable, much closer to large population centers, and there exists more potential to mitigate its intermittency through aggregation.

Carbon emissions in China: How far can new efforts bend the curve?

2014-10-01T00:00:00Z

Carbon emissions in China: How far can new efforts bend the curve? Zhang, Xiliang; Karplus, Valerie J.; Qi, Tianyu; Zhang, Da; He, Jiankun While China is on track to meet its global climate commitments through 2020, China’s post-2020 CO2 emissions trajectory is highly uncertain, with projections varying widely across studies. Over the past year, the Chinese government has announced new policy directives to deepen economic reform, protect the environment, and limit fossil energy use in China. To evaluate how new policy directives could affect energy and climate change outcomes, we simulate two levels of policy effort—a Continued Effort scenario that extends current policies beyond 2020 and an Accelerated Effort scenario that reflects newly announced policies—on the evolution of China’s energy and economic system over the next several decades. Importantly, we find that both levels of policy effort would bend down the CO2 emissions trajectory before 2050 without undermining economic development, although coal use and CO2 emissions peak about 10 years earlier in the Accelerated Effort scenario.

The China-in-Global Energy Model

2014-05-01T00:00:00Z

The China-in-Global Energy Model Qi, T.; Winchester, N.; Zhang, D.; Zhang, X.; Karplus, V.J. The China-in-Global Energy Model (C-GEM) is a global Computable General Equilibrium (CGE) model that captures the interaction of production, consumption and trade among multiple global regions and sectors – including five energy-intensive sectors – to analyze global energy demand, CO2 emissions, and economic activity. The C-GEM model supplies a research platform to analyze China’s climate policy and its global implications, and is one of the major output and analysis tools developed by the China Energy and Climate Project (CECP) – a cooperative project between the Tsinghua University Institute of Energy, Environment, and Economy and the Massachusetts Institute of Technology (MIT) Joint Program on the Science and Policy of Global Change. This report serves as technical documentation to describe the C-GEM model. We provide detailed information on the model structure, underlying database, key parameters and its calibration, and important assumptions about the model. We also provide model results for the reference scenario and a sensitivity analysis for two key parameters: autonomous energy efficiency improvements (AEEI) and the elasticity of substitution between energy and value added.

An Integrated Assessment of China’s Wind Energy Potential

2014-04-01T00:00:00Z

An Integrated Assessment of China’s Wind Energy Potential Zhang, D.; Davidson, M.; Gunturu, B.; Zhang, X.; Karplus, V.J. Computable general equilibrium (CGE) models seeking to evaluate the impacts of electricity policy face difficulties incorporating detail on the variable nature of renewable energy resources. To improve the accuracy of modeling renewable energy and climate policies, detailed scientific and engineering data are used to inform the parameterization of wind electricity in a new regional CGE model of China. Wind power density (WPD) in China is constructed using boundary layer flux data from the Modern Era Retrospective-analysis for Research and Applications (MERRA) dataset with a 0.5° latitude by 0.67° longitude spatial resolution. Wind resource data are used to generate production cost functions for wind at the provincial level for both onshore and offshore, incorporating technological parameters and geographical constraints. By using these updated wind production cost data to parameterize the wind electricity option in a CGE model, an illustrative policy analysis of the current feed-in tariff (FIT) for onshore wind electricity is performed. Assuming a generous penetration rate, no grid integration cost and no interprovincial interconnection, we find that the economic potential of wind exceeds China’s 2020 wind target by a large margin. Our analysis shows how wind electricity resource can be differentiated based on location and quality in a CGE model and then applied to analyze climate and energy policies.

Equity and Emissions Trading in China

2014-02-01T00:00:00Z

Equity and Emissions Trading in China Zhang, D.; Springmann, M.; Karplus, V.J. China has embarked on an ambitious pathway for establishing a national carbon market in the next five to ten years. In this study, we analyze the distributional aspects of a Chinese emissions-trading scheme from ethical, economic, and stated-preference perspectives. We focus on the role of emissions permit allocation and first show how specific equity principles can be incorporated into the design of potential allocation schemes. We then assess the economic and distributional impacts of those allocation schemes using a computable general equilibrium model with regional detail for the Chinese economy. Finally, we conduct a survey among Chinese climate-policy experts on the basis of the simulated model impacts. The survey participants indicate a relative preference for allocation schemes that put less emissions-reduction burden on the western provinces, a medium burden on the central provinces, and a high burden on the eastern provinces. Most participants show strong support for allocating emissions permits based on consumption-based emissions responsibilities.

The Mercury Game: Evaluating a Negotiation Simulation that Teaches Students about Science–Policy Interactions

2014-01-01T00:00:00Z

The Mercury Game: Evaluating a Negotiation Simulation that Teaches Students about Science–Policy Interactions Stokes, Leah C.; Selin, Noelle E. Environmental negotiations and policy decisions take place at the science–policy interface. While this is well known in academic literature, it is often difficult to convey how science and policy interact to students in environmental studies and sciences courses. We argue that negotiation simulations, as an experiential learning tool, are one effective way to teach students about how science and policy interact in decision-making. We developed a negotiation simulation, called the Mercury Game, based on the global mercury treaty negotiations. To evaluate the game, we conducted surveys before and after the game was played in university classrooms across North America. For science students, the simulation communicates how politics and economics affect environmental negotiations. For environmental studies and policy students, the mercury simulation demonstrates how scientific uncertainty can affect decision-making. Using the mercury game as an education tool allows students to learn about complex interactions between science and society and develop communication skills.

The Future of Global Water Stress: An Integrated Assessment

2014-01-01T00:00:00Z

The Future of Global Water Stress: An Integrated Assessment Schlosser, C. Adam; Strzepek, Kenneth M.; Gao, Xiang; Gueneau, Arthur; Fant, Charles; Paltsev, Sergey; Rasheed, Bilhuda; Smith-Greico, Tony; Blanc, Elodie; Jacoby, Henry D.; Reilly, John M. We assess the ability of global water systems, resolved at 282 large river basins or Assessment Sub Regions (ASRs), to the meet water requirements over the coming decades under integrated projections of socioeconomic growth and climate change. We employ a Water Resource System (WRS) component embedded within the MIT Integrated Global System Model (IGSM) framework in a suite of simulations that consider a range of climate policies and regional hydroclimatic changes through the middle of this century. We find that for many developing nations water-demand increases due to population growth and economic activity have a much stronger effect on water stress than climate change. By 2050, economic growth and population change alone can lead to an additional 1.8 billion people living in regions with at least moderate water stress. Of this additional 1.8 billion people, 80% are found in developing countries. Uncertain regional climate change can play a secondary role to either exacerbate or dampen the increase in water stress due to socioeconomic growth. The strongest climate impacts on relative changes in water stress are seen over many areas in Africa, but strong impacts also occur over Europe, Southeast Asia and North America. The combined effects of socioeconomic growth and uncertain climate change lead to a 1.0 to 1.3 billion increase of the world's 2050 projected population living in regions with overly exploited water conditions— where total potential water requirements will consistently exceed surface-water supply. Under the context of the WRS model framework, this would imply that adaptive measures would be taken to meet these surface-water shortfalls and would include: water-use efficiency, reduced and/or redirected consumption, recurrent periods of water emergencies or curtailments, groundwater depletion, additional inter-basin transfers, and overdraw from flow intended to maintain environmental requirements.

An Analogue Approach to Identify Extreme Precipitation Events: Evaluation and Application to CMIP5 Climate Models in the United States

2013-11-01T00:00:00Z

An Analogue Approach to Identify Extreme Precipitation Events: Evaluation and Application to CMIP5 Climate Models in the United States Gao, Xiang; Schlosser, C. Adam; Xie, Pingping; Monier, Erwan; Entekhabi, Dara Global warming is expected to alter the frequency, intensity, and risk of extreme precipitation events. However, global climate models in general do not correctly reproduce the frequency and intensity distribution of precipitation, especially at the regional scale. We present an analogue method to detect the occurrence of extreme precipitation events without relying on modeled precipitation. Our approach is based on the use of composites to identify the distinct large-scale atmospheric conditions associated with widespread outbreaks of extreme precipitation events across local scales. The development of composite maps, exemplified in the South-Central United States and the Western United States, is achieved through the joint analysis of 27-yr (1979–2005) CPC gridded station data and NASA's Modern Era Retrospective-analysis for Research and Applications (MERRA). Various circulation features and moisture plumes associated with extreme precipitation events are examined. This analogue method is evaluated against the MERRA reanalysis with a success rate of around 80% in detecting extreme events within one or two days. When applied to the climate model simulations of the 20th century from Coupled Model Intercomparison Project Phase 5 (CMIP5), we find the analogues from the CMIP5 models produces more consistent (and less uncertain) total number of extreme events compared against observations as opposed to using their corresponding simulated precipitation over the three regions examined. The analogues also perform better to characterize the interannual range of extreme days with the smaller RMSE across all the models for all the descriptive statistics (minimum, lower and higher quartile, median, and maximum). These results suggest the capability of CMIP5 models to simulate the realistic large-scale atmospheric conditions associated with widespread local-scale extreme events, with a credible frequency. Collectively speaking, the presented analyses clearly highlight the comparative and enhanced nature of these results to studies that consider only modeled precipitation output to assess extreme-event frequency.

Synergy between Pollution and Carbon Emissions Control: Comparing China and the U.S.

2013-10-01T00:00:00Z

Synergy between Pollution and Carbon Emissions Control: Comparing China and the U.S. Nam, Kyung-Min; Waugh, Caleb J.; Paltsev, Sergey; Reilly, John M.; Karplus, V.J. We estimate the potential synergy between pollution and climate control in the U.S. and China, summarizing the results as emissions cross-elasticities of control. We set a range of NOx and SO2 targets, and record the ancillary reduction in CO2 to calculate the percentage change in CO2 divided by the percentage change in NOx (SO2) denoted as ECO2,NOx (ECO2,SO2). Then we conduct the opposite experiment, setting targets for CO2 and recording the ancillary reduction in NOx and SO2 to compute ENOx,CO2 and ESO2,CO2. For ECO2,NOx and ECO2,SO2 we find low values (0.06‒0.23) in both countries with small (10%) reduction targets that rise to 0.40‒0.67 in the U.S. and 0.83‒1.03 in China when targets are more stringent (75% reduction). This pattern reflects the availability of pollution control to target individual pollutants for smaller reductions but the need for wholesale change toward non-fossil technologies when large reductions are required. We trace the especially high cross elasticities in China to its higher dependence on coal. These results are promising in that China may have more incentive to greatly reduce SO2 and NOx with readily apparent pollution benefits in China, that at the same time would significantly reduce CO2 emissions. The majority of existing studies have focused on the effect of CO2 abatement on other pollutants, typically finding strong cross effects. We find similar strong effects but with less dependence on the stringency of control, and stronger effects in the U.S. than in China.

Regulatory Control of Vehicle and Power Plant Emissions: How Effective and at What Cost?

2013-10-01T00:00:00Z

Regulatory Control of Vehicle and Power Plant Emissions: How Effective and at What Cost? Paltsev, S.; Karplus, V.; Chen, Y.-H.H.; Karkatsouli, I.; Reilly, J.M.; Jacoby, H.D. Passenger vehicles and power plants are major sources of greenhouse gas emissions. While economic analyses generally indicate that a broader market-based approach to greenhouse gas reduction would be less costly and more effective, regulatory approaches have found greater political success. Vehicle efficiency standards have a long history in the U.S and elsewhere, and the recent success of shale gas in the U.S. leads to a focus on coal–gas fuel switching as a way to reduce power sector emissions. We evaluate a global regulatory regime that replaces coal with natural gas in the electricity sector and imposes technically achievable improvements in the efficiency of personal transport vehicles. Its performance and cost are compared with other scenarios of future policy development including a no policy world, achievements under the Copenhagen accord, and a price-based policy to reduce global emissions by 50% by 2050. The assumed regulations applied globally achieve a global emissions reduction larger than projected for the Copenhagen agreements, but they do not prevent global GHG emissions from continuing to grow, and the reduction in emissions is achieved at a high cost compared to a price-based policy. Diagnosis of the reasons for the limited yet high-cost performance reveals influences including the partial coverage of emitting sectors, small or no influence on the demand for emissions-intensive products, leakage when a reduction in fossil use in the covered sectors lowers the price to others, and the partial coverage of GHGs.

The Association of Large-Scale Climate Variability and Teleconnections on Wind Energy Resource over Europe and its Intermittency

2013-09-01T00:00:00Z

The Association of Large-Scale Climate Variability and Teleconnections on Wind Energy Resource over Europe and its Intermittency Kriesche, Pascal; Schlosser, C. Adam In times of increasing importance of wind power in the world’s energy mix, this study focuses on a better understanding of the influences of large-scale climate variability on wind power resource over Europe. The impact of the North Atlantic Oscillation (NAO), the Arctic Oscillation (AO), the El Niño Southern Oscillation (ENSO) and the Atlantic Multidecadal Oscillation (AMO) are investigated in terms of their correlation with wind power density (WPD) at 80 m hub height. These WPDs are calculated based on the MERRA Reanalysis data set covering 31 years of measurements. Not surprisingly, AO and NAO are highly correlated with the time series of WPD. This correlation can also be found in the first principal component of a Principal Component Analysis (PCA) of WPD over Europe explaining 14% of the overall variation. Further, cross-correlation analyses indicates the strongest associated variations are achieved with AO/NAO leading WPD by at most one day. Furthermore, the impact of high and low phases of the respective oscillations has been assessed to provide a more comprehensive illustration. The fraction of WPD for high and low AO/NAO increases considerably for northern Europe, whereas the opposite pattern can be observed for southern Europe. Similar results are obtained by calculating the energy output of three hypothetical wind turbines for every grid point over Europe. Thus, we identified a high interconnection potential between wind farms in order to reduce intermittency, one of the primary challenges in wind power generation. In addition, we observe significant correlations between WPD and AMO.

The Energy and Economic Impacts of Expanding International Emissions Trading

2013-08-21T00:00:00Z

The Energy and Economic Impacts of Expanding International Emissions Trading Qi, Tianyu; Winchester, Niven; Karplus, Valerie; Zhang, Xiliang Emissions trading systems are recognized as a cost-effective way to facilitate emissions abatement and are expected to play an important role in international cooperation for global climate mitigation. Starting from the planned linkage of the European Union’s Emissions Trading System with a new system in Australia in 2015, this paper simulates the impacts of expanding this international emissions market to include China and the US, which are respectively the largest and second largest carbon dioxide (CO2) emitters in the world. We find that including China and the US significantly impacts the price and the quantity of permits traded internationally. China exports emissions rights while other regions import permits. When China joins the EU-Australia/New Zealand (EU-ANZ) linked market, we find that the prevailing global carbon market price falls significantly, from $33 per ton of carbon dioxide (tCO2) to $11.2/tCO2. By contrast, adding the US to the EU-ANZ market increases the price to $46.1/tCO2. If both China and the US join the linked market, the market price of an emissions permit is $17.5/tCO2 and 608 million metric tons (mmt) are traded, compared to 93 mmt in the EU-ANZ scenario. The US and Australia would transfer, respectively, 55% and 78% of their domestic reduction burden to China (and a small amount to the EU) in return for a total transfer payment of $10.6 billion. International trading of emissions permits also leads to a redistribution of renewable energy production. When permit trading between all regions is considered, relative to when all carbon markets operate in isolation, renewable energy in China expands by more than 20% and shrinks by 48% and 90% in, respectively, the US and Australia-New Zealand. In all scenarios, global emissions are reduced by around 5% relative to a case without climate policies.

Limited Sectoral Trading between the EU ETS and China

2013-08-21T00:00:00Z

Limited Sectoral Trading between the EU ETS and China Gavard, Claire; Winchester, Niven; Paltsev, Sergey In the negotiations of the United Nations Framework Convention on Climate Change (UNFCCC), new market mechanisms are proposed to involve Non-Annex I countries in the carbon markets developed by Annex I countries, beyond their current involvement through the Clean Development Mechanism (CDM). Sectoral trading is one such mechanism. It would consist of coupling one economic sector of a Non-Annex I country, e.g., the Chinese electricity sector, with the carbon market of some Annex I countries, e.g., the European Union Emission Trading Scheme (EU ETS). Previous research analyzed the potential impacts of such a mechanism and concluded that a limit would likely be set on the amount of carbon permits that could be imported from the non-Annex I country to the Annex I carbon market, should such a mechanism come into effect. This paper analyzes the impact of limited trading in carbon permits between the EU ETS and Chinese electricity sector when the latter is constrained by a 10% emissions reduction target below business as usual by 2030. The limit on the amount of Chinese carbon permits that could be sold into the European carbon market is modeled through the introduction of a trade certificate system. The analysis employs the MIT Emissions Prediction and Policy Analysis (EPPA) model and takes into account the banking–borrowing of allowances and the inclusion of aviation emissions in the EU ETS. We find that if the amount of permits that can be imported from China to Europe is 10% of the total amount of European allowances, the European carbon price decreases by 34%, while it decreases by 74 % when sectoral trading is not limited. As a consequence, limited sectoral trading does not reverse the changes initiated in the European electricity sector as much as unlimited sectoral trading would. We also observe that international leakage and leakage to non-electricity sectors in China are lower under limited sectoral trading, thus achieving more emissions reductions at the aggregate level. Finally, we find that, if China can capture the rents due to the limit on sectoral trading, it is possible to find a limit that makes both regions better off relative to when there is no international trade in carbon permits.

What GHG Concentration Targets are Reachable in this Century?

2013-07-26T00:00:00Z

What GHG Concentration Targets are Reachable in this Century? Paltsev, Sergey; Reilly, John M.; Sokolov, Andrei We offer simulations that help to understand the relationship between GHG emissions and concentrations, and the relative role of long-lived (e.g., CO2) and short-lived (e.g., CH4) emissions. We show that, absent technologies to remove CO2 from the atmosphere, the 350 CO2 ppm target is out of reach in this century, even if all emissions drop to zero almost immediately (i.e. in 2015). A 350 ppm CO2-equivalent target is potentially achievable, but would require CH4 concentrations falling below preindustrial levels, and thus elimination of emissions from human activities such as rice and livestock agriculture. More realistically, even some of the most aggressive targets proposed through 2035 would lead to concentrations (CO2 or CO2-eq) in the 415–450 ppm range. This is only feasible if after 2035 emissions continued a downward path toward zero. Only in these cases would the temperature target of no more than 2 °C above preindustrial be achieved, and only after peaking above that level before declining.

Implications of Climate Science for Policy

2013-07-18T00:00:00Z

Implications of Climate Science for Policy Jacoby, H.D. Climate change presents the greatest challenge ever faced by our domestic and international institutions, and a great deal of the difficulty lies in the science of the issue. Because human influence on global climate differs in important ways from other environmental threats these peculiarities set the context for discussion of what can be done to reduce greenhouse gas emissions and to adapt to change that cannot be avoided. Following a brief summary of current understanding of how Earth’s climate works, five ways are presented by which the science of climate impinges on attempts to construct a policy response.

Probabilistic Projections of 21st Century Climate Change over Northern Eurasia

2013-07-18T00:00:00Z

Probabilistic Projections of 21st Century Climate Change over Northern Eurasia Monier, Erwan; Sokolov, Andrei; Schlosser, Adam; Scott, Jeffery; Gao, Xiang We present probabilistic projections of 21st century climate change over Northern Eurasia using the Massachusetts Institute of Technology (MIT) Integrated Global System Model (IGSM), an integrated assessment model that couples an earth system model of intermediate complexity with a two-dimensional zonal-mean atmosphere, to a human activity model. Regional climate change is obtained by two downscaling methods: a dynamical downscaling, where the IGSM is linked to a three-dimensional atmospheric model; and a statistical downscaling, where a pattern scaling algorithm uses climate-change patterns from 17 climate models. This framework allows for key sources of uncertainty in future projections of regional climate change to be accounted for: emissions projections; climate system parameters (climate sensitivity, strength of aerosol forcing and ocean heat uptake rate); natural variability; and structural uncertainty. Results show that the choice of climate policy and the climate parameters are the largest drivers of uncertainty. We also find that different initial conditions lead to differences in patterns of change as large as when using different climate models. Finally, this analysis reveals the wide range of possible climate change over Northern Eurasia, emphasizing the need to consider all sources of uncertainty when modeling climate impacts over Northern Eurasia.

Climate Change Impacts on Extreme Events in the United States: An Uncertainty Analysis

2013-05-01T00:00:00Z

Climate Change Impacts on Extreme Events in the United States: An Uncertainty Analysis Monier, Erwan; Gao, Xiang Extreme weather and climate events, such as heat waves, droughts and severe precipitation events, have substantial impacts on ecosystems and the economy. However, future climate simulations display large uncertainty in mean changes. As a result, the uncertainty in future changes of extreme events, especially at the local and national level, is large. In this study, we analyze changes in extreme events over the US in a 60-member ensemble simulation of the 21st century with the Massachusetts Institute of Technology (MIT) Integrated Global System Model–Community Atmosphere Model (IGSM-CAM). Four values of climate sensitivity, three emissions scenarios and five initial conditions are considered. The results show a general intensification of extreme daily maximum temperatures and extreme precipitation events over most of the US. The number of rain days per year increases over the Great Plains but decreases in the northern Pacific Coast and along the Gulf Coast. Extreme daily minimum temperatures increase, especially over the northern parts of the US. As a result, the number of frost days per year decreases over the entire US and the frost-free zone expands northward. This study displays a wide range of future changes in extreme events in the US, even simulated by a single climate model. Nonetheless, it clearly shows that under a reference emissions scenario with no climate policy, changes in extreme events reach dangerous levels, especially for large values of climate sensitivity. On the other hand, the implementation of a stabilization scenario drastically reduces the changes in extremes, even for the highest climate sensitivity considered.

A Framework for Modeling Uncertainty in Regional Climate Change

2013-05-01T00:00:00Z

A Framework for Modeling Uncertainty in Regional Climate Change Monier, Erwan; Gao, Xiang; Scott, Jeffery; Sokolov, Andrei; Schlosser, C. Adam In this study, we present a new modeling framework and a large ensemble of climate projections to investigate the uncertainty in regional climate change over the US associated with four dimensions of uncertainty. The sources of uncertainty considered in this framework are the emissions projections (using different climate policies), climate system parameters (represented by different values of climate sensitivity and net aerosol forcing), natural variability (by perturbing initial conditions) and structural uncertainty (using different climate models). The modeling framework revolves around the Massachusetts Institute of Technology (MIT) Integrated Global System Model (IGSM), an integrated assessment model with an intermediate complexity earth system model (with a two-dimensional zonal-mean atmosphere). Regional climate change over the US is obtained through a two-pronged approach. First, we use the IGSM-CAM framework which links the IGSM to the National Center for Atmospheric Research (NCAR) Community Atmosphere Model (CAM). Secondly, we use a pattern-scaling method that extends the IGSM zonal mean based on climate change patterns from various climate models. Results show that uncertainty in temperature changes are mainly driven by policy choices and the range of climate sensitivity considered. Meanwhile, the four sources of uncertainty contribute more equally to precipitation changes, with natural variability having a large impact in the first part of the 21st century. Overall, the choice of policy is the largest driver of uncertainty in future projections of climate change over the US.

Integrated Economic and Climate Projections for Impact Assessment

2013-05-01T00:00:00Z

Integrated Economic and Climate Projections for Impact Assessment Paltsev, Sergey; Monier, Erwan; Scott, Jeffery; Sokolov, Andrei; Reilly, John M. We designed scenarios for impact assessment that explicitly address policy choices and uncertainty in climate response. Economic projections and the resulting greenhouse gas emissions for the “no climate policy” scenario and two stabilization scenarios: at 4.5 W/m2 and 3.7 W/m2 by 2100 are provided. They can be used for a broader climate impact assessment for the US and other regions, with the goal of making it possible to provide a more consistent picture of climate impacts, and how those impacts depend on uncertainty in climate system response and policy choices. The long-term risks, beyond 2050, of climate change can be strongly influenced by policy choices. In the nearer term, the climate we will observe is hard to influence with policy, and what we actually see will be strongly influenced by natural variability and the earth system response to existing greenhouse gases. In the end, the nature of the system is that a strong effect of policy, especially directed toward long-lived GHGs, will lag by 30 to 40 years its implementation.

The Energy and CO2 Emissions Impact of Renewable Energy Development in China

2013-04-01T00:00:00Z

The Energy and CO2 Emissions Impact of Renewable Energy Development in China Zhang, X.; Qi, T.; Karplus, V.J. China’s recently-adopted targets for developing renewable electricity—wind, solar, and biomass—would require expansion on an unprecedented scale in China and relative to existing global installations. An important question is how far this deployment will go toward achieving China’s low carbon development goals, which include a carbon intensity reduction target of 40–45% relative to 2005 and a non-fossil primary energy target of 15% by 2020. During the period from 2010 to 2020, we find that current renewable electricity targets result in significant additional renewable energy installation and a reduction in cumulative CO2 emissions of 1.2% relative to a no policy baseline. After 2020, the role of renewables is sensitive to both economic growth and technology cost assumptions. Importantly, we find that CO2 emissions reductions due to increased renewables are offset in each year by emissions increases in non-covered sectors through 2050. By increasing reliance on renewable energy sources in the electricity sector, fossil fuel demand in the power sector falls, resulting in lower fossil fuel prices, which in turn leads to greater demand for these fuels in unconstrained sectors. We consider sensitivity to renewable electricity cost after 2020 and find that if cost falls due to policy or other reasons, renewable electricity share increases and results in slightly higher economic growth through 2050. However, regardless of the cost assumption, projected CO2 emissions reductions are very modest under a policy that only targets the supply side in the electricity sector. A policy approach that covers all sectors and allows flexibility to reduce CO2 at lowest cost—such as an emissions trading system—will prevent this emissions leakage and ensure targeted reductions in CO2 emissions are achieved over the long term.

Consumption-Based Adjustment of China's Emissions-Intensity Targets: An Analysis of its Potential Economic Effects

2013-03-01T00:00:00Z

Consumption-Based Adjustment of China's Emissions-Intensity Targets: An Analysis of its Potential Economic Effects Springmann, M.; Zhang, D.; Karplus, V.J. China’s Twelfth Five-Year Plan (2011–2015) aims to achieve a national carbon intensity reduction of 17% through differentiated targets at the provincial level. Allocating the national target among China’s provinces is complicated by the fact that more than half of China’s national carbon emissions are embodied in interprovincial trade, with the relatively developed eastern provinces relying on the central and western provinces for energy-intensive imports. This study develops a consistent methodology to adjust regional emissions-intensity targets for trade-related emissions transfers and assesses its economic effects on China's provinces using a regional computable general equilibrium model of the Chinese economy. This study finds that in 2007 China's eastern provinces outsource 14% of their territorial emissions to the central and western provinces. Adjusting the provincial targets for those emissions transfers increases the reduction burden for the eastern provinces by 60%, while alleviating the burden for the central and western provinces by 50% each. The CGE analysis indicates that this adjustment could double China's national welfare loss compared to the homogenous and politics-based distribution of reduction targets. A shared-responsibility approach that balances production-based and consumption-based emissions responsibilities is found to alleviate those unbalancing effects and lead to a more equal distribution of economic burden among China's provinces.

Protection of Coastal Infrastructure under Rising Flood Risk

2013-03-01T00:00:00Z

Protection of Coastal Infrastructure under Rising Flood Risk Lickley, M.J.; Lin, N.; Jacoby, H.D. The 2005 hurricane season was particularly damaging to the United States, contributing to significant losses to energy infrastructure—much of it the result of flooding from storm surge during hurricanes Katrina and Rita. In 2012, Hurricane Sandy devastated New York City and Northern New Jersey. Research suggests that these events are not isolated, but rather foreshadow a risk that is to continue and likely increase with a changing climate. Extensive energy infrastructure is located along the U.S. Atlantic and Gulf coasts, and these facilities are exposed to an increasing risk of flooding. We study the combined impacts of anticipated sea level rise, hurricane activity and subsidence on energy infrastructure with a first application to Galveston Bay. Using future climate conditions as projected by four different Global Circulation Models (GCMs), we model the change in hurricane activity from present day climate conditions in response to a climate projected in 2100 under the IPCC A1B emissions scenario. We apply the results from hurricane runs from each model to the SLOSH model to investigate the projected change in frequency and distribution of surge heights across climates. Further, we incorporate uncertainty surrounding the magnitude of sea level rise and subsidence, resulting in more detailed projections of risk levels for energy infrastructure over the next century. Applying this model of changing risk exposure, we apply a dynamic programming cost-benefit analysis to the adaptation decision.

Analysis of U.S. Water Resources under Climate Change

2013-02-01T00:00:00Z

Analysis of U.S. Water Resources under Climate Change Blanc, E.; Strzepek, K.; Schlosser, C.A.; Jacoby, H.D.; Gueneau, A.; Fant, C.; Rausch, S.; Reilly, J.M. The MIT Integrated Global System Model (IGSM) framework, extended to include a Water Resource System (WRS) component, is applied to an integrated assessment of effects of alternative climate policy scenarios on U.S. water systems. Climate results are downscaled to yield estimates of surface runoff at 99 river basins of the continental U.S., with an exploration of climate patterns that are relatively wet and dry over the region. These estimates are combined with estimated groundwater supplies. An 11-region economic model (USREP) sets conditions driving water requirements estimated for five use sectors, with detailed sub-models employed for analysis of irrigation and electric power. The water system of the interconnected basins is operated to minimize water stress. Results suggest that, with or without climate change, U.S. average annual water stress is expected to increase over the period 2041 to 2050, primarily because of an increase in water requirements, with the largest water stresses projected in the South West. Policy to lower atmospheric greenhouse gas concentrations has a beneficial effect, reducing water stress intensity and variability in the concerned basins.

Market Cost of Renewable Jet Fuel Adoption in the United States

2013-01-01T00:00:00Z

Market Cost of Renewable Jet Fuel Adoption in the United States Winchester, N.; McConnachie, D.; Wollersheim, C.; Waitz, I.A. The US Federal Aviation Administration (FAA) has a goal that one billion gallons of renewable jet fuel is consumed by the US aviation industry each year from 2018. We examine the cost to US airlines of meeting this goal using renewable fuel produced from a Hydroprocessed Esters and Fatty Acids (HEFA) process from renewable oils. Our approach employs an economy-wide model of economic activity and energy systems and a detailed partial equilibrium model of the aviation industry. If soybean oil is used as a feedstock, we find that meeting the aviation biofuel goal in 2020 will require an implicit subsidy to biofuel producers of $2.69 per gallon of renewable jet fuel. If the aviation goal can be met by fuel from oilseed rotation crops grown on otherwise fallow land, the implicit subsidy is $0.35 per gallon of renewable jet fuel. As commercial aviation biofuel consumption represents less than two per cent of total fuel used by this industry, the goal has a small impact on the average price of jet fuel and carbon dioxide emissions. We also find that, as the product slate for HEFA processes includes diesel and jet fuel, there are important interactions between the goal for renewable jet fuel and mandates for ground transportation fuels.

Analyzing the Regional Impact of a Fossil Energy Cap in China

2013-01-01T00:00:00Z

Analyzing the Regional Impact of a Fossil Energy Cap in China Zhang, D.; Karplus, V.; Rausch, S.; Zhang, X. Decoupling fossil energy demand from economic growth is crucial to China’s sustainable development. In addition to energy and carbon intensity targets enacted under the Twelfth Five-Year Plan (2011–2015), a coal or fossil energy cap is under discussion as a way to constrain the absolute quantity of energy used. Importantly, implementation of such a cap may be compatible with existing policies and institutions. We evaluate the efficiency and distributional implications of alternative energy cap designs using a numerical general equilibrium model of China’s economy, built on the 2007 regional input-output tables for China and the Global Trade Analysis Project global data set. We find that a national cap on fossil energy implemented through a tax on final energy products and an energy saving allowance trading market is the most costeffective design, while a regional coal-only cap is the least cost-effective design. We further find that a regional coal cap results in large welfare losses in some provinces. Capping fossil energy use at the national level is found to be nearly as cost effective as a national CO2 emissions target that penalizes energy use based on carbon content.

Modeling Water Resource Systems under Climate Change: IGSM-WRS

2012-12-01T00:00:00Z

Modeling Water Resource Systems under Climate Change: IGSM-WRS Strzepek, K.; Schlosser, C.A.; Gueneau, A.; Gao, X.; Blanc, É.; Fant, C.; Rasheed, B.; Jacoby, H.D. Through the integration of a Water Resource System (WRS) component, the MIT Integrated Global System Model (IGSM) framework has been enhanced to study the effects of climate change on managed water-resource systems. Development of the WRS involves the downscaling of temperature and precipitation from the zonal representation of the IGSM to regional (latitude-longitude) scale, and the translation of the resulting surface hydrology to runoff at the scale of river basins, referred to as Assessment Sub-Regions (ASRs). The model of water supply is combined with analysis of water use in agricultural and non-agricultural sectors and with a model of water system management that allocates water among uses and over time and routes water among ASRs. Results of the IGSM-WRS framework include measures of water adequacy and ways it is influenced by climate change. Here we document the design of WRS and its linkage to other components of the IGSM, and present tests of consistency of model simulations with the historical record.

Non-Nuclear, Low-Carbon, or Both? The Case of Taiwan

2012-12-01T00:00:00Z

Non-Nuclear, Low-Carbon, or Both? The Case of Taiwan Chen, Y.-H. Henry The Fukushima nuclear accident in Japan has renewed debates on the safety of nuclear power, possibly hurting the role of nuclear power in efforts to limit CO2 emissions. I develop a dynamic economy-wide model of Taiwan with a detailed set of technology options in the power sector to examine the implications of adopting different nuclear power policies on CO2 emissions and the economy. Absent a carbon mitigation target, limiting nuclear power has a small economic cost for Taiwan, but CO2 emissions may increase by more than 3.5% by 2035 when nuclear is replaced by fossil-based generation. With a low-carbon target of a 50% reduction from year 2000 levels by 2050, if the nuclear option and carbon sequestration are not viable, gas-fired power would provide almost 90% of electricity output due to the limited renewable resources. In particular, wind power would account for 1.6% to 4.9% of that output, depending on how it relies on other back-up capacities. With both non-nuclear and low-carbon policies, deploying carbon sequestration on fossil-based generation can significantly reduce the negative GDP impact on the economy. Lastly, lowering carbon mitigation costs further is possible with expanded nuclear capacity.

Shale Gas Production: Potential versus Actual GHG Emissions

2012-11-01T00:00:00Z

Shale Gas Production: Potential versus Actual GHG Emissions O'Sullivan, Francis; Paltsev, Sergey Estimates of greenhouse gas (GHG) emissions from shale gas production and use are controversial. Here we assess the level of GHG emissions from shale gas well hydraulic fracturing operations in the United States during 2010. Data from each of the approximately 4,000 horizontal shale gas wells brought online that year is used to show that about 900 Gg CH4 of potential fugitive emissions were generated by these operations, or 228 Mg CH4 per well—a figure inappropriately used in analyses of the GHG impact of shale gas. In fact, along with simply venting gas produced during the completion of shale gas wells, two additional techniques are widely used to handle these potential emissions, gas flaring, and reduced emissions “green” completions. The use of flaring and reduced emission completions reduce the levels of actual fugitive emissions from shale well completion operations to about 216 GgCH4, or 50 Mg CH4 per well, a release substantially lower than several widely quoted estimates. Although fugitive emissions from the overall natural gas sector are a proper concern, it is incorrect to suggest that shale gas-related hydraulic fracturing has substantially altered the overall GHG intensity of natural gas production.

Climate Co-benefits of Tighter SO2 and NOx Regulations in China

2012-10-01T00:00:00Z

Climate Co-benefits of Tighter SO2 and NOx Regulations in China Nam, Kyung-Min; Waugh, Caleb J.; Paltsev, Sergey; Reilly, John M.; Karplus, Valerie J. Air pollution has been recognized as a significant problem in China. In its Twelfth Five Year Plan (FYP), China proposes to reduce SO2 and NOx emissions significantly, and here we investigate the cost of achieving those reductions and the implications of doing so for CO2 emissions. We extend the analysis through 2050, and either hold emissions policy targets at the level specified in the Twelfth FYP, or continue to reduce them gradually. We apply a computable general equilibrium model of the Chinese economy that includes a representation of pollution abatement derived from detailed assessment of abatement technology and costs. We find that China’s SO2 and NOx emissions control targets would have substantial effects on CO2 emissions leading to emissions savings far beyond those we estimate would be needed to meet its CO2 intensity targets. However, the cost of achieving and maintaining the pollution targets can be quite high given the growing economy. In fact, we find that the Twelfth FYP pollution targets can be met while still expanding the use of coal, but if they are, then there is a lock-in effect that makes it more costly to maintain or further reduce emissions. That is, if firms were to look ahead to tighter targets, they would make different technology choices in the near term, largely turning away from increased use of coal immediately.

Will Economic Restructuring in China Reduce Trade-Embodied CO2 Emissions?

2012-10-01T00:00:00Z

Will Economic Restructuring in China Reduce Trade-Embodied CO2 Emissions? Qi, Tianyu; Winchester, Niven; Karplus, Valerie J.; Zhang, Xiliang We calculate CO2 emissions embodied in China’s net exports using a multi-regional input-output database. We find that the majority of China’s export-embodied CO2 is associated with production of machinery and equipment rather than energy-intensive products, such as steel and aluminum. In 2007, the largest net recipients of embodied CO2 emissions from China include the EU (360 million metric tons, mmt), the U.S. (337 mmt), and Japan (109 mmt). Overall, annual CO2 emissions embodied in China’s net exports totaled 1,177 mmt, equal to 22% of China’s total CO2 emissions. We also develop a global general equilibrium model with a detailed treatment of energy and CO2 emissions. We use the model to analyze the impact of a sectoral shift in the Chinese economy away from industry and towards services, both without and with a decrease in China’s trade surplus, and a tax on energy-intensive exports, which reflect policy objectives in China’s Twelfth Five-Year Plan (2011–2015). We find that without a decrease in the trade surplus, both policies will have a limited impact on China’s net exports of embodied CO2 emissions. The policies have an even smaller effect on global emissions, as reduced production in China is partially offset by increased production elsewhere.

The Future Energy and GHG Emissions Impact of Alternative Personal Transportation Pathways in China

2012-10-01T00:00:00Z

The Future Energy and GHG Emissions Impact of Alternative Personal Transportation Pathways in China Kishimoto, P.N.; Paltsev, S.; Karplus, V.J. A major uncertainty in future energy and greenhouse gas (GHG) emissions projections for China is the evolution of demand for personal transportation modes. This paper explores the implications of divergent personal transportation scenarios, either favoring private vehicles, or emphasizing a sector including all purchased transport (including local public transit, rail and aviation) as substitute for vehicle travel. Motivated by a wide range of forecasts for transport indicators in the literature, we construct plausible scenarios with low-, medium- and high-transport demand growth, and implement them in a technology-rich model which represents opportunities for fuel economy improvement and switching to plug-in hybrid-electric vehicles (PHEVs). The analysis compares primary energy use and GHG emissions in China in the absence and presence of climate policies. We find that a policy that extends the current Chinese emissions-intensity goals through 2050 mostly affects other sectors with lower abatement costs, and so only lightly engages household transport, permitting nearly the same large increases in refined oil demand (by more than five times) and private vehicle stocks (to 430–500 million) as in the reference case. A stringent climate stabilization policy affects household transport, limiting vehicle ownership and petroleum demand, but drives up the share of household spending on transport, and carries high economy-wide costs. The large projected scale of vehicle fleets, refined oil use and transport purchases all suggest that the rate and type of travel demand growth deserves attention by policymakers, as China seeks to address its energy, environmental, and economic goals.

CLM-AG: An Agriculture Module for the Community Land Model version 3.5

2012-09-01T00:00:00Z

CLM-AG: An Agriculture Module for the Community Land Model version 3.5 Gueneau, Arthur; Schlosser, C. Adam; Strzepek, Kenneth M.; Gao, Xiang; Monier, Erwan It is estimated that 40% of all crops grown in the world today are grown using irrigation. As a consequence, shifting precipitation patterns due to climate change are viewed as a major threat to food security. This report presents the Community Land Model-Agriculture module (CLM-AG), which models crop growth and water stress. The CLM-AG model is a global generic crop model built in the framework of the Community Land Model version 3.5. This report describes the structure and main routines of the model. Two different evaluations of the model are then considered. First, at a global level, CLM-AG is run under a historic climatology and compared to the Global Agro-Ecological Zones, an existing model of irrigation need. Second, the irrigation need computed for the United States is compared to survey data from the United States Department of Agriculture. For both evaluations, CLM-AG results are comparable to either the model results or the surveyed data.

Quantifying Regional Economic Impacts of CO2 Intensity Targets in China

2012-09-01T00:00:00Z

Quantifying Regional Economic Impacts of CO2 Intensity Targets in China Zhang, Da; Rausch, Sebastian; Karplus, Valerie; Zhang, Xiliang To address rising energy use and CO2 emissions, China’s leadership has enacted energy and CO2 intensity targets under the Twelfth Five-Year Plan (2011–2015), which are defined at both the national and provincial levels. We develop a computable general equilibrium (CGE) model with global coverage that disaggregates China’s 30 provinces and includes energy system detail, and apply it to assess the impact of provincial CO2 emissions intensity targets. We compare the impact of the provincial targets approach to a single national target for China that achieves the same reduction in CO2 emissions intensity at the national level. We find that at the national level, the national target results in 25% lower welfare loss relative to the provincial targets approach. Given that the regional distribution of impacts has been an important consideration in the target-setting process, we focus on the changes in provincial level CO2 emissions intensity, CO2 emissions, energy consumption, and economic welfare. We observe significant heterogeneity across provinces in terms of the energy system response as well as the magnitude and sometimes sign of welfare impacts. We further model the current policy of fixed end-use electricity prices in China and find that national welfare losses increase. Assumptions about capital mobility have a substantial impact on national welfare loss, while assumptions about natural gas resource potential does not have a large effect.

Carbon Tax Revenue and the Budget Deficit: A Win-Win-Win Solution?

2012-08-01T00:00:00Z

Carbon Tax Revenue and the Budget Deficit: A Win-Win-Win Solution? Rausch, Sebastian; Reilly, John Bush-era tax cuts are scheduled to expire at the end of 2012, leading to interest in raising revenue through a carbon tax. This revenue could be used to either cut other taxes or to avoid cuts in Federal programs. There is a body of economic research suggesting that such an arrangement could be a win-win-win situation. The first win—Congress could reduce personal or corporate income tax rates, extend the payroll tax cut, maintain spending on social programs, or some combination of these options. The second win—these cuts in income taxes would spur the economy, encouraging more private spending and hence more employment and investment. The third win—carbon dioxide (CO2) pollution and oil imports would be reduced. This analysis uses the MIT U.S. Regional Energy Policy (USREP) model to evaluate the effect of a carbon tax as part of a Federal budget deal. A baseline scenario where temporary payroll cuts and the Bush tax cuts are allowed to expire is compared to several scenarios that include a carbon tax starting at $20 per ton in 2013 and rising at 4%. We find that, whether revenue is used to cut taxes or to maintain spending for social programs, the economy is better off with the carbon tax than if taxes remain high to maintain Federal revenue. We also find that, in addition to economic benefits, a carbon tax reduces carbon dioxide emissions to 14% below 2006 levels by 2020, and 20% below by 2050. Oil imports remain at about today’s level, and compared to the case with no carbon tax, are 10 million barrels per day less in 2050. The carbon tax would shift the market toward renewables and other low carbon options, and make the purchase of more fuel-efficient vehicles more economically desirable.

Impacts of Land Use and Biofuels Policy on Climate: Temperature and Localized Impacts

2012-08-06T00:00:00Z

Impacts of Land Use and Biofuels Policy on Climate: Temperature and Localized Impacts Hallgren, Willow; Schlosser, Adam; Monier, Erwan The impact on climate of future land use and energy policy scenarios is explored using two landuse frameworks: (i) Pure Cost Conversion Response (PCCR), or 'extensification', where the price of land is the only constraint to convert land to agricultural production, including growing biofuels, and (ii) Observed Land Supply Response (OLSR), or 'intensification', where legal, environmental and other constraints encourage more intense use of existing managed land. These two land-use frameworks, involving different economic assumptions, were used to explore how the large-scale plantation of cellulosic biofuels to meet global energy demand impacts the future climate. The land cover of the Community Atmospheric Model Version 3.0 (CAM3.0) was manipulated to reflect these two different land use and energy scenarios (i.e. biofuels and no biofuels). Using these landscapes, present and future climate conditions were simulated to assess the land cover impact. In both the intensification and extensification scenarios, the biofuel energy policy increases the land reflectivity of many areas of the globe, indicating that biofuel cropland is replacing darker land-vegetation, which directly leads to cooling. Moreover, the extensification framework—which involves more deforestation than the intensification framework—leads to larger increases in the reflectivity of the Earth's surface and thus a stronger cooling of the land surface in the extratropics. However, the deforestation which occurred in the tropics produced an increase in temperature due to a decrease in evaporative cooling and cloud cover, and an increase in insolation and sensible heating of the near surface. Nevertheless, these surface-air temperature changes associated with land use are smaller than the effect from changes in the trace-gas forcing (i.e. the enhanced greenhouse effect), although over some regions the land-use change can be large enough to counteract the human-induced, radiatively forced warming. A comparison of these biogeophysical impacts on climate of the land use and biofuel policies with the previously published biogeochemical impact of biofuels indicates the dominance of biogeophysical impacts at 2050. http://globalchange.mit.edu/research/publications/reports

The Economic, Energy, and GHG Emissions Impacts of Proposed 2017–2025 Vehicle Fuel Economy Standards in the United States

2012-07-31T00:00:00Z

The Economic, Energy, and GHG Emissions Impacts of Proposed 2017–2025 Vehicle Fuel Economy Standards in the United States Karplus, Valerie; Paltsev, Sergey Increases in the U.S. Corporate Average Fuel Economy (CAFE) Standards for 2017 to 2025 model year light-duty vehicles are currently under consideration. This analysis uses an economy-wide model with detail in the passenger vehicle fleet to evaluate the economic, energy use, and greenhouse gas (GHG) emissions impacts associated with year-on-year increases in new vehicle fuel economy targets of 3%, 4%, 5%, or 6%, which correspond to the initially proposed rates of increase for the 2017 to 2025 CAFE rulemaking. We find that across the range of targets proposed, the average welfare cost of a policy constraint increases non-linearly with target stringency, because the policy targets proposed require increasingly costly changes to vehicles in the near term. Further, we show that the economic and GHG emissions impacts of combining a fuel tax with fuel economy standards could be positive or negative, depending on underlying technology costs. We find that over the period 2015 to 2030, a 5% CAFE policy would reduce gasoline use by about 25 billion gallons per year, reduce CO2 emissions by approximately 190 million metric tons per year, and cost $25 billion per year (net present value in 2004 USD), relative to a No Policy baseline.

Distributional and Efficiency Impacts of Clean and Renewable Energy Standards for Electricity

2012-07-17T00:00:00Z

Distributional and Efficiency Impacts of Clean and Renewable Energy Standards for Electricity Rausch, Sebastian; Mowers, Matthew We examine the efficiency and distributional impacts of greenhouse gas policies directed toward the electricity sector in a model that links a “top-down” general equilibrium representation of the U.S. economy with a “bottom-up” electricity-sector dispatch and capacity expansion model. Our modeling framework features a high spatial and temporal resolution of electricity supply and demand, including renewable energy resources and generating technologies, while representing CO2 abatement options in non-electric sectors as well as economy-wide interactions. We find that clean and renewable energy standards entail substantial efficiency costs compared to an economy-wide carbon pricing policy such as a cap-and-trade program or a carbon tax, and that these policies are regressive across the income distribution. The geographical distribution of cost is characterized by high burdens for regions that depend on non-qualifying generation fuels, primarily coal. Regions with abundant hydro power and wind resources, and a relatively clean generation mix in the absence of policy, are among the least impacted. An important shortcoming of energy standards vis-`a-vis a first-best carbon pricing policy is that no revenue is generated that can be used to alter unintended distributional consequences. http://globalchange.mit.edu/research/publications/reports/all

Cap-and-Trade Climate Policies with Price-Regulated Industries: How Costly are Free Allowances?

2012-07-10T00:00:00Z

Cap-and-Trade Climate Policies with Price-Regulated Industries: How Costly are Free Allowances? Bruno, Lanz, 1980-; Rausch, Sebastian We examine the impacts of alternative cap-and-trade allowance allocation designs in a model of the U.S. economy where price-regulated electric utilities generate 30% of total CO2 emissions. Our empirical model embeds a generator-level description of electricity production—comprising all 16,891 electricity generators in the contiguous U.S.—in a multi-region multi-sector general equilibrium framework that features regulated monopolies and imperfectly competitive wholesale electricity markets. The model recognizes the considerable heterogeneity among households incorporating all 15,588 households from the Consumer and Expenditure Survey as individual agents in the model. Depending on the stringency of the policy, we find that distributing emission permits freely to regulated utilities increases welfare cost by 40- 80% relative to an auction if electricity rates do not reflect the opportunity costs of permits. Despite an implicit subsidy to electricity prices, efficiency costs are disproportionately borne by households in the lowest income deciles. http://globalchange.mit.edu/research/publications/reports/all

An Integrated Assessment Framework for Uncertainty Studies in Global and Regional Climate Change: The IGSM-CAM

2012-06-18T00:00:00Z

An Integrated Assessment Framework for Uncertainty Studies in Global and Regional Climate Change: The IGSM-CAM Monier, Erwan; Scott, Jeffery R.; Sokolov, Andrei P.; Forest, Chris E.; Schlosser, C. Adam This paper describes an integrated assessment framework for uncertainty studies in global and regional climate change. In this framework, the Massachusetts Institute of Technology (MIT) Integrated Global System Model (IGSM), an integrated assessment model that couples an earth system model of intermediate complexity to a human activity model, is linked to the National Center for Atmospheric Research (NCAR) Community Atmosphere Model (CAM). Since the IGSM-CAM incorporates a human activity model, it is possible to analyze uncertainties in emissions resulting from uncertainties intrinsic to the economic model, from parametric uncertainty to uncertainty in future climate policies. Another major feature is the flexibility to vary key climate parameters controlling the climate response: climate sensitivity, net aerosol forcing and ocean heat uptake rate. Thus, the IGSM-CAM is a computationally efficient framework to explore the uncertainty in future global and regional climate change due to uncertainty in the climate response and projected emissions. This study further presents 21st century simulations based on two emissions scenarios (unconstrained scenario and stabilization scenario at 660 ppm CO2-equivalent by 2100) and three sets of climate parameters. The chosen climate parameters provide a good approximation for the median, and the 5th and 95th percentiles of the probability distribution of 21st century climate change. As such, this study presents new estimates of the 90% probability interval of regional climate change for different emissions scenarios. These results underscore the large uncertainty in regional climate change resulting from uncertainty in climate parameters and emissions, and the statistical uncertainty due to natural variability. http://globalchange.mit.edu/research/publications

Modeling Water Withdrawal and Consumption for Electricity Generation in the United States

2012-06-15T00:00:00Z

Modeling Water Withdrawal and Consumption for Electricity Generation in the United States Strzepek, Kenneth M.; Baker, Jonathan; Farmer, William; Schlosser, C. Adam Water withdrawals for thermoelectric cooling account for a significant portion of total water use in the United States. Any change in electrical energy generation policy and technologies has the potential to have a major impact on the management of local and regional water resources. In this report, a model of Withdrawal and Consumption for Thermo-electric Systems (WiCTS) is formalized. This empirically-based framework employs specific water-use rates that are scaled according to energy production, and thus, WiTCS is able to estimate regional water withdrawals and consumption for any electricity generation portfolio. These terms are calculated based on water withdrawal and consumption data taken from the United States Geological Survey (USGS) inventories and a recent NREL report. To illustrate the model capabilities, we assess the impact of a high-penetration of renewable electricity-generation technologies on water withdrawals and consumption in the United States. These energy portfolio scenarios are taken from the Renewable Energy Futures (REF) calculations performed by The U.S. National Renewable Energy Laboratory (NREL) of the U.S. Department of Energy (DOE). Results of the model indicate that significant reductions in water use are achieved under the renewable technology portfolio. Further experiments illustrate additional capabilities of the model. We investigate the impacts of assuming geothermal and concentrated solar power technologies employing wet cooling systems versus dry as well as assuming all wet cooling technologies use closed cycle cooling technologies. Results indicate that water consumption and withdrawals increase under the first assumption, and that water consumption increases under the second assumption while water withdrawals decrease. http://globalchange.mit.edu/research/publications

Green Growth and the Efficient Use of Natural Resources

2012-06-14T00:00:00Z

Green Growth and the Efficient Use of Natural Resources Reilly, John The relatively new concept of "green growth" can be fruitfully connected to concepts and theories in neoclassical economics including market externalities, Ricardian and Hotelling rents, and policies that would correct externalities such as Pigovian taxes or a cap and trade system set to achieve emissions reductions consistent with cost benefit assessment. Partial equilibrium concepts have been extended to general equilibrium models, including their realization in relatively detailed empirical models that faithfully adhere to theoretical concepts of neoclassical economics. With such models we are then able to see how resource depletion and environmental degradation are affecting the economy, and how efforts to reduce the impact of these environmental and resource constraints could improve economic growth and performance. The foundation for traditional computable general equilibrium models are the National Income and Product Accounts (NIPAs), input-output (I-O) tables, and expanded Social Accounting Matrices (SAMs). The basis for extending these to include environmental and resource assets and goods are so called Integrated Economic and Environmental Social Accounts (IEESAs). While environmental effects are often considered to be "non-market," many of the impacts of environment are often reflected in market accounts through damages that might include, for example, less labor (due to environment related health problems), reduced productivity of agroecosystems, or damage to infrastructure and other produced assets. The challenge is to make the environmental connection explicit so as to provide a guide to where changes in policies could provide benefit. However, some damages do not enter the accounts at all, and mainly this is because household labor and leisure time are generally not valued in traditional accounts. Hence the cost of illness in terms of reduced ability to contribute to household activities would be missed in the standard accounts. While the theoretical structure for expanding the accounts has been laid out in various reviews, the empirical challenge of doing so is substantial. Careful attention to expanding NIPA accounts, making it a regular part of government statistical agencies’ efforts would improve the foundation for analysis of potential "green growth" policies and measures. http://globalchange.mit.edu/research/publications/reports

Leackage from Sub-national Climate Initiatives: The Case of California

2012-05-29T00:00:00Z

Leackage from Sub-national Climate Initiatives: The Case of California Caron, Justin; Rausch, Sebastian; Winchester, Niven With federal policies to curb greenhouse gas emissions in the U.S. stagnating, California has taken action on its own. We estimate the impact of California’s cap-and-trade program on the leakage of emissions to other regions using a calibrated general equilibrium model. Sub-national policies can lead to high leakage rates as state economies are generally closely connected to other economies, including integration of electricity markets. Measures that will prevent leakage from California’s cap-and-trade program include requiring permits to be surrendered for emissions embodied in imported electricity and legislation banning “resource shuffling”. Under a cap-and-trade policy without measures to reduce leakage, the price of emission permits is $12 per ton of CO2 and emissions in other regions increase by 46% of the reduction in emissions in California. When imported electricity is included in the program and resource shuffling is banned, the carbon price is $65, there is negative leakage to regions exporting electricity to California, positive leakage to other regions and the overall leakage rate is 2%. We conclude that although there is potential for large increases in emissions elsewhere due to California’s cap-and-trade policy, enforcement of requirements for imported electricity will be effective at curtailing leakage. http://globalchange.mit.edu/research/publications/2286

Valuing Climate Impacts in Integrated Assessment Models: The MIT IGSM

2012-05-22T00:00:00Z

Valuing Climate Impacts in Integrated Assessment Models: The MIT IGSM Reilly, John; Paltsev, Sergey; Selin, Noelle E.; Cai, Yongxia; Nam, Kyung-Min; Monier, Erwan; Dutkiewicz, Stephanie; Scott, Jeffrey; Webster, Mort; Sokolov, Andrei; Strzepek, Ken We discuss a strategy for investigating the impacts of climate change on Earth’s physical, biological and human resources and links to their socio-economic consequences. The features of the integrated global system framework that allows a comprehensive evaluation of climate change impacts are described with particular examples of effects on agriculture and human health. We argue that progress requires a careful understanding of the chain of physical changes—global and regional temperature, precipitation, ocean acidification and polar ice melting. We relate those changes to other physical and biological variables that help people understand risks to factors relevant to their daily lives—crop yield, food prices, premature death, flooding or drought events, land use change. Finally, we investigate how societies may adapt, or not, to these changes and how the combination of measures to adapt or to live with losses will affect the economy. Valuation and assessment of market impacts can play an important role, but we must recognize the limits of efforts to value impacts where deep uncertainty does not allow a description of the causal chain of effects that can be described, much less assigned a likelihood. A mixed approach of valuing impacts, evaluating physical and biological effects, and working to better describe uncertainties in the earth system can contribute to the social dialogue needed to achieve consensus—where it is needed—on the level and type of mitigation and adaptation actions that are required. http://globalchange.mit.edu/research/publications/reports/all

Permafrost, Lakes, and Climate-Warming Methane Feedback: What is the Worst We Can Expect?

2012-05-01T00:00:00Z

Permafrost, Lakes, and Climate-Warming Methane Feedback: What is the Worst We Can Expect? Gao, X.; Schlosser, C.A.; Sokolov, A.; Walter Anthony, K.; Zhuang, Q.; Kicklighter, D.W. Permafrost degradation is likely enhanced by climate warming. Subsequent landscape subsidence and hydrologic changes support expansion of lakes and wetlands. Their anaerobic environments can act as strong emission sources of methane and thus represent a positive feedback to climate warming. Using an integrated earth-system model framework, which considers the range of policy and uncertainty in climatechange projections, we examine the influence of near-surface permafrost thaw on the prevalence of lakes, its subsequent methane emission, and potential feedback under climate warming. We find that increases in atmospheric CH4 and radiative forcing from increased lake CH4 emissions are small, particularly when weighed against unconstrained human emissions. The additional warming from these methane sources, across the range of climate policy and response, is no greater than 0.1 C by 2100. Further, for this temperature feedback to be discernable by 2100 would require at least an order of magnitude larger methaneemission response. Overall, the biogeochemical climate-warming feedback from boreal and Arctic lake emissions is relatively small whether or not humans choose to constrain global emissions. http://globalchange.mit.edu/research/publications/2275

Combining a New Vehicle Fuel Economy Standard with a Cap-and-Trade Policy: Energy and Economic Impact in the United States

2012-05-01T00:00:00Z

Combining a New Vehicle Fuel Economy Standard with a Cap-and-Trade Policy: Energy and Economic Impact in the United States Karplus, V.J.; Paltsev, S.; Babiker, M.; Reilly, J.M. The United States has adopted fuel economy standards that require increases in the on-road efficiency of new passenger vehicles, with the goal of reducing petroleum use, as well as (more recently) greenhouse gas (GHG) emissions. Understanding the cost and effectiveness of this policy, alone and in combination with economy-wide policies that constrain GHG emissions, is essential to inform coordinated design of future climate and energy policy. In this work we use a computable general equilibrium model, the MIT Emissions Prediction and Policy Analysis (EPPA) model, to investigate the effect of combining a fuel economy standard with an economy-wide GHG emissions constraint in the United States. First, a fuel economy standard is shown to be at least five to fourteen times less cost effective than a price instrument (fuel tax) when targeting an identical reduction in cumulative gasoline use. Second, when combined with a cap-and-trade (CAT) policy, the fuel economy standard increases the cost of meeting the GHG emissions constraint by forcing expensive reductions in passenger vehicle gasoline use, displacing more cost-effective abatement opportunities. Third, the impact of adding a fuel economy standard to the CAT policy depends on the availability and cost of abatement opportunities in transport—if advanced biofuels provide a cost-competitive, low carbon alternative to gasoline, the fuel economy standard does not bind and the use of low carbon fuels in passenger vehicles makes a significantly larger contribution to GHG emissions abatement relative to the case when biofuels are not available. This analysis underscores the potentially large costs of a fuel economy standard relative to alternative policies aimed at reducing petroleum use and GHG emissions. It also demonstrates the importance of jointly considering the effects of multiple policies aimed at reducing petroleum use and GHG emissions, and the associated economic costs. http://globalchange.mit.edu/research/publications/2271

Applying Engineering and Fleet Detail to Represent Passenger Vehicle Transport in a Computable General Equilibrium Model

2012-04-01T00:00:00Z

Applying Engineering and Fleet Detail to Represent Passenger Vehicle Transport in a Computable General Equilibrium Model Karplus, V.J.; Paltsev, S.; Babiker, M.; Heywood, J.; Reilly, J.M. A well-known challenge in computable general equilibrium (CGE) models is to maintain correspondence between the forecasted economic and physical quantities over time. Maintaining such a correspondence is necessary to understand how economic forecasts reflect, and are constrained by, relationships within the underlying physical system. This work develops a method for projecting global demand for passenger vehicle transport, retaining supplemental physical accounting for vehicle stock, fuel use, and greenhouse gas (GHG) emissions. This method is implemented in the MIT Emissions Prediction and Policy Analysis Version 5 (EPPA5) model and includes several advances over previous approaches. First, the relationship between per-capita income and demand for passenger vehicle transport services (in vehicle-miles traveled, or VMT) is based on econometric data and modeled using quasi-homothetic preferences. Second, the passenger vehicle transport sector is structured to capture opportunities to reduce fleet-level gasoline use through the application of vehicle efficiency or alternative fuel vehicle technologies, introduction of alternative fuels, or reduction in demand for VMT. Third, alternative fuel vehicles (AFVs) are introduced into the EPPA model. Fixed costs as well as learning effects that could affect the rate of AFV introduction are captured explicitly. This model development lays the foundation for assessing policies that differentiate based on vehicle age and efficiency, alter the relative prices of fuels, or focus on promoting specific advanced vehicle or fuel technologies. http://globalchange.mit.edu/research/publications/2270

The Role of China in Mitigating Climate Change

2012-04-01T00:00:00Z

The Role of China in Mitigating Climate Change Paltsev, S.; Morris, J.; Cai, Y.; Karplus, V.; Jacoby, H. We explore short- and long-term implications of several energy scenarios of China’s role in efforts to mitigate global climate risk. The focus is on the impacts on China’s energy system and GDP growth, and on global climate indicators such as greenhouse gas concentrations, radiative forcing, and global temperature change. We employ the MIT Integrated Global System Model (IGSM) framework and its economic component, the MIT Emissions Prediction and Policy Analysis (EPPA) model. We demonstrate that China’s commitments for 2020, made during the UN climate meetings in Copenhagen and Cancun, are reachable at very modest cost. Alternative actions by China in the next 10 years do not yield any substantial changes in GHG concentrations or temperature due to inertia in the climate system. Consideration of the longer-term climate implications of the Copenhagen-type of commitments requires an assumption about policies after 2020, and the effects differ drastically depending on the case. Meeting a 2°C target is problematic unless radical GHG emission reductions are assumed in the short-term. Participation or non-participation of China in global climate architecture can lead by 2100 to a 200–280 ppm difference in atmospheric GHG concentration, which can result in a 1.1°C to 1.3°C change by the end of the century. We conclude that it is essential to engage China in GHG emissions mitigation policies, and alternative actions lead to substantial differences in climate, energy, and economic outcomes. Potential channels for engaging China can be air pollution control and involvement in sectoral trading with established emissions trading systems in developed countries. http://globalchange.mit.edu/research/publications/2265

CliCrop: a Crop Water-Stress and Irrigation Demand Model for an Integrated Global Assessment Model Approach

2012-04-01T00:00:00Z

CliCrop: a Crop Water-Stress and Irrigation Demand Model for an Integrated Global Assessment Model Approach Fant, C.A.; Gueneau, A.; Strzepek, K.; Awadalla, S.; Farmer, W.; Blanc, E.; Schlosser, C.A. This paper describes the use of the CliCrop model in the context of climate change general assessment modeling. The MIT Integrated Global System Model (IGSM) framework is a global integrated assessment modeling framework that uses emission predictions and economic outputs from the MIT Emission Prediction and Policy Analysis (EPPA) model and earth system modeling predictions from the IGSM to drive a land system component, a crop model (CliCrop) and a Water Resource System (WRS) model. The global Agriculture and Water System are dependant upon and interlinked with the global climate system. As irrigated agriculture provides 60% of grains and 40% of all crop production on 20% of global crop lands and accounts for 80% of global water consumption, it is crucial that the agricultural-water linkage be properly modeled. Crop models are used to predict future yields, irrigation demand and to understand the effect of crop and soil type on food productivity and soil fertility. In the context of an integrated global assessment, a crop water-stress and irrigation demand model must meet certain specifications that are different for other crop models; it needs to be global, fast and generic with a minimal set of inputs. This paper describes how CliCrop models the physical and biological processes of crop growth and yield production and its use within the MIT Integrated Global System Model (IGSM) framework, including the data inputs. This paper discusses the global data bases used as input to CliCrop and provides a comparison of the accuracy of CliCrop with the detailed biological-based crop model DSSAT as well as with measured crop yields over the U.S. at the country level using reanalyzed weather data. In both cases CliCrop performed well and the analysis validated its use for climate change impact assessment. We then show why correctly modeling the soil is important for irrigation demand calculation, especially in temperate areas. Finally, we discuss a method to estimate actual water withdrawal from modeled physical crop requirements using U.S. historical data. http://globalchange.mit.edu/research/publications/2264

City-Size Distribution as a Function of Socioeconomic Conditions: An Eclectic Approach to Downscaling Global Population

2012-03-01T00:00:00Z

City-Size Distribution as a Function of Socioeconomic Conditions: An Eclectic Approach to Downscaling Global Population Nam, K.-M.; Reilly, J.M. In this study, we introduce a new method of downscaling global population distribution, for which purpose conventional approaches have serious limitations in application. Our approach is “eclectic,” as it explores the intersection between an optimization framework and the empirical regularities involved in rank-size distributions. The novelty of our downscaling model is that it allows city-size distributions to interact with socioeconomic variables. Our contribution to the urban studies literature is twofold. One is our challenge to the conventional view that the proportionate growth dynamics underlies empirical rank-size regularities. We first show that the city-size distribution of a region can deviate substantially from a log-normal distribution with cross-regional and time variations, and then demonstrate that such variations can be explained by certain socioeconomic conditions that each region confronts at a particular time point. In addition to expanding academic debates on city-size distributions, our study can pave the way for various academic and professional research projects, which need spatial distribution of global population at fine grid cell levels as key input. Our model is applicable to the entire globe, including regions for which reliable sub-regional population data sets are limitedly available, and can be extended easily to function as a forecasting model. http://globalchange.mit.edu/research/publications/2254

Effects of Nitrogen Limitation on Hydrological Processes in CLM4-CN

2012-03-01T00:00:00Z

Effects of Nitrogen Limitation on Hydrological Processes in CLM4-CN Lee, E.; Felzer, B.S. The role of nitrogen limitation on photosynthesis downregulation and stomatal conductance has a significant influence on evapotranspiration and runoff. In the current Community Land Model with coupled Carbon and Nitrogen cycles (CLM4-CN), however, the carbon and water coupling in stomata is not linked to nitrogen limitation. We modify the incomplete linkages between carbon, nitrogen, and water, and examine how nitrogen limitation affects hydrological processes in CLM4-CN. In addition, we evaluate if the modification can improve the simulation of carbon and water fluxes. Applying the effects of nitrogen limitation on stomatal conductance significantly decreases leaf photosynthesis. It leads to a reduction in canopy transpiration, thereby increasing total runoff, mainly due to increasing subsurface runoff. More available soil water for vegetation from the reduced transpiration helps increase gross primary productivity (GPP) in the relatively moisture-limited regions of grassland/steppe and savanna. But, in the tropics and boreal forest regions, changes in soil water by nitrogen limitation are insignificant, and GPP decreases directly by down-regulated leaf photosynthesis. Decreasing canopy transpiration and increasing runoff from nitrogen limitation improve simulating latent heat flux and runoff by reducing high biases for latent heat flux in the tropics and low biases for runoff in the tropics and northern high-latitudes. In addition, the CLM4-CN with leaf-level nitrogen limitation reduces high model biases in tropical GPP. Thus, nitrogen limitation on the leaf-level significantly affects hydrological processes in CLM4-CN and improves the simulation of carbon and water fluxes. http://globalchange.mit.edu/research/publications/2253

Emissions Pricing to Stablize Global Climate

2012-03-01T00:00:00Z

Emissions Pricing to Stablize Global Climate Bosetti, V.; Paltsev, S.; Reilly, J.; Carraro, C. In the absence of significant greenhouse gas (GHG) mitigation, many analysts project that atmospheric concentrations of species identified for control in the Kyoto protocol could exceed 1000 ppm (carbon-dioxide-equivalent) by 2100 from the current levels of about 435 ppm. This could lead to global average temperature increases of between 2.5° and 6° C by the end of the century. There are risks of even greater warming given that underlying uncertainties in emissions projections and climate response are substantial. Stabilization of GHG concentrations that would have a reasonable chance of meeting temperature targets identified in international negotiations would require significant reductions in GHG emissions below “business-as-usual” levels, and indeed from present emissions levels. Nearly universal participation of countries is required, and the needed investments in efficiency and alternative energy sources would entail significant costs. Resolving how these additional costs might be shared among countries is critical to facilitating a wide participation of large-emitting countries in a climate stabilization policy. The 2°C target is very ambitious given current atmospheric concentrations and inertia in the energy and climate system. The Copenhagen pledges for 2020 still keep the 2°C target within a reach, but very aggressive actions would be needed immediately after that. http://globalchange.mit.edu/research/publications/2241

Potential Direct and Indirect Effects of Global Cellulosic Biofuel Production on Greenhouse Gas Fluxes from Future Land-use Chage

2012-03-01T00:00:00Z

Potential Direct and Indirect Effects of Global Cellulosic Biofuel Production on Greenhouse Gas Fluxes from Future Land-use Chage Kicklighter, D.W.; Gurgel, A.; Melillo, J.; Paltsev, S. The production of cellulosic biofuels may have a large influence on future land emissions of greenhouse gases. These effects will vary across space and time depending on land-use policies, trade, and variations in environmental conditions. We link an economic model with a terrestrial biogeochemistry model to explore how projections of cellulosic biofuels production may influence future land emissions of carbon and nitrous oxide. Tropical regions, particularly Africa and Latin America, are projected to become major producers of biofuels. Most biofuels production is projected to occur on lands that would otherwise be used to produce crops, livestock and timber. Biofuels production leads to displacement and a redistribution of global food and timber production along with a reduction in the trade of food products. Overall, biofuels production and the displacement of other managed lands increase emissions of greenhouse gases primarily as a result of carbon emissions from deforestation and nitrous oxide emissions from fertilizer applications to maximize biofuel crop production in tropical regions. With optimal application of nitrogen fertilizers, cellulosic biofuels production may enhance carbon sequestration in soils of some regions. As a result, the relative importance of carbon emissions versus nitrous oxide emissions varies among regions. Reductions in carbon sequestration by natural ecosystems caused by the expansion of biofuels have minor effects on the global greenhouse gas budget and are more than compensated by concurrent biofuel-induced reductions in nitrous oxide emissions from natural ecosystems. Land policies that avoid deforestation and fertilizer applications, particularly in tropical regions, will have the largest impact on minimizing land emissions of greenhouse gas from cellulosic biofuels production. http://globalchange.mit.edu/research/publications/2240

Characterization of Wind Power Resource in the United States and its Intermittency

2011-12-01T00:00:00Z

Characterization of Wind Power Resource in the United States and its Intermittency Gunturu, U.B.; Schlosser, C.A. Wind resource in the continental and offshore United States has been reconstructed and characterized using metrics that describe, apart from abundance, its availability, persistence and intermittency. The Modern Era Retrospective-Analysis for Research and Applications (MERRA) boundary layer flux data has been used to construct wind profile at 50m, 80m, 100m and 120m turbine hub heights. The wind power density estimates at 50m are qualitatively similar to those in the US wind atlas developed by the National Renewable Energy Laboratory (NREL), but quantitatively a class less in some regions, but are within the limits of uncertainty. The wind speeds at 80m were quantitatively and qualitatively close to the NREL wind map. The possible reasons for overestimation by NREL have been discussed. For long tailed distributions like those of the wind power density, the mean is an overestimation and median is suggested for summary representation of the wind resource. The impact of raising the wind turbine hub height on metrics of abundance, persistence, variability and intermittency is analyzed. There is a general increase in availability and abundance of wind resource but the there is an increase in intermittency in terms of level crossing rate in low resource regions. The key aspect of geographical diversification of wind farms to mitigate intermittency - that the wind power generators are statistically independent - is also tested. This condition is found in low resource regions like the east and west coasts. However, in the central US region which has rich resource the condition fails as widespread coherent intermittence in wind power density is found. Thus large regions are synchronized in having wind power or lack thereof. Thus, geographical diversification in this region needs to be planned strategically. The annual distribution of hourly wind power density shows considerable variability and suggests wind floods and droughts that roughly correspond with La-Nina and El-Nino years respectively. The collective behavior of wind farms in seven Independent System Operator (ISO) areas has also been studied. The generation duration curves for each ISO show that there is no aggregated power for some fraction of the time. Aggregation of wind turbines mitigates intermittency to some extent, but each ISO has considerable fraction of time with less than 5% capacity. The hourly wind power time series show benefit of aggregation but the high and low wind events are lumped in time, thus corroborating the result that the intermittency is synchronized. The time series show that there are instances when there is no wind power in most ISOs because of large-scale high pressure systems. An analytical consideration of the collective behavior of aggregated wind turbines shows that the benefit of aggregation saturates beyond ten units. Also, the benefit of aggregation falls rapidly with temporal correlation between the generating units. http://globalchange.mit.edu/research/publications/2221

Influence of Air Quality Model Resolution on Uncertainty Associated With Health Impacts

2011-12-01T00:00:00Z

Influence of Air Quality Model Resolution on Uncertainty Associated With Health Impacts Thompson, T.M.; Selin, N.E. We evaluate the uncertainty associated with regional air quality modeling grid resolution when calculating the health benefits of proposed air quality regulations. Using a regional photochemical model (CAMx), we ran two modeling episodes (a 2006 basecase and a 2018 attainment demonstration, both for Houston, Texas) at 36, 12, 4 and 2 km resolution. The basecase model performance was evaluated for each resolution for both monitor-based and population-weighted calculations of daily maximum 8-hour averaged ozone. Results from each resolution were more similar to each other than they are to actual measured values. However, the model performance improved when population weighted ozone concentration was used as the metric versus the standard daily maximum ozone concentrations at monitor site locations. Then population-weighted ozone concentrations were used to calculate the estimated health impacts of modeled ozone reduction from the basecase to the attainment demonstration including the 95% confidence intervals associated with each impact from concentrationresponse functions. We found that estimated avoided mortalities were not significantly different using coarse resolution, although 36 km resolution may over predict some potential health impacts. Given the cost/benefit analyses requirements of the Clean Air Act, the uncertainty associated with human health impacts and therefore the results reported in this study, we conclude that population weighted ozone concentrations obtained using regional photochemical models at 36 km resolution are meaningful relative to values obtained using fine (12 km or finer) resolution modeling. This result opens up the possibility for uncertainty analyses on 36 km resolution air quality modeling results, which are on average 10 times more computationally efficient. Contents http://globalchange.mit.edu/files/document/MITJPSPGC_Rpt208.pdf

The Influence of Shale gas on U.S. Energy and Environmental Policy

2011-11-01T00:00:00Z

The Influence of Shale gas on U.S. Energy and Environmental Policy Jacoby, H.D.; O'Sullivan, F.M.; Paltsev, S. The emergence of U.S. shale gas resources to economic viability affects the nation’s energy outlook and the expected role of natural gas in climate policy. Even in the face of the current shale gas boom, however, questions are raised about both the economics of this industry and the wisdom of basing future environmental policy on projections of large shale gas supplies. Analysis of the business model appropriate to the gas shales suggests that, though the shale future is uncertain, these concerns are overstated. The policy impact of the shale gas is analyzed using two scenarios of greenhouse gas control—one mandating renewable generation and coal retirement, the other using price to achieve a 50% emissions reduction. The shale gas is shown both to benefit the national economy and to ease the task of emissions control. However, in treating the shale as a “bridge” to a low carbon future there are risks to the development of technologies, like capture and storage, needed to complete the task. http://globalchange.mit.edu/research/publications/2219

Process Modeling of Global Soil Nitrous Oxide Emissions

2011-09-01T00:00:00Z

Process Modeling of Global Soil Nitrous Oxide Emissions Saikawa, E.; Schlosser, C.A.; Prinn, R.G. Nitrous oxide is an important greenhouse gas and is a major ozone-depleting substance. To understand and quantify soil nitrous oxide emissions, we expanded the Community Land Model with prognostic Carbon and Nitrogen (CLM-CN) by inserting a module to estimate annually- and seasonally-varying nitrous oxide emissions between 1978 and 2000. We evaluate our soil N2O emission estimates against existing emissions inventories, other process-based model estimates, and observations from two forest sites in the Amazon and one in the United States. The model reproduces soil temperature and soil moisture relatively well, and it reconfirms the important relationship between N2O emissions and these parameters. The model also reproduces observations of N2O emissions well in the Amazonian forests but not during the winter in the USA. Applying this model to estimate the past 23 years of global soil N2O emissions, we find that there is a significant decrease in soil N2O emissions associated with drought and El Ni˜no years. More study is necessary to quantify the high-latitude winter activity in the model in order to better understand the impact of future climate on N2O emissions and vice versa. http://globalchange.mit.edu/research/publications/2213

Quantifying the Likelihood of Regional Cimate Change: A hybridized Approach

2011-09-01T00:00:00Z

Quantifying the Likelihood of Regional Cimate Change: A hybridized Approach Schlosser, C. Adam; Forest, C.; Awadalla, S.; Farmer, W.; Gao, X.; Strzepek, K. The growing need for risk-based assessments of impacts and adaptation to climate change calls for increased capability in climate projections: the quantification of the likelihood of regional outcomes and the representation of their uncertainty. Herein, we present a technique that extends the latitudinal projections of the 2-D atmospheric model of the MIT Integrated Global System Model (IGSM) by applying longitudinally resolved patterns from observations, and from climate-model projections archived from exercises carried out for the 4th Assessment Report (AR4) of the Intergovernmental Panel on Climate Change (IPCC). The method maps the IGSM zonal means across longitude using a set of transformation coefficients, and we demonstrate this approach in application to near-surface air temperature and precipitation, for which high-quality observational datasets and model simulations of climate change are available. The current climatology of the transformation coefficients is observationally based. To estimate how these coefficients may alter with climate, we characterize the climate models’ spatial responses, relative to their zonal mean, from transient increases in trace-gas concentrations and then normalize these responses against their corresponding transient global temperature responses. This procedure allows for the construction of meta-ensembles of regional climate outcomes, combining the ensembles of the MIT IGSM—which produce global and latitudinal climate projections, with uncertainty, under different global climate policy scenarios—with regionally resolved patterns from the archived IPCC climate-model projections. This approach also provides a hybridization of the climate-model longitudinal projections with the global and latitudinal patterns projected by the IGSM, and can be applied to any given state or flux variable that has the sufficient observational and model-based information.

Implementation of a Cloud Radiative Adjustment Method to Change the Climate Sensitivity of CAM3

2011-08-01T00:00:00Z

Implementation of a Cloud Radiative Adjustment Method to Change the Climate Sensitivity of CAM3 Sokolov, Andrei P.; Monier, Erwan Conducting probabilistic climate projections with a particular climate model requires the ability to vary the model’s characteristics, such as its climate sensitivity. In this study, we implement and validate a method to change the climate sensitivity of the National Center for Atmospheric Research (NCAR) Community Atmosphere Model version 3 (CAM3) through a cloud radiative adjustment. Results show that the cloud radiative adjustment method does not lead to physically unrealistic changes in the model’s response to an external forcing, such as doubling CO2 concentrations or increasing sulfate aerosol concentrations. Furthermore, this method has some advantages compared to the traditional perturbed physics approach. In particular, the cloud radiative adjustment method can produce any value of climate sensitivity within the wide range of uncertainty based on the observed 20th century climate change. As a consequence, this method allows Monte Carlo type probabilistic climate forecasts to be conducted where values of uncertain parameters not only cover the whole uncertainty range, but cover it homogeneously. Unlike the perturbed physics approach which can produce several versions of a model with the same climate sensitivity but with very different regional patterns of change, the cloud radiative adjustment method can only produce one version of the model with a specific climate sensitivity. As such, a limitation of this method is that it cannot cover the full uncertainty in regional patterns of climate change. Abstract and PDF report are also available on the MIT Joint Program on the Science and Policy of Global Change website (http://globalchange.mit.edu/).

Global Aerosol Health Impacts: Quantifying Uncertainties

2011-08-01T00:00:00Z

Global Aerosol Health Impacts: Quantifying Uncertainties Selin, Noelle E.; Paltsev, Sergey; Wang, Chien; Donkelaar, A. van; Martin, R.V. Atmospheric fine particulate matter <2.5 μm (PM2.5) can cause cardiovasculatory and respiratory damages and mortalities. Assessing population exposure to and damages from PM2.5 is important for policy, but measurement networks are only available in a few regions. We assess variation resulting from using different sources of concentration information to constrain PM2.5 exposure worldwide, and compare the magnitude of this variation to uncertainties in epidemiological exposure-response functions and economic valuation of health impacts. We find that only 10% of global population is in areas constrained by ground-based data. We calculate and compare regionally-averaged population-weighted concentrations using two atmospheric models: the MIT/NCAR CAM3 aerosol-climate model, and the GEOS-Chem atmospheric chemistry model; and a satellite-derived PM2.5 product. We examine the contributions of different aerosol components to population-weighted PM2.5, and find large differences in exposure between U.S. and global populations. We use the MIT Emissions Prediction and Policy Analysis Health Effects model (EPPA-HE) to assess global health impacts and related economic costs, and conduct probabilistic uncertainty analysis of concentration-response functions. We use these combined approaches to project uncertainty ranges for health impacts and related economic costs from present-day PM2.5. We find large uncertainties in simulated PM2.5, especially globally; the magnitude of concentration variation among estimation methods is comparable to uncertainties in epidemiological functions and economic valuations. We identify major contributors to concentration variation, notably the parameterization of atmospheric dust. We estimate an annual global welfare cost of present-day (2000-2005) PM2.5 of $US 280 billion (range $120 – 510 billion), and related annual mortalities at 1.3 million per year (630,000 – 2.1 million). Abstract and PDF report are also available on the MIT Joint Program on the Science and Policy of Global Change website (http://globalchange.mit.edu/).

Distributional Impacts of Carbon Pricing: A General Equilibrium Approach with Micro-Data for Households

2011-07-01T00:00:00Z

Distributional Impacts of Carbon Pricing: A General Equilibrium Approach with Micro-Data for Households Rausch, Sebastian; Metcalf, Gilbert E.; Reilly, John M. Many policies to limit greenhouse gas emissions have at their core efforts to put a price on carbon emissions. Carbon pricing impacts households both by raising the cost of carbon intensive products and by changing factor prices. A complete analysis requires taking both effects into account. The impact of carbon pricing is determined by heterogeneity in household spending patterns across income groups as well as heterogeneity in factor income patterns across income groups. It is also affected by precise formulation of the policy (how is the revenue from carbon pricing distributed) as well as the treatment of other government policies (e.g. the treatment of transfer payments). What is often neglected in analyses of policy is the heterogeneity of impacts across households even within income or regional groups. In this paper, we incorporate 15,588 households from the U.S. Consumer and Expenditure Survey data as individual agents in a comparative-static general equilibrium framework. These households are represented within the MIT USREP model, a detailed general equilibrium model of the U.S. economy. In particular, we categorize households by full household income (factor income as well as transfer income) and apply various measures of lifetime income to distinguish households that are temporarily low-income (e.g., retired households drawing down their financial assets) from permanently low-income households. We also provide detailed within-group distributional measures of burden impacts from various policy scenarios. Abstract and PDF report are also available on the MIT Joint Program on the Science and Policy of Global Change website (http://globalchange.mit.edu/).

Russia’s Natural Gas Export Potential up to 2050

2011-07-01T00:00:00Z

Russia’s Natural Gas Export Potential up to 2050 Paltsev, Sergey Recent increases in natural gas reserve estimates and advances in shale gas technology make natural gas a fuel with good prospects to serve a bridge to a low-carbon world. Russia is an important energy supplier as it holds the world largest natural gas reserves and it is the world’s largest exporter of natural gas. Energy was one of the driving forces of Russia’s recent economic recovery from the economic collapse of 1990s. These prospects have changed drastically with a global recession and the collapse of oil and gas prices from their peaks of 2008. An additional factor is an ongoing surge in a liquefied natural gas (LNG) capacity and a development of Central Asia’s and the Middle East gas supplies that can compete with Russian gas in its traditional (European) and potential (Asian) markets. To study the long-term prospects for Russian natural gas, we employ the MIT Emissions Prediction and Policy Analysis (EPPA) model, a computable general equilibrium model of the world economy. While we consider the updated reserve estimates for all world regions, in this paper we focus on the results for Russian natural gas trade. The role of natural gas is explored in the context of several policy assumptions: with no greenhouse gas mitigation policy and scenarios of emissions targets in developed countries. Scenarios where Europe takes on an even more restrictive target of 80 percent reduction of greenhouse gas emissions relative to 2005 by 2050 and reduces its nuclearbased generation are also considered. Asian markets become increasingly important for natural gas exports and several scenarios about their potential development are considered. We found that over the next 20-40 years natural gas can still play a substantial role in Russian exports and there are substantial reserves to support a development of the gas-oriented energy system both in Russia and in its current and potential gas importers. In the Reference scenario, exports of natural gas grow from Russia’s current 7 Tcf to 10-12 Tcf in 2030 and 15-18 Tcf in 2050. Alternative scenarios provide a wider range of projections, with a share of Russian gas exports shipped to Asian markets rising to 30 percent by 2030 and more than 50 percent in 2050. Patterns of international gas trade show increased flows to the Asian region from the Middle East, Central Asia, Australia and Russia. Europe’s reliance on LNG imports increases, while it still maintains sizable imports from Russia. Abstract and PDF report are also available on the MIT Joint Program on the Science and Policy of Global Change website (http://globalchange.mit.edu/).

A Strategy for a Global Observing System for Verification of National Greenhouse Gas Emissions

2011-06-01T00:00:00Z

A Strategy for a Global Observing System for Verification of National Greenhouse Gas Emissions Prinn, Ronald G.; Heimbach, P.; Rigby, Matthew; Dutkiewicz, Stephanie; Melillo, Jerry M.; Reilly, John M.; Kicklighter, David W.; Waugh, Caleb With the risks of climate change becoming increasingly evident, there is growing discussion regarding international treaties and national regulations to lower greenhouse gas (GHG) emissions. Enforcement of such agreements is likely to depend formally upon national and sectoral emission reporting procedures (sometimes referred to as “bottom-up” methods). However, for these procedures to be credible and effective, it is essential that these reports or claims be independently verified. In particular, any disagreements between these “bottom-up” emission estimates, and independent emission estimates inferred from global GHG measurements (so-called “top-down” methods) need to be resolved. Because emissions control legislation is national or regional in nature, not global, it is also essential that “top-down” emission estimates be determined at these same geographic scales. This report lays out a strategy for quantifying and reducing uncertainties in greenhouse gas emissions, based on a comprehensive synthesis of global observations of various types with models of the global cycles of carbon dioxide and other greenhouse gases that include both the natural and human influences on these cycles. The overall goal is to establish a global observing and estimation system that incorporates all relevant available knowledge (physical, biogeochemical, technological and economic) in order to verify greenhouse gas emissions, as a key component of any global GHG treaty. Abstract and PDF report are also available on the MIT Joint Program on the Science and Policy of Global Change website (http://globalchange.mit.edu/).

Future Yield Growth: What Evidence from Historical Data?

2011-05-01T00:00:00Z

Future Yield Growth: What Evidence from Historical Data? Gitiaux, Xavier; Reilly, John M.; Paltsev, Sergey The potential future role of biofuels has become an important topic in energy legislation as it is seen as a potential low carbon alternative to conventional fuels. Hence, future yield growth is an important topic from many perspectives, and given the extensions of the period over which data are available a re-evaluation of yields trends is in order. Our approach is to focus on time series analysis, and to improve upon past work by investigating yields of many major crops in many parts of the world. We also apply time series techniques that allow us to test for the persistence of a plateau pattern that has worried analysts, and that provide a better estimate of forecast uncertainty. The general conclusion from this time series analysis of yields is that casual observation or simple linear regression can lead to overconfidence in projections because of the failure to consider the likelihood of structural breaks. Abstract and PDF report are also available on the MIT Joint Program on the Science and Policy of Global Change website (http://globalchange.mit.edu/).

The Impact of Climate Policy on U.S. Aviation

2011-04-01T00:00:00Z

The Impact of Climate Policy on U.S. Aviation Winchester, Niven; Wollersheim, C.; Clewlow, R.; Jost, N.C.; Paltsev, Sergey; Reilly, John M.; Waitz, I.A. We evaluate the impact of an economy-wide cap-and-trade policy on U.S. aviation taking the American Clean Energy and Security Act of 2009 (H.R.2454) as a representative example. We use an economywide model to estimate the impact of H.R. 2454 on fuel prices and economic activity, and a partial equilibrium model of the aviation industry to estimate changes in aviation carbon dioxide (CO2) emissions and operations. Between 2012 and 2050, with reference demand growth benchmarked to ICAO/GIACC (2009) forecasts, we find that aviation emissions increase by 130%. In our climate policy scenarios, emissions increase by between 97% and 122%. A key finding is that, under the core set of assumptions in our analysis, H.R. 2454 reduces average fleet efficiency, as increased air fares reduce demand and slow the introduction of new aircraft. Assumptions relating to the sensitivity of aviation demand to price changes, and the degree to which higher fuel prices stimulate advances in the fuel efficiency of new aircraft play an important role in this result. Abstract and PDF report are also available on the MIT Joint Program on the Science and Policy of Global Change website (http://globalchange.mit.edu/).

The Prospects for Coal-To-Liquid Conversion: A General Equilibrium Analysis

2011-05-01T00:00:00Z

The Prospects for Coal-To-Liquid Conversion: A General Equilibrium Analysis Chen, Y.-H. Henry; Reilly, John M.; Paltsev, Sergey We investigate the economics of coal-to-liquid (CTL) conversion, a polygeneration technology that produces liquid fuels, chemicals, and electricity by coal gasification and Fischer-Tropsch process. CTL is more expensive than extant technologies when producing the same bundle of output. In addition, the significant carbon footprint of CTL may raise environmental concerns. However, as petroleum prices rise, this technology becomes more attractive especially in coal-abundant countries such as the U.S. and China. Furthermore, including a carbon capture and storage (CCS) option could greatly reduce its CO2 emissions at an added cost. To assess the prospects for CTL, we incorporate the engineering data for CTL from the U.S. Department of Energy (DOE) into the MIT Emissions Prediction and Policy Analysis (EPPA) model, a computable general equilibrium model of the global economy. Based on DOE's plant design that focuses mainly on liquid fuels production, we find that without climate policy, CTL has the potential to account for up to a third of the global liquid fuels supply by 2050 and at that level would supply about 4.6% of global electricity demand. A tight global climate policy, on the other hand, severely limits the potential role of the CTL even with the CCS option, especially if low-carbon biofuels are available. Under such a policy, world demand for petroleum products is greatly reduced, depletion of conventional petroleum is slowed, and so the price increase in crude oil is less, making CTL much less competitive. Abstract and PDF report are also available on the MIT Joint Program on the Science and Policy of Global Change website (http://globalchange.mit.edu/).

Health Damages from Air Pollution in China

2011-03-01T00:00:00Z

Health Damages from Air Pollution in China Matus, Kira; Nam, Kyung-Min; Selin, Noelle E.; Lamsal, Lok N.; Reilly, John M.; Paltsev, Sergey In China, elevated levels of urban air pollution result in substantial adverse health impacts for its large and rapidly growing urban population. An expanded version of the Emissions Prediction and Policy Analysis (EPPA), EPPA Health Effects, was used to evaluate air pollution-related health impacts on the Chinese economy. The effects of particulate matter and ozone were evaluated for 1975 to 2005, based on a set of epidemiological estimates of the effects of exposure to these pollutants. The estimated marginal welfare impact to the Chinese economy of air pollution levels above background levels increased from $22 billion in 1975 to $112 billion in 2005 (1997 US$), despite improvements in overall air quality. This increase is a result of the growing urban population and rising wages that thus increased the value of lost labor and leisure. Welfare losses from air pollution-related economic damage decreased from 14% of the historical welfare level in 1975 to 5% in 2005 because the total size of the economy grew much more rapidly than the absolute air pollution damages. Abstract and PDF report are also available on the MIT Joint Program on the Science and Policy of Global Change website (http://globalchange.mit.edu/).

Health Damages from Air Pollution in China

2011-03-01T00:00:00Z

A Method for Calculating Reference Evapotranspiration on Daily Time Scales

2011-02-01T00:00:00Z

A Method for Calculating Reference Evapotranspiration on Daily Time Scales Farmer, William; Strzepek, Ken; Schlosser, C. Adam; Droogers, Peter; Gao, Xiang Measures of reference evapotranspiration are essential for applications of agricultural management and water resources engineering. Using numerous esoteric variables, one can calculate daily reference evapotranspiration using the Modified Penman-Monteith methods. In 1985, Hargreaves developed a simplified method for estimating reference evapotranspiration. Similarly, Droogers and Allen improved upon Hargreaves’ method in 2002. Both methods provide excellent estimates of average daily rates for a given month, based on monthly climatology. The Hargraeves method also estimates daily rates based on daily data, though the Modified Hargreaves approach developed by Droogers and Allen is largely accepted as a stronger metric. Here efforts are made to improve the functionality of Droogers and Allen’s approach and to adapt it to provide daily estimates of reference evapotranspiration based on daily weather. The Hargreaves and Modified Hargeaves are used to calculate daily reference evapotranspiration based on daily data. The coefficients in these equations are then optimized to reduce the root mean squared difference between each estimate and the baseline value calculated by the Modified Penman-Monteith approach. The adapted method for daily reference evapotranspiration proves promising; estimating rates near a root mean squared difference of 1.07 mm/day. These results are validated with data from 1976-1980; here the root mean squared difference is 1.06 mm/day. Results are evaluated spatially and temporally. Weaknesses are seen in the estimates around clearly-defined summers. Further weaknesses are seen in pole-ward regions. Still, at the 1% significance level, the daily optimization of the Modified Hargreaves equation is found to be the best replica of the Modified Penman-Monteith method, globally. Finally, specific caveats and further avenues of research are noted. Overall, the daily Modified-Hargreaves method is advocated for general use in global studies where daily data and variation is of the utmost concern. Abstract and PDF report are also available on the MIT Joint Program on the Science and Policy of Global Change website (http://globalchange.mit.edu/)

General Equilibrium, Electricity Generation Technologies and the Cost of Carbon Abatement

2011-02-01T00:00:00Z

General Equilibrium, Electricity Generation Technologies and the Cost of Carbon Abatement Lanz, Bruno, 1980-; Rausch, Sebastian Electricity generation is a major contributor to carbon dioxide emissions, and a key determinant of abatement costs. Ex-ante assessments of carbon policies mainly rely on either of two modeling paradigms: (i) partial equilibrium models of the electricity sector that use bottom-up engineering data on generation technology costs, and (ii) multi-sector general equilibrium models that represent economic activities with smooth top-down aggregate production functions. In this paper, we examine the structural assumptions of these numerical techniques using a suite of models sharing common technological features and calibrated to the same benchmark data. First, our analysis provides evidence that general equilibrium effects of an economy-wide carbon policy are of first-order importance to assess abatement potentials and price changes in the electricity sector, suggesting that the parametrization of Marshallian demand in a partial equilibrium setting is problematic. Second, we find that top-down technology representations produce fuel substitution patterns that are inconsistent with bottom-up cost data, mainly because of difficulties in capturing the temporal and discrete nature of electricity generation by means of aggregate substitution elasticities. Our analysis highlights the difficulty to parameterize numerical models used for policy projections, and suggests that the integration of a bottom-up electricity sector model into a general equilibrium framework provides an attractive structural alternative for ex-ante policy modeling. Abstract and PDF report are also available on the MIT Joint Program on the Science and Policy of Global Change website (http://globalchange.mit.edu/)

What to Expect from Sectoral Trading: A U.S.–China Example

2011-02-01T00:00:00Z

What to Expect from Sectoral Trading: A U.S.–China Example Gavard, Claire; Winchester, Niven; Jacoby, Henry D.; Paltsev, Sergey In recent United Nations Framework Convention on Climate Change (UNFCCC) negotiations, sectoral mechanisms were proposed as a way to encourage early action and spur investment in low carbon technologies in developing countries, particularly in the electricity sector. Sectoral trading, which is one such proposition, involves including a sector from one or more nations in an international cap-and-trade system. In order to assess potential impacts from such a mechanism, we analyze trade in carbon permits between the Chinese electricity sector and a U.S. economy-wide cap-and-trade program using the MIT Emissions Prediction and Policy Analysis (EPPA) model. We find that this sectoral policy induces significant financial transfers between the two countries. In 2030, the U.S. purchases permits valued at $42 billion from China, which represents more than 46% of its capped emissions. Despite these transfers, there is only a small change in Chinese welfare. In the U.S., the availability of relatively cheap emissions permits significantly reduces the cost of climate policy. In China, sectoral trading increases the price of electricity and reduces the amount of electricity generated, particularly from coal, while opposite effects are observed in the U.S. Despite increases in the price of electricity in China, only small increases in electricity generation from nuclear and renewables are projected in the timeframe of our analysis (2010- 2030). Because the price of coal decree ses, we also find that sectoral trading leads to emissions increases in non-electricity sectors in China, a form of internal carbon leakage. Abstract and PDF report are also available on the MIT Joint Program on the Science and Policy of Global Change website (http://globalchange.mit.edu/)

The Impact of Border Carbon Adjustments under Alternative Producer Responses

2011-02-01T00:00:00Z

The Impact of Border Carbon Adjustments under Alternative Producer Responses Winchester, Niven Border carbon adjustments (BCAs) have been proposed to address leakage and competitiveness concerns. In traditional assessments, firms regard BCAs as output taxes rather than implicit emissions taxes. Using a stylized energy-economic model, we analyze the impact of BCAs for alternative producer responses. When firms view BCAs as an implicit emissions tax, the outcome depends on whether or not firms can differentiate production across destination markets. If firms are able to produce a low-emissions variety for regions imposing BCAs, results are similar to when firms regard BCAs as an output tax. If firms produce a single variety for all markets, BCAs result in larger leakage reductions than in standard approaches. We also find that BCAs are less effective at addressing competitive concerns in scenarios that result in larger leakage reductions. Abstract and PDF report are also available on the MIT Joint Program on the Science and Policy of Global Change website (http://globalchange.mit.edu/)

Climatology and Trends in the Forcing of the Stratospheric Ozone Transport

2011-01-01T00:00:00Z

Climatology and Trends in the Forcing of the Stratospheric Ozone Transport Monier, Erwan; Weare, Bryan C. A thorough analysis of the ozone transport was carried out using the Transformed-Mean Eulerian (TEM) tracer transport equation and the European Centre for Medium-Range Weather Forecasts (ECMWF) Re- Analysis (ERA-40). In this budget analysis, the chemical net production term, which is calculated as the residual of the other terms, displays the correct features of a chemical sink and source term, including location and seasonality, and shows a good agreement in magnitude compared to other methods of calculating ozone loss rates. This study provides further insight into the role of the eddy ozone transport and underlines its fundamental role in the recovery of the ozone hole during spring. The trend analysis reveals that the ozone hole intensification over 1980-2001 time period is not directly related to the trend in chemical losses, but more specifically to the balance in the trends in chemical losses and transport. That is because, in the SH from October to December, the large increase in the chemical destruction of ozone is balanced by an equally large trend in the eddy transport, associated with a small increase of the mean transport. This study shows that the increase in the eddy transport is characterized by more poleward ozone eddy flux by transient waves in the midlatitudes and by stationary waves in the polar region. This is primarily due to the presence of storm tracks in the midlatitudes and of the asymmetric Antarctic topography and ice-sea heating contrasts near the pole. Overall, this study makes clear of the fact that without an increase in the eddy ozone transport over the 1980-2001 time period, the ozone hole over Antarctica would be drastically more severe. This underlines the need for careful diagnostics of the eddy ozone transport in modeling studies of long-term changes in stratospheric ozone. Abstract and PDF report are also available on the MIT Joint Program on the Science and Policy of Global Change website (http://globalchange.mit.edu/)

Climatology and Trends in the Forcing of the Stratospheric Zonal-Mean Flow

2011-01-01T00:00:00Z

Climatology and Trends in the Forcing of the Stratospheric Zonal-Mean Flow Monier, Erwan; Weare, Bryan C. The momentum budget of the Transformed Eulerian-Mean (TEM) equation is calculated using the European Centre for Medium-Range Weather Forecasts (ECMWF) Re-Analysis (ERA-40). This study outlines the considerable contribution of the dissipative forcing, identified as a gravity wave drag, to the forcing of the zonal-mean flow. A trend analysis shows that, in recent times, the onset and break down of the Northern Hemisphere (NH) stratospheric polar night jet occur later. This temporal shift is associated with long-term changes in the planetary wave activity that are mainly due to synoptic waves. In the Southern Hemisphere (SH), the polar vortex shows a tendency to persist further into the SH summertime. This is explained by a statistically significant decrease in the intensity of the stationary EP flux divergence over the 1980-2001 period. The prevailing theory explaining the long-term changes in the stratospheric polar vortex postulates that ozone depletion leads to a strengthening of westerly winds which in turn causes the reduction in wave activity in high latitudes. We show that the strongest component in the dynamical response to stratospheric ozone changes is in fact the feedback of planetary wave activity on the zonal wind. Finally, we identify long-term changes in the Brewer-Dobson circulation that are mainly caused by trends in the planetary wave activity during winter and by trends in the gravity wave body force otherwise. Abstract and PDF report are also available on the MIT Joint Program on the Science and Policy of Global Change website (http://globalchange.mit.edu/)

Modeling the Global Water Resource System in an Integrated Assessment Modeling Framework: IGSM-WRS

2010-09-01T00:00:00Z

Modeling the Global Water Resource System in an Integrated Assessment Modeling Framework: IGSM-WRS Strzepek, Kenneth M.; Schlosser, C. Adam; Farmer, William; Awadalla, Sirein; Baker, Jonathan; Rosegrant, Mark; Gao, Xiang The availability of water resources affects energy, agricultural and environmental systems, which are linked together as well as to climate via the water cycle. As such, watersheds and river basins are directly impacted by local and regional climate variations and change. In turn, these managed systems provide direct inputs to the global economy that serve and promote public health, agricultural and energy production, ecosystem surfaces and infrastructure. We have enhanced the Integrated Global System Model (IGSM) framework capabilities to model effects on the managed water-resource systems of the influence of potential climate change and associated shifts in hydrologic variation and extremes (i.e. non-stationarity in the hydro-climate system), and how we may be able to adapt to these impacts. A key component of this enhancement is the linkage of the Water Resources System (WRS) into the IGSM framework. WRS is a global river basin scale model of water resources management, agricultural (rain-fed and irrigated crops and livestock) and aquatic environmental systems. In particular, WRS will provide the capability within the IGSM framework to explore allocation of water among irrigation, hydropower, urban/industrial, and in-stream uses and investigate how society might adapt water resources due to shifts in hydro-climate variations and extremes. This paper presents the overall design of WRS, its linkages to the land system and economic models of the IGSM, and results of test bed runs of WRS components to address issues of temporal and spatial scales in these linkages. Abstract and PDF report are also available on the MIT Joint Program on the Science and Policy of Global Change website (http://globalchange.mit.edu/)

On the Correlation between Forcing and Climate Sensitivity

2010-08-01T00:00:00Z

On the Correlation between Forcing and Climate Sensitivity Sokolov, Andrei The possible correlation between climate sensitivity and radiative forcing is studied using versions of the NCAR Community Atmospheric Model (CAM) model with different climate sensitivities. No such correlation was found for the CO2 forcing. A weak correlation for the direct sulfate aerosol forcing is associated with differences in cloud cover in control climate simulations with different versions of the model. Presented results suggest that correlation between sensitivity and radiative forcing in the 20th century simulations with different AOGCMs is not a reflection of physical reality but is a result of different treatments of forcing agents, primarily aerosols. Abstract and PDF report are also available on the MIT Joint Program on the Science and Policy of Global Change website (http://globalchange.mit.edu/)

Combining a Renewable Portfolio Standard with a Cap-and-Trade Policy: A General Equilibrium Analysis

2010-07-01T00:00:00Z

Combining a Renewable Portfolio Standard with a Cap-and-Trade Policy: A General Equilibrium Analysis Morris, Jennifer; Reilly, John M.; Paltsev, Sergey Many efforts to address greenhouse gas emissions combine a cap-and-trade system with other measures such as a renewable portfolio standard. In this paper we use a computable general equilibrium (CGE) model, the MIT Emissions Prediction and Policy Analysis (EPPA) model, to investigate the effects of combining these policies. We find that adding an RPS requiring 20 percent renewables by 2020 to a cap that reduces emissions by 80% below 1990 levels by 2050 increases the net present value welfare cost of meeting such a cap by 25 percent over the life of the policy, while reducing the CO2-equivalent price by about 20 percent each year. Abstract and PDF report are also available on the MIT Joint Program on the Science and Policy of Global Change website (http://globalchange.mit.edu/)

The Future of U.S. Natural Gas Production, Use, and Trade

2010-06-01T00:00:00Z

The Future of U.S. Natural Gas Production, Use, and Trade Paltsev, Sergey; Jacoby, Henry D.; Reilly, John M.; Ejaz, Q.J.; O’Sullivan, F.; Morris, Jennifer; Rausch, Sebastian; Winchester, Niven; Kragha, O. Two computable general equilibrium models, one global and the other providing U.S. regional detail, are applied to analysis of the future of U.S. natural gas as an input to an MIT study of the topic. The focus is on uncertainties including the scale and cost of gas resources, the costs of competing technologies, the pattern of greenhouse gas mitigation, and the evolution of global natural gas markets. Results show that the outlook for gas over the next several decades is very favorable. In electric generation, given the unproven and relatively high cost of other low-carbon generation alternatives, gas likely is the preferred alternative to coal. A broad GHG pricing policy would increase gas use in generation but reduce use in other sectors, on a balance increasing its role from present levels. The shale gas resource is a major contributor to this optimistic view of the future of gas, but it is far from a panacea over the longer term. Gas can be an effective bridge to a lower emissions future, but investment in the development of still lower CO2 technologies remains an important priority. Also, international gas resources may well prove to be less costly than those in the U.S., except for the lowest-cost domestic shale resources, and the emergence of an integrated global gas market could result in significant U.S. gas imports. Abstract and PDF report are also available on the MIT Joint Program on the Science and Policy of Global Change website (http://globalchange.mit.edu/)

Distributional Implications of Alternative U.S. Greenhouse Gas Control Measures

2010-06-01T00:00:00Z

Distributional Implications of Alternative U.S. Greenhouse Gas Control Measures Rausch, Sebastian; Metcalf, Gilbert E.; Reilly, John M.; Paltsev, Sergey We analyze the distributional and efficiency impacts of different allowance allocation schemes for a national cap and trade system using the USREP model, a new recursive dynamic computable general equilibrium model of the U.S. economy. The USREP model tracks nine different income groups and twelve different geographic regions within the United States. Recently proposed legislation include the Waxman-Markey House bill, the similar Kerry-Boxer bill in the Senate that has been replaced by a Kerry-Lieberman draft bill, and the Cantwell-Collins Senate bill that takes a different approach to revenue allocation. We consider allocation schemes motivated by these recent proposals applied to a comprehensive national cap and trade system that limits cumulative greenhouse gas emissions over the control period to 203 billion metric tons. The policy target approximates national goals identified in pending legislation. We find that the allocation schemes in all proposals are progressive over the lower half of the income distribution and proportional in the upper half of the income distribution. Scenarios based on the Cantwell-Collins allocation proposal are less progressive in early years and have lower welfare costs due to smaller redistribution to low income households and consequently lower income-induced increases in energy demand and less savings and investment. Scenarios based on the three other allocation schemes tend to overcompensate some adversely affected income groups and regions in early years but this dissipates over time as the allowance allocation effect becomes weaker. Finally we find that carbon pricing by itself (ignoring the return of carbon revenues through allowance allocations) is proportional to modestly progressive. This striking result follows from the dominance of the sources over uses side impacts of the policy and stands in sharp contrast to previous work that has focused only on the uses side. The main reason is that lower income households derive a large fraction of income from government transfers and, reflecting the reality that these are generally indexed to inflation, we hold the transfers constant in real terms. As a result this source of income is unaffected by carbon pricing, while wage and capital income is affected. Abstract and PDF report are also available on the MIT Joint Program on the Science and Policy of Global Change website (http://globalchange.mit.edu/)

Canada’s Bitumen Industry Under CO2 Constraints

2010-01-01T00:00:00Z

Canada’s Bitumen Industry Under CO2 Constraints Chen, Y.-H. Henry; Paltsev, Sergey; Reilly, John; Chan, Gabriel We investigate the effects of implementing CO2 emissions reduction policies on Canada’s oil sands industry, the largest of its kind in the world. The production of petroleum products from oils sands involves extraction of bitumen from the oil sands, upgrading it to a synthetic crude oil by adding lighter hydrocarbons, and then use of more conventional petroleum refining processes to create products such as gasoline and diesel. The relatively heavy crude generally requires the use of cracking and other advanced refinery operations to generate a product slate with substantial fractions of the higher value petroleum products such as diesel and gasoline. Each part of the process involves significant amounts of energy, and that contributes to a high level of CO2 emissions. We apply the MIT Emissions Prediction and Policy Analysis (EPPA) model, a computable general equilibrium model of the world economy, augmented to include detail on the oil sands production processes, including the possibility of carbon capture and storage (CCS). We find: (1) without climate policy annual Canadian bitumen production increases over 6-fold from 2005 to 2050; (2) with CO2 emissions caps implemented in developed countries, Canadian bitumen production drops by nearly 65% from the reference 6-fold increase and bitumen upgrading capacity moves to the developing countries; (3) with CO2 emissions caps implemented worldwide, the Canadian bitumen production becomes essentially non-viable even with CCS technology, at least through our 2050 horizon. The main reason for the demise of the oil sands industry with global CO2 policy is that the demand for oil worldwide drops substantially. CCS takes care of emissions from the oil sands production, upgrading, and refining processes, at a cost, but there is so little demand for petroleum products which still emit CO2 when used that it can be met with conventional oil resources that entail less CO2 emissions in the production process. Abstract and PDF report are also available on the MIT Joint Program on the Science and Policy of Global Change website (http://globalchange.mit.edu/).

Will Border Carbon Adjustments Work?

2010-02-01T00:00:00Z

Will Border Carbon Adjustments Work? Reilly, John; Paltsev, Sergey; Winchester, Niven The potential for greenhouse gas (GHG) restrictions in some nations to drive emission increases in other nations, or leakage, is a contentious issue in climate change negotiations. We evaluate the potential for border carbon adjustments (BCAs) to address leakage concerns using an economy-wide model. For 2025, we find that BCAs reduce leakage by up to two-thirds, but result in only modest reductions in global emissions and significantly reduce welfare. In contrast, BCA-equivalent leakage reductions can be achieved by very small emission charges or efficiency improvements in nations targeted by BCAs, which have negligible welfare effects. We conclude that BCAs are a costly method to reduce leakage but such policies may be effective coercion strategies. We also investigate the impact of BCAs on sectoral output and evaluate the leakage contributions of trade and changes in the price of crude oil. Abstract and PDF report are also available on the MIT Joint Program on the Science and Policy of Global Change website (http://globalchange.mit.edu/).

Distributional Impacts of a U.S. Greenhouse Gas Policy: A General Equilibrium Analysis of Carbon Pricing

2009-11-01T00:00:00Z

Distributional Impacts of a U.S. Greenhouse Gas Policy: A General Equilibrium Analysis of Carbon Pricing Paltsev, Sergey; Reilly, John M.; Metcalf, Gilbert E.; Rausch, Sebastian We develop a new model of the U.S., the U.S. Regional Energy Policy (USREP) model that is resolved for large states and regions of the U.S. and by income class and apply the model to investigate a $15 per ton CO2 equivalent price on greenhouse gas emissions. Previous estimates of distributional impacts of carbon pricing have been done outside of the model simulation and have been based on energy expenditure patterns of households in different regions and of different income levels. By estimating distributional effects within the economic model, we include the effects of changes in capital returns and wages on distribution and find that the effects are significant and work against the expenditure effects. We find the following: First, while results based only on energy expenditure have shown carbon pricing to be regressive we find the full distributional effect to be neutral or slightly progressive. This demonstrates the importance of tracing through all economic impacts and not just focusing on spending side impacts. Second, the ultimate impact of such a policy on households depends on how allowances, or the revenue raised from auctioning them, is used. Free distribution to firms would be highly regressive, benefiting higher income households and forcing lower income households to bear the full cost of the policy and what amounts to a transfer of wealth to higher income households. Lump sum distribution through equal-sized household rebates would make lower income households absolutely better off while shifting the costs to higher income households. Schemes that would cut taxes are generally slightly regressive but improve somewhat the overall efficiency of the program. Third, proposed legislation would distribute allowances to local distribution companies (electricity and natural gas distributors) and public utility commissions would then determine how the value of those allowances was used. A significant risk in such a plan is that distribution to households might be perceived as lowering utility rates That reduced the efficiency of the policy we examined by 40 percent. Finally, the states on the coasts bear little cost or can benefit because of the distribution of allowance revenue while mid-America and southern states bear the highest costs. This regional pattern reflects energy consumption and energy production difference among states. Use of allowance revenue to cut taxes generally exacerbates these regional differences because coastal states are also generally higher income states, and those with higher incomes benefit more from tax cuts. Abstract and PDF report are also available on the MIT Joint Program on the Science and Policy of Global Change website (http://globalchange.mit.edu/).

Development of a Fast and Detailed Model of Urban-Scale Chemical and Physical Processing

2009-10-01T00:00:00Z

Development of a Fast and Detailed Model of Urban-Scale Chemical and Physical Processing Prinn, Ronald G.; Cohen, Jason B. A reduced form metamodel has been produced to simulate the effects of physical, chemical, and meteorological processing of highly reactive trace species in hypothetical urban areas, which is capable of efficiently simulating the urban concentration, surface deposition, and net mass flux of these species. A polynomial chaos expansion and the probabilistic collocation method have been used for the metamodel, and its coefficients were fit so as to be applicable under a broad range of present-day and future conditions. The inputs upon which this metamodel have been formed are based on a combination of physical properties (average temperature, diurnal temperature range, date, and latitude), anthropogenic properties (patterns and amounts of emissions), and the surrounding environment (background concentrations of certain species). Probability Distribution Functions (PDFs) of the inputs were used to run a detailed parent chemical and physical model, the Comprehensive Air Quality Model with Extensions (CAMx), thousands of times. Outputs from these runs were used in turn to both determine the coefficients of and test the precision of the metamodel, as compared with the detailed parent model. The deviations between the metamodel and the parent mode for many important species (O3, CO, NOx, and BC) were found to have a weighted RMS error less than 10% in all cases, with many of the specific cases having a weighted RMS error less than 1%. Some of the other important species (VOCs, PAN, OC, and sulfate aerosol) usually have their weighted RMS error less than 10% as well, except for a small number of cases. These cases, in which the highly non-linear nature of the processing is too large for the third order metamodel to give an accurate fit, are explained in terms of the complexity and non-linearity of the physical, chemical, and meteorological processing. In addition, for those species in which good fits have not been obtained, the program has been designed in such a way that values which are not physically realistic are flagged. Sensitivity tests have been performed, to observe the response of the 16 metamodels (4 different meteorologies and 4 different urban types) to a broad set of potential inputs. These results were compared with observations of ozone, CO, formaldehyde, BC, and PM10 from a few well observed urban areas, and in most of the cases, the output distributions were found to be within ranges of the observations. Overall, a set of efficient and robust metamodels have been generated which are capable of simulating the effects of various physical, chemical, and meteorological processing, and capable of determining the urban concentrations, mole fractions, and fluxes of species, important to human health and the climate. Abstract and PDF report are also available on the MIT Joint Program on the Science and Policy of Global Change website (http://globalchange.mit.edu/).

Analysis of Climate Policy Targets under Uncertainty

2009-09-01T00:00:00Z

Analysis of Climate Policy Targets under Uncertainty Jacoby, Henry D.; Prinn, Ronald G.; Melillo, Jerry M.; Sarofim, Marcus C.; Kicklighter, David W.; Wang, Chien; Schlosser, C. Adam; Paltsev, Sergey; Forest, Chris Eliot; Reilly, John M.; Sokolov, Andrei P.; Webster, Mort D. Although policymaking in response to the climate change is essentially a challenge of risk management, most studies of the relation of emissions targets to desired climate outcomes are either deterministic or subject to a limited representation of the underlying uncertainties. Monte Carlo simulation, applied to the MIT Integrated Global System Model (an integrated economic and earth system model of intermediate complexity), is used to analyze the uncertain outcomes that flow from a set of century-scale emissions targets developed originally for a study by the U.S. Climate Change Science Program. Results are shown for atmospheric concentrations, radiative forcing, sea ice cover and temperature change, along with estimates of the odds of achieving particular target levels, and for the global costs of the associated mitigation policy. Comparison with other studies of climate targets are presented as evidence of the value, in understanding the climate challenge, of more complete analysis of uncertainties in human emissions and climate system response. Abstract and PDF report are also available on the MIT Joint Program on the Science and Policy of Global Change website (http://globalchange.mit.edu/).

Assessing Evapotranspiration Estimates from the Global Soil Wetness Project Phase 2 (GSWP-2) Simulations

2009-09-01T00:00:00Z

Assessing Evapotranspiration Estimates from the Global Soil Wetness Project Phase 2 (GSWP-2) Simulations Gao, Xiang; Schlosser, C. Adam We assess the simulations of global-scale evapotranspiration from the Global Soil Wetness Project Phase 2 (GSWP-2) within a global water-budget framework. The scatter in the GSWP-2 global evapotranspiration estimates from various land surface models can constrain the global, annual water budget fluxes to within ±2.5%, and by using estimates of global precipitation, the residual ocean evaporation estimate falls within the range of other independently derived bulk estimates. However, the GSWP-2 scatter cannot entirely explain the imbalance of the annual fluxes from a modern-era, observationally-based global water budget assessment, and inconsistencies in the magnitude and timing of seasonal variations between the global water budget terms are found. Inter-model inconsistencies in evapotranspiration are largest for high latitude inter-annual variability as well as for inter-seasonal variations in the tropics, and analyses with field-scale data also highlights model disparity at estimating evapotranspiration in high latitude regions. Analyses of the sensitivity simulations that replace uncertain forcings (i.e. radiation, precipitation, and meteorological variables) indicate that global (land) evapotranspiration is slightly more sensitive to precipitation than net radiation perturbations, and the majority of the GSWP-2 models, at a global scale, fall in a marginally moisture-limited evaporative condition. Finally, the range of global evapotranspiration estimates among the models is larger than any bias caused by uncertainties in the GSWP-2 atmospheric forcing, indicating that model structure plays a more important role toward improving global land evaporation estimates (as opposed to improved atmospheric forcing). Abstract and PDF report are also available on the MIT Joint Program on the Science and Policy of Global Change website (http://globalchange.mit.edu/).

Measuring Welfare Loss Caused by Air Pollution in Europe: A CGE Analysis

2009-08-01T00:00:00Z

Measuring Welfare Loss Caused by Air Pollution in Europe: A CGE Analysis Paltsev, Sergey; Reilly, John M.; Selin, Noelle E.; Nam, Kyung-Min To evaluate the socio-economic impacts of air pollution, we develop an integrated approach based on computable general equilibrium (CGE). Applying our approach to Europe shows that even there, where air quality is relatively high compared with other parts of the world, health-related damages caused by air pollution are substantial. We estimate that in 2005, air pollution in Europe caused a consumption loss of around 220 billion Euro (year 2000 prices, around 3 percent of consumption level) and a social welfare loss of around 370 billion Euro, measured as the sum of lost consumption and leisure (around 2 percent of welfare level). In addition, we estimated that a set of 2020-targeting air quality improvement policy scenarios, which are proposed in the 2005 CAFE program, would bring 18 European countries as a whole a welfare gain of 37 to 49 billion Euro (year 2000 prices) in year 2020 alone. Abstract and PDF report are also available on the MIT Joint Program on the Science and Policy of Global Change website (http://globalchange.mit.edu/).

Global Health and Economic Impacts of Future Ozone Pollution

2009-08-01T00:00:00Z

Global Health and Economic Impacts of Future Ozone Pollution Webster, Mort D.; Prinn, Ronald G.; Paltsev, Sergey; Reilly, John M.; Nam, Kyung-Min; Wu, Shiliang; Selin, Noelle E. We assess the human health and economic impacts of projected 2000-2050 changes in ozone pollution using the MIT Emissions Prediction and Policy Analysis-Health Effects (EPPA-HE) model, in combination with results from the GEOS-Chem global tropospheric chemistry model that simulated climate and chemistry effects of IPCC SRES emissions. We use EPPA to assess the human health damages (including acute mortality and morbidity outcomes) caused by ozone pollution and quantify their economic impacts in sixteen world regions. We compare the costs of ozone pollution under scenarios with 2000 and 2050 ozone precursor and greenhouse gas emissions (SRES A1B scenario). We estimate that health costs due to global ozone pollution above pre-industrial levels by 2050 will be $580 billion (year 2000$) and that acute mortalities will exceed 2 million. We find that previous methodologies underestimate costs of air pollution by more than a third because they do not take into account the long-term, compounding effects of health costs. The economic effects of emissions changes far exceed the influence of climate alone. Abstract and PDF report are also available on the MIT Joint Program on the Science and Policy of Global Change website (http://globalchange.mit.edu/).

Biofuels, Climate Policy and the European Vehicle Fleet

2009-08-01T00:00:00Z

Biofuels, Climate Policy and the European Vehicle Fleet Rausch, Sebastian; Reilly, John M.; Paltsev, Sergey; Gitiaux, Xavier We examine the effect of biofuels mandates and climate policy on the European vehicle fleet, considering the prospects for diesel and gasoline vehicles. We use the MIT Emissions Prediction and Policy Analysis (EPPA) model, which is a general equilibrium model of the world economy. We expand this model by explicitly introducing current generation biofuels, by accounting for stock turnover of the vehicle fleets and by disaggregating gasoline and diesel cars. We find that biofuels mandates alone do not substantially change the share of diesel cars in the total fleet given the current structure of fuel taxes and tariffs in Europe that favors diesel vehicles. Jointly implemented changes in fiscal policy, however, can reverse the trend toward more diesel vehicles. We find that harmonizing fuel taxes reduces the welfare cost associated with renewable fuel policy and lowers the share of diesel vehicles in the total fleet to 21% by 2030 compared to 25% in 2010. We also find that eliminating tariffs on biofuel imports, which under the existing regime favor biodiesel and impede sugar ethanol imports, is welfare-enhancing and brings about further substantial reductions in CO2 emissions. Abstract and PDF report are also available on the MIT Joint Program on the Science and Policy of Global Change website (http://globalchange.mit.edu/).

Potential Climatic Impacts and Reliability of Very Large-Scale Wind Farms

2009-06-01T00:00:00Z

Potential Climatic Impacts and Reliability of Very Large-Scale Wind Farms Prinn, Ronald G.; Wang, Chien Meeting future world energy needs while addressing climate change requires large-scale deployment of low or zero greenhouse gas (GHG) emission technologies such as wind energy. The widespread availability of wind power has fueled legitimate interest in this renewable energy source as one of the needed technologies. For very large-scale utilization of this resource, there are however potential environmental impacts, and also problems arising from its inherent intermittency, in addition to the present need to lower unit costs. To explore some of these issues, we use a threedimensional climate model to simulate the potential climate effects associated with installation of wind-powered generators over vast areas of land or coastal ocean. Using windmills to meet 10% or more of global energy demand in 2100, could cause surface warming exceeding 1oC over land installations. In contrast, surface cooling exceeding 1oC is computed over ocean installations, but the validity of simulating the impacts of windmills by simply increasing the ocean surface drag needs further study. Significant warming or cooling remote from both the land and ocean installations, and alterations of the global distributions of rainfall and clouds also occur. These results are influenced by the competing effects of increases in roughness and decreases in wind speed on near-surface turbulent heat fluxes, the differing nature of land and ocean surface friction, and the dimensions of the installations parallel and perpendicular to the prevailing winds. These results are also dependent on the accuracy of the model used, and the realism of the methods applied to simulate windmills. Additional theory and new field observations will be required for their ultimate validation. Intermittency of wind power on daily, monthly and longer time scales as computed in these simulations and inferred from meteorological observations, poses a demand for one or more options to ensure reliability, including backup generation capacity, very long distance power transmission lines, and onsite energy storage, each with specific economic and/or technological challenges. Abstract and PDF report are also available on the MIT Joint Program on the Science and Policy of Global Change website (http://globalchange.mit.edu/).

A semi-empirical representation of the temporal variation of total greenhouse gas levels expressed as equivalent levels of carbon dioxide

2009-06-01T00:00:00Z

A semi-empirical representation of the temporal variation of total greenhouse gas levels expressed as equivalent levels of carbon dioxide Cunnold, Derek; Prinn, Ronald G.; Huang, Jin; Wang, Ray In order to examine the underlying longer-term trends in greenhouse gases, that are driven for example by anthropogenic emissions or climate change, it is useful to remove the recurring effects of natural cycles and oscillations on the sources and/or sinks of those gases that have strong biological (e.g., CO2, CH4, N2O) and/or photochemical (e.g. CH4) influences on their global atmospheric cycles. We use global observations to calculate monthly estimates of greenhouse gas levels expressed as CO2 equivalents, and then fit these estimates to a semi-empirical model that includes the natural seasonal, QBO, and ENSO variations, as well as a second order polynomial expressing longer-term variations. We find that this model provides a reasonably accurate fit to the observation-based monthly data. We also show that this semiempirical model has some predictive capability; that is it can be used to provide a reasonably reliable estimate of CO2 equivalents at the current time using validated observations that lag real time by a few to several months. Abstract and PDF report are also available on the MIT Joint Program on the Science and Policy of Global Change website (http://globalchange.mit.edu/).

The Cost of Climate Policy in the United States

2009-04-01T00:00:00Z

The Cost of Climate Policy in the United States Morris, Jennifer F.; Jacoby, Henry D.; Reilly, John M.; Paltsev, Sergey We consider the cost of meeting emissions reduction targets consistent with a G8 proposal of a 50 percent global reduction in emissions by 2050, and an Obama Administration proposal of an 80 percent reduction over this period. We apply the MIT Emissions Prediction and Policy Analysis (EPPA), modeling these two policy scenarios if met by applying a national cap-and-trade system, and compare results with an earlier EPPA analysis of reductions of this stringency. We also test results to alternative assumptions about program coverage, banking behavior, and cost of technology in the electric power sector. Two main messages emerge from the exercise. First, technology uncertainties have a huge effect on the generation mix but only a moderate effect on the emissions price and welfare cost of achieving the assumed targets. Measured in terms of changes in economic welfare, the economic cost of 80 percent reduction by 2050 is in the range of 2 to 3% by 2050, with CO2 prices between $48 and $67 in 2015 rising to between $190 and $266 by 2050. Second, implementation matters. When an idealized economy-wide cap-and-trade is replaced by coverage omitting some sectors, or if the credibility of long-term target is weak (limiting banking behavior) prices and welfare costs change substantially. Abstract and PDF report are also available on the MIT Joint Program on the Science and Policy of Global Change website (http://globalchange.mit.edu/).

Prospects for Plug-in Hybrid Electric Vehicles in the United States and Japan: A General Equilibrium Analysis

2009-04-01T00:00:00Z

Prospects for Plug-in Hybrid Electric Vehicles in the United States and Japan: A General Equilibrium Analysis Reilly, John M.; Paltsev, Sergey; Karplus, Valerie J. The plug-in hybrid electric vehicle (PHEV) may offer a potential near term, low carbon alternative to today's gasoline- and diesel-powered vehicles. A representative vehicle technology that runs on electricity in addition to conventional fuels was introduced into the MIT Emissions Prediction and Policy Analysis (EPPA) model as a perfect substitute for internal combustion engine (ICE-only) vehicles in two likely early-adopting markets, the United States and Japan. We investigate the effect of relative vehicle cost and all-electric range on the timing of PHEV market entry in the presence and absence of an advanced cellulosic biofuels technology and a strong (450ppm) economy-wide carbon constraint. Vehicle cost could be a significant barrier to PHEV entry unless fairly aggressive goals for reducing battery costs are met. If a low cost vehicle is available we find that the PHEV has the potential to reduce CO2 emissions, refined oil demand, and under a carbon policy the required CO2 price in both the United States and Japan. The emissions reduction potential of PHEV adoption depends on the carbon intensity of electric power generation and the size of the vehicle fleet. Thus, the technology is much more effective in reducing CO2 emissions if adoption occurs under an economy-wide cap and trade system that also encourages low-carbon electricity generation. Abstract and PDF report are also available on the MIT Joint Program on the Science and Policy of Global Change website (http://globalchange.mit.edu/)

The EU’s Emissions Trading Scheme: A Prototype Global System?

2009-02-01T00:00:00Z

The EU’s Emissions Trading Scheme: A Prototype Global System? Ellerman, A. Denny The European Union's Emission Trading Scheme (EU ETS) is the world's first multinational cap-and-trade system for greenhouse gases. As an agreement between sovereign nations with diverse historical, institutional, and economic circumstances, it can be seen as a prototype for an eventual global climate regime. Interestingly, the problems that are often seen as dooming a global trading system — international financial flows and institutional readiness — haven't appeared in the EU ETS, at least not yet. The more serious problems that emerge from the brief experience of the EU ETS are those of (1) developing a central coordinating organization, (2) devising side benefits to encourage participation, and (3) dealing with the interrelated issues of harmonization, differentiation, and stringency. The pre-existing organizational structure and membership benefits of the European Union provided convenient and almost accidental solutions to the need for a central institution and side benefits, but these solutions will not work on a global scale and there are no obvious substitutes. Furthermore, the EU ETS is only beginning to test the practicality of harmonizing allocations within the trading system, differentiating responsibilities among participants, and increasing the stringency of emissions caps. The trial period of the EU ETS punted on these problems, as was appropriate for a trial period, but they are now being addressed seriously. From a global perspective, the answers that are being worked out in Europe will say a great deal about what will be feasible on a broader, global scale. Abstract and PDF report are also available on the MIT Joint Program on the Science and Policy of Global Change website (http://globalchange.mit.edu/).

Designing a U.S. Market for CO2

2009-02-01T00:00:00Z

Designing a U.S. Market for CO2 Parsons, John E.; Ellerman, A. Denny; Feilhauer, Stephan M. (Stephan Marvin) In this paper we focus on one component of the cap-and-trade system: the markets that arise for trading allowances after they have been allocated or auctioned. The efficient functioning of the market is key to the success of cap-and-trade as a system. We review the performance of the EU CO2 market and the U.S. SO2 market and examine how the flexibility afforded by banking and borrowing, and the limitations on banking and borrowing, have impacted the evolution of price in both markets. While both markets have generally functioned well, certain episodes illustrate the importance of designing the rules to encourage liquidity in the market. Abstract and PDF report are also available on the MIT Joint Program on the Science and Policy of Global Change website (http://globalchange.mit.edu/).

Probabilistic Forecast for 21st Century Climate Based on Uncertainties in Emissions (without Policy) and Climate Parameters

2009-01-01T00:00:00Z

Probabilistic Forecast for 21st Century Climate Based on Uncertainties in Emissions (without Policy) and Climate Parameters Sokolov, Andrei P.; Stone, Peter H.; Forest, Chris Eliot; Prinn, Ronald G.; Sarofim, Marcus C.; Webster, Mort D.; Paltsev, Sergey; Schlosser, C. Adam.; Kicklighter, David W.; Dutkiewicz, Stephanie.; Reilly, John M.; Wang, Chien.; Felzer, Benjamin Seth.; Jacoby, Henry D. The MIT Integrated Global System Model is used to make probabilistic projections of climate change from 1861 to 2100. Since the model's first projections were published in 2003 substantial improvements have been made to the model and improved estimates of the probability distributions of uncertain input parameters have become available. The new projections are considerably warmer than the 2003 projections, e.g., the median surface warming in 2091 to 2100 is 5.1°C compared to 2.4°C in the earlier study. Many changes contribute to the stronger warming; among the more important ones are taking into account the cooling in the second half of the 20th century due to volcanic eruptions for input parameter estimation and a more sophisticated method for projecting GDP growth which eliminated many low emission scenarios. However, if recently published data, suggesting stronger 20th century ocean warming, are used to determine the input climate parameters, the median projected warning at the end of the 21st century is only 4.1°C. Nevertheless all our simulations have a very small probability of warming less than 2.4°C, the lower bound of the IPCC AR4 projected likely range for the A1FI scenario, which has forcing very similar to our median projection. The probability distribution for the surface warming produced by our analysis is more symmetric than the distribution assumed by the IPCC due to a different feedback between the climate and the carbon cycle, resulting from a different treatment of the carbon-nitrogen interaction in the terrestrial ecosystem. Abstract and PDF report are also available on the MIT Joint Program on the Science and Policy of Global Change website (http://globalchange.mit.edu/).

Unintended Environmental Consequences of a Global Biofuels Program

2009-01-01T00:00:00Z

Unintended Environmental Consequences of a Global Biofuels Program Melillo, Jerry M.; Gurgel, Angelo C.; Kicklighter, David W.; Reilly, John M.; Cronin, Timothy W.; Felzer, Benjamin Seth.; Paltsev, Sergey; Schlosser, C. Adam.; Sokolov, Andrei P.; Wang, Xiaodong Biofuels are being promoted as an important part of the global energy mix to meet the climate change challenge. The environmental costs of biofuels produced with current technologies at small scales have been studied, but little research has been done on the consequences of an aggressive global biofuels program with advanced technologies using cellulosic feedstocks. Here, with simulation modeling, we explore two scenarios for cellulosic biofuels production and find that both could contribute substantially to future global-scale energy needs, but with significant unintended environmental consequences. As the land supply is squeezed to make way for vast areas of biofuels crops, the global landscape is defined by either the clearing of large swathes of natural forest, or the intensification of agricultural operations worldwide. The greenhouse gas implications of land-use conversion differ substantially between the two scenarios, but in both, numerous biodiversity hotspots suffer from serious habitat loss. Cellulosic biofuels may yet serve as a crucial wedge in the solution to the climate change problem, but must be deployed with caution so as not to jeopardize biodiversity, compromise ecosystems services, or undermine climate policy. Abstract and PDF report are also available on the MIT Joint Program on the Science and Policy of Global Change website (http://globalchange.mit.edu/).

Sharing the Burden of GHG Reductions

2008-11-01T00:00:00Z

Sharing the Burden of GHG Reductions Jacoby, Henry D.; Babiker, Mustafa M.H.; Paltsev, Sergey; Reilly, John M. The G8 countries propose a goal of a 50% reduction in global emissions by 2050, in an effort that needs to take account of other agreements specifying that developing countries are to be provided with incentives to action and protected from the impact of measures taken by others. To help inform international negotiations of measures to achieve these goals we develop a technique for endogenously estimating the allowance allocations and associated financial transfers necessary to achieve predetermined distributional outcomes and apply it in the MIT Emissions Prediction and Policy Analysis (EPPA) model. Possible burden sharing agreements are represented by different allowance allocations (and resulting financial flows) in a global cap-and-trade system. Cases studied include agreements that allocate the burden based on simple allocation rules found in current national proposals and alternatives that specify national equity goals for both developing and developed countries. The analysis shows the ambitious nature of this reduction goal: universal participation will be necessary and the welfare costs can be both substantial and wildly different across regions depending on the allocation method chosen. The choice of allocation rule is shown to affect the magnitude of the task and required emissions price because of income effects. If developing countries are fully compensated for the costs of mitigation then the welfare costs to developed countries, if shared equally, are around 2% in 2020, rising to some 10% in 2050, and the implied financial transfers are large—over $400 billion per year in 2020 and rising to around $3 trillion in 2050. For success in dealing with the climate threat any negotiation of long-term goals and paths to achievement need to be grounded in a full understanding of the substantial amounts at stake. Abstract and PDF report are also available on the MIT Joint Program on the Science and Policy of Global Change website (http://globalchange.mit.edu/).

Sensitivity of Climate Change Projections to Uncertainties in the Estimates of Observed Changes in Deep-Ocean Heat Content

2008-11-01T00:00:00Z

Sensitivity of Climate Change Projections to Uncertainties in the Estimates of Observed Changes in Deep-Ocean Heat Content Sokolov, Andrei P.; Forest, Chris Eliot; Stone, Peter H. The MIT 2D climate model is used to make probabilistic projections for changes in global mean surface temperature and for thermosteric sea level rise under a variety of forcing scenarios. The uncertainties in climate sensitivity and rate of heat uptake by the deep ocean are quantified by using the probability distributions derived from observed 20th century temperature changes. The impact on climate change projections of using the smallest and largest estimates of 20th century deep ocean warming is explored. The impact is large in the case of global mean thermosteric sea level rise. In the MIT reference ("business as usual") scenario the median rise by 2100 is 27 and 43 cm in the respective cases. The impact on increases in global mean surface air temperature is more modest, 4.9 C and 3.9 C in the two respective cases, because of the correlation between climate sensitivity and ocean heat uptake required by 20th century surface and upper air temperature changes. The results are also compared with the projections made by the IPCC AR4's multi-model ensemble for several of the SRES scenarios. The multi-model projections are more consistent with the MIT projections based on the largest estimate of ocean warming. However the range for the rate of heat uptake by the ocean suggested by the lowest estimate of ocean warming is more consistent with the range suggested by the 20th century changes in surface and upper air temperatures, combined with expert prior for climate sensitivity. Abstract and PDF report are also available on the MIT Joint Program on the Science and Policy of Global Change website (http://globalchange.mit.edu/).

Uncertainty in Greenhouse Emissions and Costs of Atmospheric Stabilization

2008-11-01T00:00:00Z

Uncertainty in Greenhouse Emissions and Costs of Atmospheric Stabilization Webster, Mort D.; Paltsev, Sergey; Parsons, John E.; Reilly, John M.; Jacoby, Henry D. We explore the uncertainty in projections of emissions, and costs of atmospheric stabilization applying the MIT Emissions Prediction and Policy Analysis model, a computable general equilibrium model of the global economy. Monte Carlo simulation with Latin Hypercube Sampling is applied to draw 400 samples from probability distributions for 100 parameters in the EPPA model, including labor productivity growth rates, energy efficiency trends, elasticities of substitution, costs of advanced technologies, fossil fuel resource availability, and trends in emissions factors for urban pollutants. The resulting uncertainty in emissions and global costs is explored under a scenario assuming no climate policy and four different targets for stabilization of atmospheric greenhouse gas concentrations. We find that most of the IPCC emissions scenarios are outside the 90% probability range of emissions in the absence of climate policy, and are consistent with atmospheric stabilization scenarios. We find considerable uncertainty in the emissions prices under stabilization. For example, the CO2 price in 2060 under an emissions constraint targeted to achieve stabilization at 650 ppm has a 90% range of $14 to $88 per ton CO2, and a 450 ppm target in 2060 has a range of $241 to $758. We also explore the relative contribution of uncertainty in different parameters to the resulting uncertainty in emissions and costs and find that, despite the significant uncertainty in future energy supply technologies, the largest drivers of uncertainty in costs of atmospheric stabilization are energy demand parameters, including elasticities of substitution and energy efficiency trends. Abstract and PDF report are also available on the MIT Joint Program on the Science and Policy of Global Change website (http://globalchange.mit.edu/).

Marginal Abatement Costs and Marginal Welfare Costs for Greenhouse Gas Emissions Reductions: Results from the EPPA Model

2008-11-01T00:00:00Z

Marginal Abatement Costs and Marginal Welfare Costs for Greenhouse Gas Emissions Reductions: Results from the EPPA Model Morris, Jennifer; Paltsev, Sergey; Reilly, John M. Marginal abatement cost (MAC) curves, relationships between tons of emissions abated and the CO2 (or GHG) price, have been widely used as pedagogic devices to illustrate simple economic concepts such as the benefits of emissions trading. They have also been used to produce reduced form models to examine situations where solving the more complex model underlying the MAC is difficult. Some important issues arise in such applications: (1) are MAC relationships independent of what happens in other regions? (2) are MACs stable through time regardless of what policies have been implemented in the past?, and (3) can one approximate welfare costs from them? This paper explores the basic characteristics of MAC and marginal welfare cost (MWC) curves, deriving them using the MIT Emissions Prediction and Policy Analysis (EPPA) model. We find that, depending on the method used to construct them, MACs are affected by policies abroad. They are also dependent on policies in place in the past and depend on whether they are CO2-only or include all GHGs. Further, we find that MACs are, in general, not closely related to MWCs and therefore should not be used to derive estimates of welfare change. It would be a great convenience if a reduced-form response of a more complex model could be used to reliably conduct empirical analysis of climate change policy, but it appears that, at least as commonly constructed, MACs may be unreliable in replicating results of the parent model when used to simulate GHG policies. This is especially true if the policy simulations differ from the conditions under which the MACs were simulated. Care is needed to derive MACs under conditions closely related to the policy under consideration. In such a circumstance they may provide approximate estimates of CO2 or GHG prices for a given policy constraint. They remain a convenient way to visualize responses to a range of abatement levels. Abstract and PDF report are also available on the MIT Joint Program on the Science and Policy of Global Change website (http://globalchange.mit.edu/).

The Influence on Climate Change of Differing Scenarios for Future Development Analyzed Using the MIT Integrated Global System Model

2008-09-01T00:00:00Z

The Influence on Climate Change of Differing Scenarios for Future Development Analyzed Using the MIT Integrated Global System Model Prinn, Ronald G.; Paltsev, Sergey; Sokolov, Andrei P.; Sarofim, Marcus C.; Reilly, John M.; Jacoby, Henry D. A wide variety of scenarios for future development have played significant roles in climate policy discussions. This paper presents projections of greenhouse gas (GHG) concentrations, sea level rise due to thermal expansion and glacial melt, oceanic acidity, and global mean temperature increases computed with the MIT Integrated Global Systems Model (IGSM) using scenarios for 21st century emissions developed by three different groups: intergovernmental (represented by the Intergovernmental Panel on Climate Change), government (represented by the U.S. government Climate Change Science Program) and industry (represented by Royal Dutch Shell plc). In all these scenarios the climate system undergoes substantial changes. By 2100, the CO2 concentration ranges from 470 to 1020 ppm compared to a 2000 level of 365 ppm, the CO2-equivalent concentration of all greenhouse gases ranges from 550 to 1780 ppm in comparison to a 2000 level of 415 ppm, sea level rises by 24 to 56 cm relative to 2000 due to thermal expansion and glacial melt, oceanic acidity changes from a current pH of around 8 to a range from 7.63 to 7.91. The global mean temperature increases by 1.8 to 7.0 degrees C relative to 2000. Abstract and PDF report are also available on the MIT Joint Program on the Science and Policy of Global Change website (http://globalchange.mit.edu/).

The European Carbon Market in Action: Lessons from the First Trading Period Interim Report

2008-06-01T00:00:00Z

The European Carbon Market in Action: Lessons from the First Trading Period Interim Report Convery, Frank; Ellerman, A. Denny; De Perthuis, Christian The European Union Emissions Trading Scheme (EU ETS) is the largest greenhouse gas market ever established. The European Union is leading the world's first effort to mobilize market forces to tackle climate change. A precise analysis of the EU ETS's performance is essential to its success, as well as to that of future trading programs. The research program "The European Carbon Market in Action: Lessons from the First Trading Period," aims to provide such an analysis. It was launched at the end of 2006 by an international team led by Frank Convery, Christian De Perthuis and Denny Ellerman. This interim report presents the researchers' findings to date. It was prepared after the research program's second workshop, held in Washington DC in January 2008. The first workshop was held in Paris in April 2007. Two additional workshops will be held in Prague in June 2008 and in Paris in September 2008. The researchers' complete analysis will be published at the beginning of 2009. Abstract and PDF report are also available on the MIT Joint Program on the Science and Policy of Global Change website (http://globalchange.mit.edu/).

A Forward Looking Version of the MIT Emissions Prediction and Policy Analysis (EPPA) Model

2008-05-01T00:00:00Z

A Forward Looking Version of the MIT Emissions Prediction and Policy Analysis (EPPA) Model Babiker, Mustafa M.H.; Gurgel, Angelo C.; Paltsev, Sergey; Reilly, John M. This paper documents a forward looking multi-regional general equilibrium model developed from the latest version of the recursive-dynamic MIT Emissions Prediction and Policy Analysis (EPPA) model. The model represents full inter-temporal optimization (perfect foresight), which makes it possible to better address economic and policy issues such as borrowing and banking of GHG allowances, efficiency implications of environmental tax recycling, endogenous depletion of fossil resources, international capital flows, and optimal emissions abatement paths among others. It was designed with the flexibility to represent different aggregations of countries and regions, different horizon lengths, as well as the ability to accommodate different assumptions about the economy, in terms of economic growth, foreign trade closure, labor leisure choice, taxes on primary factors, vintaging of capital and data calibration. The forward-looking dynamic model provides a complementary tool for policy analyses, to assess the robustness of results from the recursive EPPA model, and to illustrate important differences in results that are driven by the perfect foresight behavior. We present some applications of the model that include the reference case and its comparison with the recursive EPPA version, as well as some greenhouse gas mitigation cases where we explore economic impacts with and without inter-temporal trade of permits. Abstract and PDF report are also available on the MIT Joint Program on the Science and Policy of Global Change website (http://globalchange.mit.edu/).

Constraining Climate Model Parameters from Observed 20th Century Changes

2008-04-01T00:00:00Z

Constraining Climate Model Parameters from Observed 20th Century Changes Forest, Chris Eliot; Stone, Peter H.; Sokolov, Andrei P. We present revised probability density functions for climate model parameters (effective climate sensitivity, the rate of deep-ocean heat uptake, and the strength of the net aerosol forcing) that are based on climate change observations from the 20th century. First, we compare observed changes in surface, upper-air, and deep-ocean temperature changes against simulations of 20th century climate in which the climate model parameters were systematically varied. The estimated 90% range of climate sensitivity is 2.0 to 5.0 K. The net aerosol forcing strength for the 1980s has 90% bounds of -0.70 to -0.27 W/m2. The rate of deep-ocean heat uptake corresponds to an effective diffusivity, Kv, with a 90% range of 0.04 to 4.1 cm2/s. Second, we estimate the effective climate sensitivity and rate of deep-ocean heat uptake for 11 of the IPCC AR4 AOGCMs. By comparing against the acceptable combinations inferred by the observations, we conclude that the rate of deep-ocean heat uptake for the majority of AOGCMs lie above the observationally based median value. This implies a bias in the predictions inferred from the IPCC models alone. This bias can be seen in the range of transient climate response from the AOGCMs as compared to that from the observational constraints. Abstract and PDF report are also available on the MIT Joint Program on the Science and Policy of Global Change website (http://globalchange.mit.edu/).

Analysis of U.S. Greenhouse Gas Tax Proposals

2008-04-01T00:00:00Z

Analysis of U.S. Greenhouse Gas Tax Proposals Metcalf, Gilbert E.; Paltsev, Sergey.; Reilly, John M.; Jacoby, Henry D.; Holak, Jennifer The U.S. Congress is considering a set of bills designed to limit the nation’s greenhouse gas (GHG) emissions. Several of these proposals call for a cap-and-trade system; others propose an emissions tax. This paper complements the analysis by Paltsev et al. (2007) of cap-and-trade bills and applies the MIT Emissions Prediction and Policy Analysis (EPPA) model to carry out an analysis of the tax proposals. Several lessons emerge from this analysis. First, a low starting tax rate combined with a low rate of growth in the tax rate will not reduce emissions significantly. Second, the costs of GHG reductions are reduced with the inclusion of non-CO2 gases in the carbon tax scheme. The costs of the Larson plan, for example, fall by 20% with inclusion of the other GHGs. Third, welfare costs of the policies can be affected by the rate of growth of the tax, even after controlling for cumulative emissions. Fourth, a carbon tax – like any form of carbon pricing – is regressive. However, general equilibrium considerations suggest that the short-run measured regressivity may be overstated. A portion of the carbon tax is passed back to workers, owners of equity, and resource owners. To the extent that relatively wealthy resource and equity owners bear some fraction of the tax burden, the regressivity will be reduced. Additionally, the regressivity can be offset with a carefully designed rebate of some or all of the revenue. Finally, the carbon tax bills that have been proposed or submitted are for the most part comparable to many of the carbon cap-and-trade proposals that have been suggested. Thus the choice between a carbon tax and cap-and-trade system can be made on the basis of considerations other than their effectiveness at reducing emissions over some control period. Either approach (or some hybrid of the two approaches) can be equally effective at reducing GHG emissions in the United States. Abstract in HTML and technical report in PDF available on the MIT Joint Program on the Science and Policy of Global Change website (http://mit.edu/globalchange/www/).

Impact of Sulfur and Carbonaceous Emissions from International Shipping on Aerosol Distributions and Direct Radiative Forcing

2008-04-01T00:00:00Z

Impact of Sulfur and Carbonaceous Emissions from International Shipping on Aerosol Distributions and Direct Radiative Forcing Wang, Chien.; Kim, Dongchul. We describe in this report an effort using the MIT/NCAR three-dimensional aerosol-climate model to study the impact of ship emissions on chemical composition and radiative forcing of aerosols. Our results indicate that international shipping can be a non-negligible factor in determining the radiative forcing of aerosols over specific regions with intensive ship activities. These places include the European, eastern Asian, and American coastal regions. The global mean aerosol radiative forcing caused by the ship emissions ranges from -12.5 to -23 mW/m^2, depending on whether the mixing between black carbon and sulfate is included in the model. However, over the aforementioned places, the radiative forcing resulting from ship emissions can be much more important in the total regional aerosol forcing. Abstract in HTML and technical report in PDF available on the MIT Joint Program on the Science and Policy of Global Change website (http://mit.edu/globalchange/www/).

Analysis of the Coal Sector under Carbon Constraints

2008-04-01T00:00:00Z

Analysis of the Coal Sector under Carbon Constraints McFarland, James R.; Paltsev, Sergey.; Jacoby, Henry D. Application of the MIT Emissions Prediction and Policy Analysis (EPPA) model to assessment of the future of coal under climate policy revealed the need for an improved representation of load dispatch in the representation of the electric sector. A new dispatching algorithm is described and the revised model is applied to an analysis of the future of coal use to 2050 and 2100 under alternative assumptions about CO2 prices, nuclear expansion and prices of natural gas. Particular attention is devoted to the potential role of coal-electric generation with CO2 capture and storage. An appendix provides a comparison of a subset of these results with and without the more detailed model of electric dispatch. Abstract in HTML and technical report in PDF available on the MIT Joint Program on the Science and Policy of Global Change website (http://mit.edu/globalchange/www/).

Estimating the Economic Cost of Sea-Level Rise

2008-04-01T00:00:00Z

Estimating the Economic Cost of Sea-Level Rise Sugiyama, Masahiro.; Nicholls, Robert J.; Vafeidis, Athanasios To improve the estimate of economic costs of future sea-level rise associated with global climate change, this report generalizes the sea-level rise cost function originally proposed by Fankhauser, and applies it to a new database on coastal vulnerability developed as part of the Dynamic Interactive Vulnerability Assessment (DIVA) tool. An analytic expression for the generalized sea-level rise cost function is obtained to explore the effect of various spatial distributions of capital and nonlinear sea-level rise scenarios. With its high spatial resolution, the DIVA database shows that capital is usually highly spatially concentrated along a nation’s coastline, and that previous studies, which assumed linear marginal capital loss for lack of this information, probably overestimated the fraction of a nation’s coastline to be protected and hence protection cost. In addition, the new function can treat a sea-level rise scenario that is nonlinear in time. As a nonlinear sea-level rise scenario causes more costs in the future than an equivalent linear sea-level rise scenario, using the new equation with a nonlinear scenario also reduces the estimated damage and protection fraction through discounting of the costs in later periods. Numerical calculations are performed, applying the cost function to the DIVA database and socioeconomic scenarios from the MIT Emissions Prediction and Policy Analysis (EPPA) model. The effect of capital concentration substantially decreases protection cost and capital loss compared with previous studies, but not wetland loss. The use of a nonlinear sea-level rise scenario further reduces the total cost because the cost is postponed into the future. Abstract in HTML and technical report in PDF available on the MIT Joint Program on the Science and Policy of Global Change website (http://mit.edu/globalchange/www/).

Potential Land Use Implications of a Global Biofuels Industry

2008-03-01T00:00:00Z

Potential Land Use Implications of a Global Biofuels Industry Gurgel, Angelo C.; Reilly, John M.; Paltsev, Sergey. In this paper we investigate the potential production and implications of a global biofuels industry. We develop alternative approaches to the introduction of land as an economic factor input, in value and physical terms, into a computable general equilibrium framework. Both approach allows us to parameterize biomass production in a manner consistent with agro-engineering information on yields and a “second generation” cellulosic biomass conversion technology. We explicitly model land conversion from natural areas to agricultural use in two different ways: in one approach we introduce a land supply elasticity based on observed land supply responses and in the other we consider only the direct cost of conversion. We estimate biofuels production at the end of the century will reach 220 to 270 exajoules in a reference scenario and 320 to 370 exajoules under a global effort to mitigate greenhouse gas emissions. The version with the land supply elasticity allows much less conversion of land from natural areas, forcing intensification of production, especially on pasture and grazing land, whereas the pure conversion cost model leads to significant deforestation. The observed land conversion response we estimate may be a short-term response that does not fully reflect the effect of long-run pressure to convert land if rent differentials are sustained over 100 years. These different approaches emphasize the importance of reflecting the non-market value of land more fully in the modeling of the conversion decision. Abstract in HTML and technical report in PDF available on the MIT Joint Program on the Science and Policy of Global Change website (http://mit.edu/globalchange/www/).

Modeling the Prospects for Hydrogen Powered Transportation Through 2100

2008-02-01T00:00:00Z

Modeling the Prospects for Hydrogen Powered Transportation Through 2100 Sandoval, Reynaldo.; Karplus, Valerie J.; Paltsev, Sergey.; Reilly, John M. Hydrogen fueled transportation has been proposed as a low carbon alternative to the current gasoline-powered fleet. Using a computable general equilibrium model of the world economy we explore the economic viability of hydrogen transportation in several different tax and carbon dioxide stabilization policy scenarios. We represent the capital, labor, fuel and other costs of hydrogen production and hydrogen powered vehicles in the economic model. We examine scenarios where the hydrogen fuel price and vehicle cost are varied over a wide range to evaluate what technology improvements would be needed, in terms of cost reductions, for hydrogen vehicles to penetrate the market. We consider scenarios with and without climate policy, and in competition with other reduced-carbon fuel substitutes, such as ethanol-blend fuels. We find that hydrogen-powered fuel-cell vehicles could make a significant contribution to de-carbonization of the transportation fuel cycle if production of hydrogen itself is not carbon-intensive. Cost targets needed for the technology to penetrate in the USA are such that the hydrogen fuel would need to be in the range of 1 to 1.7 times the 1997 price of gasoline and the vehicle mark-up above an average fuel cell automobile would need no more than 1.3 to 1.5 times an average conventional vehicle. At the lower end of these cost ranges, the vehicle fleet could be competitive by 2020 but at the upper end we would only see entry of the fleet toward the end of the century. High fuel taxes in Europe makes fuel-efficient hydrogen fuel cell technology more competitive there than in the USA. Along with cost reductions, these results assume that technical issues are solved and that market hurdles of establishing the fuel distribution system are overcome. For those involved in hydrogen vehicle research this analysis provides cost targets that would need to met and, given they are achieved, an idea of when vehicles could be competitive and under what conditions. Abstract in HTML and technical report in PDF available on the MIT Joint Program on the Science and Policy of Global Change website (http://mit.edu/globalchange/www/).

Climate Change, Mortality, and Adaptation: Evidence from Annual Fluctuations in Weather in the U.S.

2007-08-01T00:00:00Z

Climate Change, Mortality, and Adaptation: Evidence from Annual Fluctuations in Weather in the U.S. Deschenes, Olivier; Greenstone, Michael This paper produces the first large-scale estimates of the U.S. health related welfare costs due to climate change. Using the presumably random year-to-year variation in temperature and two state of the art climate models, the analysis suggests that under a “business as usual” scenario climate change will lead to an increase in the overall U.S. annual mortality rate ranging from 0.5% to 1.7% by the end of the 21st century. These overall estimates are statistically indistinguishable from zero, although there is evidence of statistically significant increases in mortality rates for some subpopulations, particularly infants. As the canonical Becker-Grossman health production function model highlights, the full welfare impact will be reflected in health outcomes and increased consumption of goods that preserve individuals’ health. Individuals’ likely first compensatory response is increased use of air conditioning; the analysis indicates that climate change would increase U.S. annual residential energy consumption by a statistically significant 15% to 30% ($15 to $35 billion in 2006 dollars) at the end of the century. It seems reasonable to assume that the mortality impacts would be larger without the increased energy consumption. Further, the estimated mortality and energy impacts likely overstate the long-run impacts on these outcomes, since individuals can engage in a wider set of adaptations in the longer run to mitigate costs. Overall, the analysis suggests that the health related welfare costs of higher temperatures due to climate change are likely to be quite modest in the U.S. Abstract in HTML and technical report in PDF available on the Massachusetts Institute of Technology Joint Program on the Science and Policy of Global Change website (http://mit.edu/globalchange/www/).

Energy Scenarios for East Asia: 2005-2025

2007-06-01T00:00:00Z

Energy Scenarios for East Asia: 2005-2025 Paltsev, Sergey; Reilly, John M. We describe several scenarios for economic development and energy use in East Asia based on the MIT Emissions Prediction and Policy Analysis (EPPA) model, a computable general equilibrium model of the world economy. Historic indicators for Asian economic growth, energy use, and energy intensity are discussed. In the Baseline scenario, energy use in East Asia is projected to increase from around 120 EJ in 2005 to around 220 EJ in 2025. Alternative scenarios were developed to consider: (1) How fast might energy demand grow in East Asia and how does it depend on key uncertainties? (2) Do rising prices for energy affect growth in the region? (3) Would growth in East Asia have a substantial effect on world energy markets? (4) Would development of regional gas markets have substantial effects on energy use in the region and on gas markets in other regions? Briefly, we find that with more rapid economic growth, demand in East Asia could reach 430 EJ by 2025, almost twice the level in the Baseline; rising energy prices place a drag on growth of countries in the region of 0.2 to 0.6% per year; world crude oil markets could be substantially affected by demand growth in the region, with the price effect being as much as $25 per barrel in 2025; and development of regional gas markets could expand gas use in East Asia while leading to higher gas prices in Europe. Abstract in HTML and technical report in PDF available on the Massachusetts Institute of Technology Joint Program on the Science and Policy of Global Change website (http://mit.edu/globalchange/www/).

Consequences of Considering Carbon/Nitrogen Interactions on the Feedbacks between Climate and the Terrestrial Carbon Cycle

2007-06-01T00:00:00Z

Consequences of Considering Carbon/Nitrogen Interactions on the Feedbacks between Climate and the Terrestrial Carbon Cycle Sokolov, Andrei P.; Kicklighter, David W.; Melillo, Jerry M.; Felzer, Benjamin; Schlosser, C. Adam; Cronin, Timothy W. A number of observational studies indicate that carbon sequestration by terrestrial ecosystems in a world with an atmosphere richer in carbon dioxide and a warmer climate depends on the interactions between the carbon and nitrogen cycles. However, most terrestrial ecosystem models being used in climate-change assessments do not take into account these interactions. Here we explore how carbon/nitrogen interactions in terrestrial ecosystems affect feedbacks to the climate system using the MIT Integrated Global Systems Model (IGSM) and its terrestrial ecosystems submodel, the Terrestrial Ecosystems Model (TEM). We use two versions of TEM, one with (standard TEM) and one without (carbon-only TEM) carbon/nitrogen interactions. Feedbacks between climate and the terrestrial carbon cycle are estimated by comparing model response to an increase in atmospheric CO2 concentration with and without climate change. Overall, for small or moderate increases in surface temperatures, the terrestrial biosphere simulated by the standard TEM takes up less atmospheric carbon than the carbon-only version, resulting in a larger increase in atmospheric CO2 concentration for a given amount of carbon emitted. With strong surface warming, the terrestrial biosphere simulated by the standard TEM may still become a carbon source early in the 23rd century. Our simulations also show that consideration of carbon/nitrogen interactions not only limits the effect of CO2 fertilization in the absence of climate change, but also changes the sign of the carbon feedback with climate change. In the simulations with the carbon-only version of TEM, surface warming significantly reduces carbon sequestration in both vegetation and soil, leading to a positive carbon-cycle feedback to the climate system. However, in simulations with standard TEM, the increased decomposition of soil organic matter with higher temperatures releases soil nitrogen to stimulate plant growth and carbon storage in the vegetation that is greater than the carbon lost from soil. As a result, sequestration of carbon in terrestrial ecosystems increases, in comparison to the fixed climate case, and the carbon cycle feedback to the climate system becomes negative for much of the next three centuries. Abstract in HTML and technical report in PDF available on the Massachusetts Institute of Technology Joint Program on the Science and Policy of Global Change website (http://mit.edu/globalchange/www/).

U.S. Greenhouse Gas Cap-and-Trade Proposals: Application of a Forward-Looking Computable General Equilibrium Model

2007-06-01T00:00:00Z

U.S. Greenhouse Gas Cap-and-Trade Proposals: Application of a Forward-Looking Computable General Equilibrium Model Gurgel, Angelo C.; Paltsev, Sergey; Reilly, John M.; Metcalf, Gilbert E. We develop a forward-looking version of the MIT Emissions Prediction and Policy Analysis (EPPA) model, and apply it to examine the economic implications of proposals in the U.S. Congress to limit greenhouse gas (GHG) emissions. We find that the abatement path and CO2-equivalent (CO2-e) price in the forward-looking model are quite similar to that of the recursive model, implying that the simulation of banking behavior in the recursive model by forcing the CO2-e price to rise at the discount rate approximates fairly well the banking result obtained with the forward-looking model. We find, however, that shocks in consumption path are smoothed out in the forward-looking model and that the lifetime welfare cost of GHG policy is lower than in the recursive model, results we would expect to find given that the forward-looking model can fully optimize over time. The forward-looking model allows us to explore issues for which it is uniquely well-suited, including revenue-recycling, early action crediting, and the role of a technology backstop. We find (1) capital tax recycling to be more welfare-cost reducing than labor tax recycling because of its long term effect on economic growth, (2) potentially substantial incentives for early action credits relative to emission levels in years after a policy is announced but before it is implemented that, however, when spread over the full horizon of the policy do not have a substantial effect on lifetime welfare cost or the CO2-e price, and (3) strong effects on estimates of near-term welfare costs depending on exactly how a backstop technology is represented, indicating the problematic aspects of focusing on short-term welfare costs in a forward-looking model unless there is some confidence that the backstop technology is realistically represented. Abstract in HTML and technical report in PDF available on the Massachusetts Institute of Technology Joint Program on the Science and Policy of Global Change website (http://mit.edu/globalchange/www/).

Global Economic Effects of Changes in Crops, Pasture, and Forests due to Changing Climate, Carbon Dioxide, and Ozone

2007-05-01T00:00:00Z

Global Economic Effects of Changes in Crops, Pasture, and Forests due to Changing Climate, Carbon Dioxide, and Ozone Reilly, John M.; Paltsev, Sergey.; Felzer, Benjamin Seth.; Wang, Xiaodong.; Kicklighter, David W.; Melillo, Jerry M.; Prinn, Ronald G.; Sarofim, Marcus C.; Sokolov, Andrei P.; Wang, Chien. Multiple environmental changes will have consequences for global vegetation. To the extent that crop yields and pasture and forest productivity are affected there can be important economic consequences. We examine the combined effects of changes in climate, increases in carbon dioxide, and changes in tropospheric ozone on crop, pasture, and forest lands and the consequences for the global and regional economies. We examine scenarios where there is limited or little effort to control these substances, and policy scenarios that limit emissions of CO2 and ozone precursors. We find the effects of climate and CO2 to be generally positive, and the effects of ozone to be very detrimental. Unless ozone is strongly controlled damage could offset CO2 and climate benefits. We find that resource allocation among sectors in the economy, and trade among countries, can strongly affect the estimate of economic effect in a country. Abstract in HTML and technical report in PDF available on the Massachusetts Institute of Technology Joint Program on the Science and Policy of Global Change website (http://mit.edu/globalchange/www/).

Relative Roles of Climate Sensitivity and Forcing in Defining the Ocean Circulation Response to Climate Change

2007-05-01T00:00:00Z

Relative Roles of Climate Sensitivity and Forcing in Defining the Ocean Circulation Response to Climate Change Scott, Jeffery R.; Sokolov, Andrei P.; Stone, Peter H.; Webster, Mort D. The response of the ocean’s meridional overturning circulation (MOC) to increased greenhouse gas forcing is examined using a coupled model of intermediate complexity, including a dynamic 3D ocean subcomponent. Parameters are the increase in CO2 forcing (with stabilization after a specified time interval) and the model’s climate sensitivity. In this model, the cessation of deep sinking in the north “Atlantic” (hereinafter, a “collapse”), as indicated by changes in the MOC, behaves like a simple bifurcation. The final surface air temperature (SAT) change, which is closely predicted by the product of the radiative forcing and the climate sensitivity, determines whether a collapse occurs. The initial transient response in SAT is largely a function of the forcing increase, with higher sensitivity runs exhibiting delayed behavior; accordingly, high CO2-low sensitivity scenarios can be assessed as a recovering or collapsing circulation shortly after stabilization, whereas low CO2-high sensitivity scenarios require several hundred additional years to make such a determination. We also systemically examine how the rate of forcing, for a given CO2 stabilization, affects the ocean response. In contrast with previous studies based on results using simpler ocean models, we find that except for a narrow range of marginally stable to marginally unstable scenarios, the forcing rate has little impact on whether the run collapses or recovers. In this narrow range, however, forcing increases on a time scale of slow ocean advective processes results in weaker declines in overturning strength and can permit a run to recover that would otherwise collapse. Abstract in HTML and technical report in PDF available on the Massachusetts Institute of Technology Joint Program on the Science and Policy of Global Change website (http://mit.edu/globalchange/www/).

A Global Land System Framework for Integrated Climate-Change Assessments

2007-05-01T00:00:00Z

A Global Land System Framework for Integrated Climate-Change Assessments Schlosser, C. Adam; Kicklighter, David; Sokolov, Andrei Land ecosystems play a major role in the global cycles of energy, water, carbon and nutrients. A Global Land System (GLS) framework has been developed for the Integrated Global Systems Model Version 2 (IGSM2) to simulate the coupled biogeophysics and biogeochemistry of these ecosystems, as well as the interactions of these terrestrial processes with the climate system. The GLS framework has resolved a number of water and energy cycling deficiencies and inconsistencies introduced in IGSM1. In addition, a new representation of global land cover and classification as well as soil characteristics has been employed that ensures a consistent description of the global land surface amongst all the land components of the IGSM2. Under this new land cover classification system, GLS is run for a mosaic of land cover types within a latitudinal band defined by the IGSM2 atmosphere dynamics and chemistry sub-model. The GLS shows notable improvements in the representation of land fluxes and states of water and energy over the previous treatment of land processes in the IGSM1. In addition, the zonal features of simulated carbon fluxes as well as key trace gas emissions of methane and nitrous oxide are comparable to estimates based on higher resolution models constrained by observed climate forcing. Given this, the GLS framework represents a key advance in the ability of the IGSM to faithfully represent coupled terrestrial processes to the climate system, and is well poised to support more robust two-way feedbacks of natural and managed hydrologic and ecologic systems with the climate and socio-economic components of the IGSM2. Abstract in HTML and technical report in PDF available on the Massachusetts Institute of Technology Joint Program on the Science and Policy of Global Change website (http://mit.edu/globalchange/www/).

Assessment of U.S. Cap-and-Trade Proposals

2007-04-01T00:00:00Z

Assessment of U.S. Cap-and-Trade Proposals Paltsev, Sergey; Reilly, John M.; Jacoby, Henry D.; Gurgel, Angelo C.; Metcalf, Gilbert E.; Sokolov, Andrei P.; Holak, Jennifer F. The MIT Emissions Prediction and Policy Analysis model is applied to an assessment of a set of cap-and-trade proposals being considered by the U.S. Congress in spring 2007. The bills specify emissions reductions to be achieved through 2050 for the standard six-gas basket of greenhouse gases. They fall into two groups: one specifies emissions reductions of 50% to 80% below 1990 levels by 2050; the other establishes a tightening target for emissions intensity and stipulates a time-path for a “safety valve” limit on the emission price that approximately stabilizes U.S. emissions at the 2008 level. A set of three synthetic emissions paths are defined that span the range of stringency of these proposals, and these “core” cases are analyzed for their consequences in terms of emissions prices, effects on energy markets, welfare cost, the potential revenue generation if allowances are auctioned and the gains if permit revenue were used to reduce capital or labor taxes. Initial period prices for the first group of proposals, in carbon dioxide equivalents, are estimated between $30 and $50 per ton CO2-e depending on where each falls in the 50% to 80% range, with these prices rising by a factor of four by 2050. Welfare costs are less than 0.5% at the start, rising in the most stringent case to near 2% in 2050. If allowances were auctioned these proposals could produce revenue between $100 billion and $500 billion per year depending on the case. Emissions prices for the second group, which result from the specified safety-valve path, rise from $7 to $40 over the study period, with welfare effects rising from near zero to approximately a 0.5% loss in 2050. Revenue in these proposals depends on how many allowances are freely distributed. To analyze these proposals assumptions must be made about mitigation effort abroad, and simulations are provided to illuminate terms-of-trade effects that influence the emissions prices and welfare effects, and even the environmental effectiveness, of U.S. actions. Sensitivity tests also are provided of several of the design features imposed in the “core” scenarios including the role of banking, the specification of less than complete coverage of economic sectors, and the development of international permit trading. Also, the effects of alternative assumptions about nuclear power development are explored. Of particular importance in these simulations is the role of biofuels, and analysis is provided of the implications of these proposals for land use and agriculture. Finally, the U.S. proposals, and the assumptions about effort elsewhere, are extended to 2100 to allow exploration of the potential role of these bills in the longer-term challenge of reducing climate change risk. Simulations using the MIT Integrated System Model show that the 50% to 80% targets are consistent with global goals of atmospheric stabilization at 450 to 550 ppmv CO2 but only if other nations, including the developing countries, follow. Abstract in HTML and technical report in PDF available on the Massachusetts Institute of Technology Joint Program on the Science and Policy of Global Change website (http://mit.edu/globalchange/www/).

Biomass Energy and Competition for Land

2007-04-01T00:00:00Z

Biomass Energy and Competition for Land Reilly, John; Paltsev, Sergey We describe an approach for incorporating biomass energy production and competition for land into the MIT Emissions Prediction and Policy Analysis (EPPA) model, a computable general equilibrium model of the world economy, that has been widely used to study climate change policy. We examine multiple scenarios where greenhouse gas emissions are abated or not. The global increase in biomass energy use in a reference scenario (without climate change policy) is about 30 EJ/year by 2050 and about 180 EJ/year by 2100. This deployment is driven primarily by a world oil price that in the year 2100 is over 4.5 times the price in the year 2000. In the scenarios of stabilization of greenhouse gas concentrations, the global biomass energy production increases to 50-150 EJ/year by 2050 and 220-250 EJ/year by 2100. The estimated area of land required to produce 180-250 EJ/year is about 2Gha, which is an equivalent of the current global crop area. In the USA we find that under a stringent climate policy biofuels could supply about 55% of USA liquid fuel demand, but if the biofuels were produced domestically the USA would turn from a substantial net exporter of agricultural goods ($20 billion) to a large net importer ($80 billion). The general conclusion is that the scale of energy use in the USA and the world relative to biomass potential is so large that a biofuel industry that was supplying a substantial share of liquid fuel demand would have very significant effects on land use and conventional agricultural markets. Abstract in HTML and technical report in PDF available on the Massachusetts Institute of Technology Joint Program on the Science and Policy of Global Change website (http://mit.edu/globalchange/www/).

Heavier Crude, Changing Demand for Petroleum Fuels, Regional Climate Policy, and the Location of Upgrading Capacity:

2007-04-01T00:00:00Z

Heavier Crude, Changing Demand for Petroleum Fuels, Regional Climate Policy, and the Location of Upgrading Capacity: Reilly, John; Paltsev, Sergey; Choumert, Frederic The crude slate is likely to become heavier in the future with greater reliance on bitumens, tar sands, heavy oils, and eventually possibly shale oil. Under standard refining processes these crude oil sources produce a larger fraction of heavy products. At the same time, petroleum product demand growth is likely to disproportionately favor mid-weight products because of the strongly growing demand for transportation fuels including diesel, jet fuel, and gasoline. This will create a significant demand for new upgrading capacity in the refinery sector, and these upgrading facilities are themselves a significant source of carbon emissions. Using a version of the MIT Emissions Prediction and Policy Analysis (EPPA) model that separately considers five petroleum products we examine the need for, and the location of, refinery upgrading capacity under significant carbon policy in developed countries but not in developing countries. The results show that a carbon policy leads to a shift of most of the investment in upgrading capacity to developing countries, where the cost of carbon control is avoided, resulting in significant carbon leakage. Abstract in HTML and technical report in PDF available on the Massachusetts Institute of Technology Joint Program on the Science and Policy of Global Change website (http://mit.edu/globalchange/www/).

Technical Change, Investment and Energy Intensity

2007-03-01T00:00:00Z

Technical Change, Investment and Energy Intensity Kratena, Kurt This paper analyzes the role of different components of technical change on energy intensity by applying a Translog variable cost function setting to the new EU KLEMS dataset for 3 selected EU countries (Italy, Finland and Spain). The framework applied represents an accounting of technical change components, comprising autonomous as well as embodied and induced technical change. The inducement of embodied technical change is introduced by an equation for the physical capital stock that is a fixed factor in the short-run. The dataset on capital services and user costs of capital in EUKLEMS enables explaining capital accumulation depending on factor prices. The model can be used for explaining and tracing back the long-run impact of prices and technical change on energy intensity. Abstract in HTML and technical report in PDF available on the Massachusetts Institute of Technology Joint Program on the Science and Policy of Global Change website (http://mit.edu/globalchange/www/).

Federal Tax Policy Towards Energy

2007-01-01T00:00:00Z

Federal Tax Policy Towards Energy Metcalf, Gilbert E. On Aug. 8, 2005, President Bush signed the Energy Policy Act of 2005 (PL 109-58). This was the first major piece of energy legislation enacted since 1992 following five years of Congressional efforts to pass energy legislation. Among other things, the law contains tax incentives worth over $14 billion between 2005 and 2015. These incentives represent both pre-existing initiatives that the law extends as well as new initiatives. In this paper I survey federal tax energy policy focusing both on programs that affect energy supply and demand. I briefly discuss the distributional and incentive impacts of many of these incentives. In particular, I make a rough calculation of the impact of tax incentives for domestic oil production on world oil supply and prices and find that the incentives for domestic production have negligible impact on world supply or prices despite the United States being the third largest oil producing country in the world. Finally, I present results from a model of electricity pricing to assess the impact of the federal tax incentives directed at electricity generation. I find that nuclear power and renewable electricity sources benefit substantially from accelerated depreciation and that the production and investment tax credits make clean coal technologies cost competitive with pulverized coal and wind and biomass cost competitive with natural gas. Abstract in HTML and technical report in PDF available on the Massachusetts Institute of Technology Joint Program on the Science and Policy of Global Change website (http://mit.edu/globalchange/www/).

Over-Allocation or Abatement? A Preliminary Analysis of the EU Emissions Trading Scheme Based on the 2005 Emissions Data

2006-12-01T00:00:00Z

Over-Allocation or Abatement? A Preliminary Analysis of the EU Emissions Trading Scheme Based on the 2005 Emissions Data Ellerman, A. Denny.; Buchner, Barbara. This paper provides an initial analysis of the European Union Emissions Trading Scheme (EU ETS) based on the installation-level data for verified emissions and allowance allocations in the first trading year. Those data, released on May 15, 2006, and subsequent updates revealed that CO2 emissions were about 4% lower than the allocated allowances. The main objective of the paper is to shed light on the extent to which over-allocation and abatement have taken place in 2005. We propose a measure by which over-allocation can be judged and provide estimates of abatement based on emissions data and indicators of economic activity as well as trends in energy and carbon intensity. Finally, we discuss the insights and implications that emerge from this tentative assessment. Abstract in HTML and technical report in PDF available on the Massachusetts Institute of Technology Joint Program on the Science and Policy of Global Change website (http://mit.edu/globalchange/www/).

The Allocation of European Union Allowances: Lessons, Unifying Themes and General Principles

2006-10-01T00:00:00Z

The Allocation of European Union Allowances: Lessons, Unifying Themes and General Principles Buchner, Barbara.; Carraro, Carlo.; Ellerman, A. Denny. A critical issue in dealing with climate change is deciding who has a right to emit carbon dioxide (CO2), and under what conditions, when those emissions are limited. The European Union Emissions Trading Scheme (EU ETS) is the world’s first large experiment with an emission trading system for CO2 and it is likely to be copied by others if there is to be a global regime for limiting greenhouse gas emissions. This paper provides the first in-depth description and analysis of the process by which rights to emit carbon dioxide were created and distributed in the EU ETS. The main objective of the paper is to distill the lessons and general principles to be learned from the allocation of allowances in the EU ETS, i.e. in the world’s first experience with allocating carbon allowances to sub-national entities. We discuss the lessons and unifying observations that emerge from this experience and provide some insights on what seem to be more general principles informing the allocation process and on what are the global implications of the EU ETS. Abstract in HTML and technical report in PDF available on the Massachusetts Institute of Technology Joint Program on the Science and Policy of Global Change website (http://mit.edu/globalchange/www/).

Directed Technical Change and the Adoption of CO2 Abatement Technology: The Case of CO2 Capture and Storage

2006-08-01T00:00:00Z

Directed Technical Change and the Adoption of CO2 Abatement Technology: The Case of CO2 Capture and Storage Otto, Vincent M.; Reilly, John M. This paper studies the cost effectiveness of combining traditional environmental policy, such as CO2 trading schemes, and technology policy that has aims of reducing the cost and speeding the adoption of CO2 abatement technology. For this purpose, we develop a dynamic general equilibrium model that captures empirical links between CO2 emissions associated with energy use, directed technical change and the economy. We specify CO2 capture and storage (CCS) as a discrete CO2 abatement technology. We find that combining CO2-trading schemes with an adoption subsidy is the most effective instrument to induce adoption of the CCS technology. Such a subsidy directly improves the competitiveness of the CCS technology by compensating for its markup over the cost of conventional electricity. Yet, introducing R&D subsidies throughout the entire economy leads to faster adoption of the CCS technology as well and in addition can be cost effective in achieving the abatement target. Abstract in HTML and technical report in PDF available on the Massachusetts Institute of Technology Joint Program on the Science and Policy of Global Change website (http://mit.edu/globalchange/www/).

Energy Conservation in the United States: Understanding its Role in Climate Policy

2006-08-01T00:00:00Z

Energy Conservation in the United States: Understanding its Role in Climate Policy Metcalf, Gilbert E. Efforts to reduce carbon emissions significantly will require considerable improvements in energy intensity, the ratio of energy consumption to economic activity. Improvements in energy intensity over the past thirty years suggest great possibilities for energy conservation: current annual energy consumption avoided due to declines in energy intensity since 1970 substantially exceed current annual domestic energy supply. While historic improvements in energy intensity suggest great scope for energy conservation in the future, I argue that estimates of avoided energy costs due to energy conservation are overly optimistic. Avoided costs are likely to be significantly higher than estimates from recent energy technology studies suggest once behavioral responses are taken into account. I then analyze a data set on energy intensity in the United States at the state level between 1970 and 2001 to disentangle the key elements of energy efficiency and economic activity that drive changes in energy intensity. Rising per capita income plays an important role in lower energy intensity. Higher energy prices also are important. Price and income predominantly influence intensity through changes in energy efficiency rather than through changes in economic activity. Abstract in HTML and technical report in PDF available on the Massachusetts Institute of Technology Joint Program on the Science and Policy of Global Change website (http://mit.edu/globalchange/www/).

Greenhouse Gas Mitigation as a Structural Change and Policies that Offset Its Depressing Effects

2006-07-01T00:00:00Z

Greenhouse Gas Mitigation as a Structural Change and Policies that Offset Its Depressing Effects Babiker, Mustafa H.M.; Eckaus, Richard S. The current economic modeling of emissions limitations does not embody economic features that are likely to be particularly important in the short term, yet the politics of limiting greenhouse gas emissions are often dominated by relatively short term considerations. Moreover, only a few of these studies also consider policies that would offset the negative direct economic effects of those restrictions. This paper models the effects of restrictions on greenhouse gas emissions while embodying two of the most significant types of short term economic imperfections: sectoral rigidities in labor mobility and sectoral rigidities in wage adjustments. A labor policy is also analyzed that would reduce the direct negative economic effects of emissions restrictions. For plausible estimates of the parameters, the model shows that with the labor market imperfections, if there were no offsetting policies, there would be as much as 4 per cent reductions in GNP in the U.S. in the first ten years after emissions restrictions were imposed. However, if there were two policies, instead of just one: a counteracting labor market policy, as well as the emissions restrictions, the negative direct economic effects could be completely eliminated. Abstract in HTML and technical report in PDF available on the Massachusetts Institute of Technology Joint Program on the Science and Policy of Global Change website (http://mit.edu/globalchange/www/).

Bringing Transportation into a Cap-and-Trade Regime

2006-06-01T00:00:00Z

Bringing Transportation into a Cap-and-Trade Regime Ellerman, A. Denny.; Jacoby, Henry D.; Zimmerman, Martin B. The U.S. may at some point adopt a national cap-and-trade system for greenhouse gases, and if and when that happens the system of CAFE regulation of vehicle design very likely could still be in place. Imposed independently these two systems can lead to economic waste. One way to avoid the inefficiency is to integrate the two systems by allowing emissions trading between them. Two possible approaches to potential linkage are explored here, along with a discussion of ways to guard against violation under such a trading regime of vehicle standards that may be justified by non-climate objectives. At a minimum, implementation of a U.S. cap-and-trade system is several years in the future, so we also suggest intermediate measures that would gain some of the advantages of an integrated system and smooth the way to ultimate interconnection. Abstract in HTML and technical report in PDF available on the Massachusetts Institute of Technology Joint Program on the Science and Policy of Global Change website (http://mit.edu/globalchange/www/).

Modeling Climate Feedbacks to Energy Demand: The Case of China

2006-06-01T00:00:00Z

Modeling Climate Feedbacks to Energy Demand: The Case of China Asadoorian, Malcolm O.; Eckaus, Richard S.; Schlosser, C. Adam. This paper is an empirical investigation of the effects of climate on the use of electricity by consumers and producers in urban and rural areas within China. It takes advantage of an unusual combination of temporal and regional data sets in order to estimate temperature, as well as price and income elasticities of electricity demand. The estimated positive temperature/electric power feedback implies a continually increasing use of energy to produce electric power which, in China, is primarily based on coal. In the absence of countervailing measures, this will contribute to increased emissions, increased atmospheric concentrations of greenhouse gases, and increases in greenhouse warming. Abstract in HTML and technical report in PDF available on the Massachusetts Institute of Technology Joint Program on the Science and Policy of Global Change website (http://mit.edu/globalchange/www/).

Directed Technical Change and Climate Policy

2006-04-01T00:00:00Z

Directed Technical Change and Climate Policy Otto, Vincent M.; Loeschel, Andreas; Reilly, John M. This paper studies the cost effectiveness of climate policy if there are technology externalities. For this purpose, we develop a forward-looking CGE model that captures empirical links between CO2 emissions associated with energy use, directed technical change and the economy. We find the cost-effective climate policy to include a combination of R&D subsidies and CO2 emission constraints, although R&D subsidies raise the shadow value of the CO2 constraint (i.e. CO2 price) because of a strong rebound effect from stimulating innovation. Furthermore, we find that CO2 constraints differentiated toward CO2-intensive sectors are more cost effective than constraints that generate uniform CO2 prices among sectors. Differentiated CO2 prices, through technical change and concomitant technology externalities, encourage growth in the non-CO2 intensive sectors and discourage growth in CO2-intensive sectors. Thus, it is cost effective to let the latter bear relatively more of the abatement burden. This result is robust to whether emission constraints, R&D subsidies or combinations of both are used to reduce CO2 emissions. Abstract in HTML and technical report in PDF available on the Massachusetts Institute of Technology Joint Program on the Science and Policy of Global Change website (http://mit.edu/globalchange/www/).

Estimating Probability Distributions from Complex Models with Bifurcations: The Case of Ocean Circulation Collapse

2006-03-01T00:00:00Z

Estimating Probability Distributions from Complex Models with Bifurcations: The Case of Ocean Circulation Collapse Webster, Mort David.; Scott, Jeffery.; Sokolov, Andrei P.; Stone, Peter H. Studying the uncertainty in computationally expensive models has required the development of specialized methods, including alternative sampling techniques and response surface approaches. However, existing techniques for response surface development break down when the model being studied exhibits discontinuities or bifurcations. One uncertain variable that exhibits this behavior is the thermohaline circulation (THC) as modeled in three-dimensional general circulation models. This is a critical uncertainty for climate change policy studies. We investigate the development of a response surface for studying uncertainty in THC using the Deterministic Equivalent Modeling Method, a stochastic technique using expansions in orthogonal polynomials. We show that this approach is unable to reasonably approximate the model response. We demonstrate an alternative representation that accurately simulates the model’s response, using a basis function with properties similar to the model’s response over the uncertain parameter space. This indicates useful directions for future methodological improvements. Abstract in HTML and technical report in PDF available on the Massachusetts Institute of Technology Joint Program on the Science and Policy of Global Change website (http://mit.edu/globalchange/www/).

The Value of Emissions Trading

2006-02-01T00:00:00Z

The Value of Emissions Trading Webster, Mort David.; Paltsev, Sergey.; Reilly, John M. This paper estimates the value of international emissions trading, focusing attention on a here-to-fore neglected component: its value as a hedge against uncertainty. Much analysis has been done of the Kyoto Protocol and other potential international greenhouse gas mitigation policies comparing the costs of achieving greenhouse gas emission targets with and without trading. These studies often show large cost reductions for all Parties under trading compared to a no trading case. We investigate the welfare gains of including emissions trading in the presence of uncertainty in economic growth rates, using both a partial equilibrium model based on marginal abatement cost curves and a computable general equilibrium model that allows consideration of the interaction of emissions trading with existing energy taxes and changes in terms of trade. We find that the hedge value of international trading is small relative to its value in reallocating emissions reductions when, as in the Kyoto Protocol, the burden-sharing scheme does not resemble a least-cost allocation. The Kyoto Protocol also allocated excess allowances to Russia, so-called “hot air,” and much of the value often attributed to emissions trading stems from other Parties having access to these extra allowances, which has the effect of lowering the aggregate emissions target. We also find that the effects of preexisting tax distortions and terms of trade dominate the hedge value of trading. We conclude that the primary value of emissions trading in international agreements is as a burden-sharing or wealth transfer mechanism and should be judged accordingly. Abstract in HTML and technical report in PDF available on the Massachusetts Institute of Technology Joint Program on the Science and Policy of Global Change website (http://mit.edu/globalchange/www/).

The Economic Impacts of Climate Change: Evidence from Agricultural Profits and Random Fluctuations of Weather

2006-01-01T00:00:00Z

The Economic Impacts of Climate Change: Evidence from Agricultural Profits and Random Fluctuations of Weather Deschenes, Olivier.; Greenstone, Michael. This paper measures the economic impact of climate change on agricultural land in the United States by estimating the effect of the presumably random year-to-year variation in temperature and precipitation on agricultural profits. Using long-run climate change predictions from the Hadley 2 Model, the preferred estimates indicate that climate change will lead to a $1.1 billion (2002$) or 3.4% increase in annual profits. The 95% confidence interval ranges from –$1.8 billion to $4.0 billion and the impact is robust to a wide variety of specification checks, so large negative or positive effects are unlikely. There is considerable heterogeneity in the effect across the country with California’s predicted impact equal to –$2.4 billion (or nearly 50% of state agricultural profits). Further, the analysis indicates that the predicted increases in temperature and precipitation will have virtually no effect on yields among the most important crops. These crop yield findings suggest that the small effect on profits is not due to short-run price increases. The paper also implements the hedonic approach that is predominant in the previous literature. We conclude that this approach may be unreliable, because it produces estimates of the effect of climate change that are very sensitive to seemingly minor decisions about the appropriate control variables, sample and weighting. Overall, the findings contradict the popular view that climate change will have substantial negative welfare consequences for the US agricultural sector. Abstract in HTML and technical report in PDF available on the Massachusetts Institute of Technology Joint Program on the Science and Policy of Global Change website (http://mit.edu/globalchange/www/).

Absolute vs. Intensity Limits for CO2 Emission Control: Performance Under Uncertainty

2006-01-01T00:00:00Z

Absolute vs. Intensity Limits for CO2 Emission Control: Performance Under Uncertainty Sue Wing, Ian.; Ellerman, A. Denny.; Song, Jaemin. We elucidate the differences between absolute and intensity-based limits of CO2 emission when there is uncertainty about the future. We demonstrate that the two limits are identical under certainty, and rigorously establish their relative attractiveness under two criteria: preservation of expectations—the minimization of the difference between the actual level and the initial expectation of abatement associated with a one-shot emission target, and temporal stability—the minimization of the variance of abatement due to fluctuations in emissions and GDP over time. Empirical tests of these theoretical propositions indicate that intensity caps are preferable for a broad range of emission reduction commitments. This finding is robust for developing countries, but is more equivocal for developed economies. Abstract in HTML and technical report in PDF available on the Massachusetts Institute of Technology Joint Program on the Science and Policy of Global Change website (http://mit.edu/globalchange/www/).

Future Carbon Regulations and Current Investments in Alternative Coal-Fired Power Plant Designs

2005-12-01T00:00:00Z

Future Carbon Regulations and Current Investments in Alternative Coal-Fired Power Plant Designs Sekar, Ram C.; Parsons, John E.; Herzog, Howard J.; Jacoby, Henry D. This paper assesses the role of uncertainty over future U.S. carbon regulations in shaping the current choice of which type of power plant to build. The pulverized coal technology (PC) still offer the lowest cost power— assuming there is no need to control emissions of carbon. The integrated coal gasification combined cycle technology (IGCC) may be cheaper if carbon must be captured. Since a plant built now will be operated for many years, and since carbon regulations may be instituted in the future, a U.S. electric utility must make the current investment decision in light of the uncertain future regulatory rules. This paper shows how this decision is to be made. We start by describing the economics of the two key coal-fired power plant technologies, PC and IGCC. We then analyze the potential costs of future carbon regulations, including the costs of retrofitting the plant with carbon capture technology and the potential cost of paying charges for emissions. We present the economics of each design in the form of a cash flow spreadsheet yielding the present value cost, and show the results for different scenarios of emissions regulation. We then discuss how to incorporate uncertainty about the future regulation of carbon emissions into the decision to build one plant design or the other. As an aid to decision making, we provide some useful benchmarks for possible future regulation and show how these benchmarks relate back to the relative costs of the two technologies and the optimal choice for the power plant investment. Few of the scenarios widely referenced in the public discussion warrant the choice of the IGCC technology. Instead, the PC technology remains the least costly. The level of future regulation required to justify a current investment in the IGCC technology appears to be very aggressive, if not out of the question. However, the current price placed on carbon emissions in the European Trading System, is higher than these benchmarks. If it is any guide to possible future penalties for emissions in the U.S., then current investment in the IGCC technology is warranted. Abstract in HTML and technical report in PDF available on the Massachusetts Institute of Technology Joint Program on the Science and Policy of Global Change website (http://mit.edu/globalchange/www/).

Evaluating the Use of Ocean Models of Different Complexity in Climate Change Studies

2005-11-01T00:00:00Z

Evaluating the Use of Ocean Models of Different Complexity in Climate Change Studies Sokolov, Andrei P.; Dutkiewicz, Stephanie.; Stone, Peter H.; Scott, Jeffery. The study of the uncertainties in future climate projections requires large ensembles of simulations with different values of model characteristics that define its response to external forcing. These characteristic include climate sensitivity, strength of aerosol forcing and the rate of ocean heat uptake. The latter can be easily varied over a wide range in an anomaly diffusing ocean model (ADOM). The rate of heat uptake in a three-dimensional ocean general circulation model (OGCM) is, however, defined by large number of factors and is far more difficult to vary. Necessity to obtain a realistic ocean circulation places additional constraints, making it impossible to cover the range of values suggested by observations. As a result, a simpler model like an ADOM needs to be used in uncertainty studies. To evaluate the performance of the ADOM on different time scales we compare results of simulations with two versions of the MIT Integrated Global System Model (IGSM): one with a ADOM and the second with a full three-dimensional OCGM. Our results show that through the 20th and 21st century, the version of the IGSM with ADOM is able to reproduce important aspects of the climate response simulated by the version with the OCGM. However, the inability of the ADOM to depict feedbacks associated with the changes in the ocean circulation significantly affects its performance on the longer timescales. In particular, the ADOM overestimates sea level rise due to thermal expansion of the deep ocean. It also rather poorly depicts long term changes in oceanic carbon uptake, leading to underestimation of the atmospheric CO2 concentrations. Thus, the IGSM version with ADOM can be used to obtain probability distributions of changes in many of the important climate variables through the end of 21st century. On the other hand, studying longer-term climate change requires the use of the OGCM. Abstract in HTML and technical report in PDF available on the Massachusetts Institute of Technology Joint Program on the Science and Policy of Global Change website (http://mit.edu/globalchange/www/).

An Analysis of the European Emission Trading Scheme

2005-10-01T00:00:00Z

An Analysis of the European Emission Trading Scheme Reilly, John M.; Paltsev, Sergey. An international emissions trading system is a featured instrument in the Kyoto Protocol to the Framework Convention on Climate Change, designed to reduce emissions of greenhouse gases among major industrial countries. The US was the leading proponent of emissions trading in the negotiations leading up to the Protocol, with the European Union initially reluctant to embrace the idea. However the US withdrawal from the Protocol has greatly changed the nature of the agreement. One result is that the EU has moved rapidly ahead, establishing in 2003 the Emission Trading Scheme (ETS) for the period of 2005-2007. This Scheme was intended as a test designed to help its member states transition to a system that would lead to compliance with their Kyoto Protocol commitments, which cover the period 2008-2012. The ETS covers CO2 emissions from big industrial entities in the electricity, heat, and energy-intensive sectors. It is a system that itself is evolving as allocations, rules, and registries were still being finalized in some member states late into 2005, even though the system started in January of that year. We analyze the ETS using the MIT Emissions Prediction and Policy Analysis (EPPA) model. We find that a competitive carbon market clears at a carbon price of about 0.6 to 0.9 €/tCO2 (approximately 2 to 3 €/tC) for the 2005-2007 period in a base run of our model in line with many observers’ expectations who saw the cuts required under the system as very mild, but in sharp contrast to the actual history of trading prices, which have settled in the range of 20 to 25 €/tCO2 (approximately 70 to 90 €/tC) by the middle of 2005. In various comparison exercises the EPPA model’s estimates of carbon prices have been similar to that of other models, and so the contrast between projection and reality in the ETS raises questions regarding the potential real cost of emissions reductions vis-à-vis expectations previously formed based on results from the modeling community. While it is beyond the scope of this paper to reach firm conclusions on reasons for this difference, what happens over the next few years will have important implications for greenhouse gas emissions trading and so further analysis of the emerging European trading system will be crucial. Abstract in HTML and technical report in PDF available on the Massachusetts Institute of Technology Joint Program on the Science and Policy of Global Change website (http://mit.edu/globalchange/www/).

Estimated PDFs of Climate System Properties Including Natural and Anthropogenic Forcings

2005-09-01T00:00:00Z

Estimated PDFs of Climate System Properties Including Natural and Anthropogenic Forcings Forest, Chris Eliot.; Stone, Peter H.; Sokolov, Andrei P. We present revised probability density functions (PDF) for climate system properties (climate sensitivity, rate of deep-ocean heat uptake, and the net aerosol forcing strength) that include the effect on 20th century temperature changes of natural as well as anthropogenic forcings. The additional natural forcings, primarily the cooling by volcanic eruptions, affect the PDF by requiring a higher climate sensitivity and a lower rate of deep-ocean heat uptake to reproduce the observed temperature changes. The estimated 90% range of climate sensitivity is 2.4 to 9.2 K. The net aerosol forcing strength for the 1980s decade shifted towards positive values to compensate for the now included volcanic forcing with 90% bounds of -0.7 to -0.16 W/m2. The rate of deep-ocean heat uptake is also reduced with the effective diffusivity, Kv, ranging from 0.25 to 7.3 cm2/s. This upper bound implies that many coupled atmosphere-ocean GCMs mix heat into the deep ocean (below the mixed layer) too efficiently. Abstract in HTML and technical report in PDF available on the Massachusetts Institute of Technology Joint Program on the Science and Policy of Global Change website (http://mit.edu/globalchange/www/).

The MIT Emissions Prediction and Policy Analysis (EPPA) Model: Version 4

2005-08-01T00:00:00Z

The MIT Emissions Prediction and Policy Analysis (EPPA) Model: Version 4 Paltsev, Sergey.; Reilly, John M.; Jacoby, Henry D.; Eckaus, Richard S.; McFarland, James R.; Sarofim, Marcus C.; Asadoorian, Malcolm O.; Babiker, Mustafa H.M. The Emissions Prediction and Policy Analysis (EPPA) model is the part of the MIT Integrated Global Systems Model (IGSM) that represents the human systems. EPPA is a recursive-dynamic multi-regional general equilibrium model of the world economy, which is built on the GTAP dataset and additional data for the greenhouse gas and urban gas emissions. It is designed to develop projections of economic growth and anthropogenic emissions of greenhouse related gases and aerosols. The main purpose of this report is to provide documentation of a new version of EPPA, EPPA version 4. In comparison with EPPA3, it includes greater regional and sectoral detail, a wider range of advanced energy supply technologies, improved capability to represent a variety of different and more realistic climate policies, and enhanced treatment of physical stocks and flows of energy, emissions, and land use to facilitate linkage with the earth system components of the IGSM. Reconsideration of important parameters and assumptions led to some revisions in reference projections of GDP and greenhouse gas emissions. In EPPA4 the global economy grows by 12.5 times from 2000 to 2100 (2.5% per year) compared with an increase of 10.7 times (2.4% per year) in EPPA3. This is one of the important revisions that led to an increase in CO2 emissions to 25.7 GtC in 2100, up from 23 GtC in 2100 projected by EPPA3. There is considerable uncertainty in such projections because of uncertainty in various driving forces. To illustrate this uncertainty we consider scenarios where the global GDP grows 0.5% faster (slower) than the reference rate, and these scenarios result in CO2 emissions in 2100 of 34 (17) GtC. A sample greenhouse gas policy scenario that puts the world economy on a path toward stabilization of atmospheric CO2 at 550 ppmv is also simulated to illustrate the response of EPPA4 to a policy constraint. Abstract in HTML and technical report in PDF available on the Massachusetts Institute of Technology Joint Program on the Science and Policy of Global Change website (http://mit.edu/globalchange/www/).

MIT Integrated Global System Model (IGSM) Version 2: Model Description and Baseline Evaluation

2005-07-01T00:00:00Z

MIT Integrated Global System Model (IGSM) Version 2: Model Description and Baseline Evaluation Sokolov, Andrei P.; Schlosser, C. Adam.; Dutkiewicz, Stephanie.; Paltsev, Sergey.; Kicklighter, David W.; Jacoby, Henry D.; Prinn, Ronald G.; Forest, Chris Eliot.; Reilly, John M.; Wang, Chien.; Felzer, Benjamin Seth.; Sarofim, Marcus C.; Scott, Jeffery.; Stone, Peter H.; Melillo, Jerry M.; Cohen, Jason B. The MIT Integrated Global System Model (IGSM) is designed for analyzing the global environmental changes that may result from anthropogenic causes, quantifying the uncertainties associated with the projected changes, and assessing the costs and environmental effectiveness of proposed policies to mitigate climate risk. This report documents Version 2 of the IGSM, which like the previous version, includes an economic model for analysis of greenhouse gas and aerosol precursor emissions and mitigation proposals, a coupled atmosphere-ocean-land surface model with interactive chemistry, and models of natural ecosystems. In this global framework the outputs of the combined anthropogenic and natural emissions models provide the driving forces for the coupled atmospheric chemistry and climate models. Climate model outputs then drive a terrestrial model predicting water and energy budgets, CO2, CH4, and N2O fluxes, and soil composition, which feed back to the coupled climate/chemistry model. The first version of the integrated framework (which we will term IGSM1) is described in Prinn et al. (1999) and in publications and Joint Program Reports and Technical Notes provided on the Program’s website (http://mit.edu/globalchange/). Subsequently, upgrades of component model capabilities have been achieved, allowing more comprehensive and realistic studies of global change. Highlights of these improvements include: a substantially improved economics model, needed to provide emissions projections and to assess an increasingly complex policy environment; a new global terrestrial model comprised of state-of-the-art biogeophysical, ecological and natural biogeochemical flux components, which provides an improved capacity to study consequences of hydrologic and ecologic change; the addition of a three-dimensional ocean representation, replacing the previous two-dimensional model, which allows examination of the global thermohaline circulation and its associated climate change impacts; the addition of an explicit oceanic carbon cycle including the impact of the biological pump; the addition of a new urban air pollution model enabling better treatments of human health and climate impacts; and the addition of greater flexibility for study of terrestrial ecosystem and urban pollution effects. This report documents the essential features of the new IGSM structure. Abstract in HTML and technical report in PDF available on the Massachusetts Institute of Technology Joint Program on the Science and Policy of Global Change website (http://mit.edu/globalchange/www/).

Simulating the Spatial Distribution of Population and Emissions to 2100

2005-05-01T00:00:00Z

Simulating the Spatial Distribution of Population and Emissions to 2100 Asadoorian, Malcolm O. Urbanization and economic development have important implications for many environmental processes including global climate change. Although there is evidence that urbanization depends endogenously on economic variables, long-term forecasts of the spatial distribution of population are often made exogenously and independent of economic conditions. A beta distribution for individual countries/regions is estimated to describe the geographical distribution of population using a 1° x 1° latitude-longitude global population data set. Cross-sectional country/regional data are then used to estimate an empirical relationship between parameters of the beta distribution and macroeconomic variables as they vary among countries/regions. This conditional beta distribution allows the simulation of a changing distribution of population, including the growth of urban areas, driven by economic forecasts until the year 2100. Abstract in HTML and technical report in PDF available on the Massachusetts Institute of Technology Joint Program on the Science and Policy of Global Change website (http://mit.edu/globalchange/www/).

A Three-Dimensional Ocean-Seaice-Carbon Cycle Model and its Coupling to a Two-Dimensional Atmospheric Model: Uses in Climate Change Studies

2005-05-01T00:00:00Z

A Three-Dimensional Ocean-Seaice-Carbon Cycle Model and its Coupling to a Two-Dimensional Atmospheric Model: Uses in Climate Change Studies Dutkiewicz, Stephanie.; Sokolov, Andrei P.; Scott, Jeffery.; Stone, Peter H. We describe the coupling of a three-dimensional ocean circulation model, with explicit thermodynamic seaice and ocean carbon cycle representations, to a two-dimensional atmospheric/land model. This coupled system has been developed as an efficient and flexible tool with which to investigate future climate change scenarios. The setup is sufficiently fast for large ensemble simulations that address uncertainties in future climate modeling. However, the ocean component is detailed enough to provide a tool for looking at the mechanisms and feedbacks that are essential for understanding the future changes in the ocean system. Here we show results from a single example simulation: a spin-up to pre-industrial steady state, changes to ocean physical and biogeochemical states for the 20th century (where changes in greenhouse gases and aerosol concentrations are taken from observations) and predictions of further changes for the 21st century in response to increased greenhouse gas and aerosol emissions. We plan, in future studies to use this model to investigate processes important to the heat uptake of the oceans, changes to the ocean circulation and mechanisms of carbon uptake and how these will change in future climate scenarios. Abstract in HTML and technical report in PDF available on the Massachusetts Institute of Technology Joint Program on the Science and Policy of Global Change website (http://mit.edu/globalchange/www/).

Climate Change Taxes and Energy Efficiency in Japan

2005-05-01T00:00:00Z

Climate Change Taxes and Energy Efficiency in Japan Kasahara, Satoru.; Paltsev, Sergey.; Reilly, John M.; Jacoby, Henry D.; Ellerman, A. Denny. In 2003 Japan proposed a Climate Change Tax to reduce its CO2 emissions to the level required by the Kyoto Protocol. If implemented, the tax would be levied on fossil fuel use and the revenue distributed to several sectors of the economy to encourage the purchase of energy efficient equipment. Analysis using the MIT Emissions Prediction and Policy Analysis (EPPA) model shows that this policy is unlikely to bring Japan into compliance with its Kyoto target unless the subsidy encourages improvement in energy intensity well beyond Japan’s recent historical experience. Similar demand-management programs in the U.S., where there has been extensive experience, have not been nearly as effective as they would need to be to achieve energy efficiency goals of the proposal. The Climate Change Tax proposal also calls for restricting Japan’s participation in the international emission trading. We consider the economic implications of limits on emissions trading and find that they are substantial. Full utilization of international emission trading by Japan reduces the carbon price, welfare loss, and impact on its energy-intensive exports substantially. The welfare loss with full emissions trading is one-sixth that when Japan meets its target though domestic actions only, but Japan can achieve substantial savings even under cases where, for example, the full amount of the Russian allowance is not available in international markets. Abstract in HTML and technical report in PDF available on the Massachusetts Institute of Technology Joint Program on the Science and Policy of Global Change website (http://mit.edu/globalchange/www/).

What Should the Government Do To Encourage Technical Change in the Energy Sector?

2005-05-01T00:00:00Z

What Should the Government Do To Encourage Technical Change in the Energy Sector? Deutch, John M. Government support of innovation—both technology creation and technology demonstration—is desirable to encourage private investors to adopt new technology. In this paper, I review the government role in encouraging technology innovation and the success of the U.S. Department of Energy (DOE) and its predecessor agencies in advancing technology in the energy sector. The DOE has had better success in the first stage of innovation (sponsoring R&D to create new technology options) than in the second stage (demonstrating technologies with the objective of encouraging adoption by the private sector). I argue that the DOE does not have the expertise, policy instruments, or contracting flexibility to successfully manage technology demonstration, and that consideration should be given to establishing a new mechanism for this purpose. The ill-fated 1980 Synthetic Fuels Corporation offers an interesting model for such a mechanism. Abstract in HTML and technical report in PDF available on the Massachusetts Institute of Technology Joint Program on the Science and Policy of Global Change website (http://mit.edu/globalchange/www/).

Does Model Sensitivity to Changes in CO2 Provide a Measure of Sensitivity to the Forcing of Different Nature?

2005-03-01T00:00:00Z

Does Model Sensitivity to Changes in CO2 Provide a Measure of Sensitivity to the Forcing of Different Nature? Sokolov, Andrei P. Simulation of both the climate of the 20th century and of possible future climate change requires taking into account numerous forcings of different nature. Climate sensitivities of existing general circulation models, defined as the equilibrium surface warming due to increase in atmospheric CO2 concentrations, vary over a rather wide range. A large number of simulations with the MIT climate model of intermediate complexity with forcings of different nature have been carried out to study to what extent sensitivity to changes in CO2 concentration represent sensitivities to other forcings. Sensitivity of the MIT model can be changed by changing the strength of the cloud feedback. Simulations with the versions of the model with different sensitivities show that the sensitivity to changes in CO2 concentration provides a reasonably good measure of the model sensitivity to other forcings with similar vertical stratifications. However the range of models’ responses to the forcings leading to the cooling of the surface is narrower than the range of models’ responses to the forcings leading to warming. This is explained by the cloud feedback being less efficient in the case of increasing sea ice extent and snow cover. The range of models’ responses to the forcings with different vertical structure, such as increase in black carbon concentration, is also smaller than that for changes in CO2 concentration. Abstract in HTML and technical report in PDF available on the Massachusetts Institute of Technology Joint Program on the Science and Policy of Global Change website (http://mit.edu/globalchange/www/).

Effects of Air Pollution Control on Climate

2005-01-01T00:00:00Z

Effects of Air Pollution Control on Climate Prinn, Ronald G.; Reilly, John M.; Sarofim, Marcus C.; Wang, Chien.; Felzer, Benjamin Seth. Urban air pollution and climate are closely connected due to shared generating processes (e.g., combustion) for emissions of the driving gases and aerosols. They are also connected because the atmospheric lifecycles of common air pollutants such as CO, NOx and VOCs, and of the climatically important methane gas (CH4) and sulfate aerosols, both involve the fast photochemistry of the hydroxyl free radical (OH). Thus policies designed to address air pollution may impact climate and vice versa. We present calculations using a model coupling economics, atmospheric chemistry, climate and ecosystems to illustrate some effects of air pollution policy alone on global warming. We consider caps on emissions of NOx, CO, volatile organic carbon, and SOx both individually and combined in two ways. These caps can lower ozone causing less warming, lower sulfate aerosols yielding more warming, lower OH and thus increase CH4 giving more warming, and finally, allow more carbon uptake by ecosystems leading to less warming. Overall, these effects significantly offset each other suggesting that air pollution policy has a relatively small net effect on the global mean surface temperature and sea level rise. However, our study does not account for the effects of air pollution policies on overall demand for fossil fuels and on the choice of fuels (coal, oil, gas), nor have we considered the effects of caps on black carbon or organic carbon aerosols on climate. These effects, if included, could lead to more substantial impacts of capping pollutant emissions on global temperature and sea level than concluded here. Caps on aerosols in general could also yield impacts on other important aspects of climate beyond those addressed here, such as the regional patterns of cloudiness and precipitation. Abstract in HTML and technical report in PDF available on the Massachusetts Institute of Technology Joint Program on the Science and Policy of Global Change website (http://mit.edu/globalchange/www/).

Modeling the Transport Sector: The Role of Existing Fuel Taxes in Climate Policy

2004-11-01T00:00:00Z

Modeling the Transport Sector: The Role of Existing Fuel Taxes in Climate Policy Paltsev, Sergey.; Jacoby, Henry D.; Reilly, John M.; Viguier, Laurent L. Existing fuel taxes play a major role in determining the welfare effects of exempting the transportation sector from measures to control greenhouse gases. To study this phenomenon we modify the MIT Emissions Prediction and Policy Analysis (EPPA) model to disaggregate the household transportation sector. This improvement requires an extension of the GTAP data set that underlies the model. The revised and extended facility is then used to compare economic costs of cap-and-trade systems differentiated by sector, focusing on two regions: the USA where the fuel taxes are low, and Europe where the fuel taxes are high. We find that the interplay between carbon policies and pre-existing taxes leads to different results in these regions: in the USA exemption of transport from such a system would increase the welfare cost of achieving a national emissions target, while in Europe such exemptions will correct pre-existing distortions and reduce the cost. Abstract in HTML and technical report in PDF available on the Massachusetts Institute of Technology Joint Program on the Science and Policy of Global Change website (http://mit.edu/globalchange/www/).

Explaining Long-Run Changes in the Energy Intensity of the U.S. Economy

2004-09-01T00:00:00Z

Explaining Long-Run Changes in the Energy Intensity of the U.S. Economy Sue Wing, Ian.; Eckaus, Richard S. Recent events have revived interest in explaining the long-run changes in the energy intensity of the U.S. economy. We use a KLEM dataset for 35 industries over 39 years to decompose changes in the aggregate energy-GDP ratio into shifts in sectoral composition (structural change) and adjustments in the energy demand of individual industries (intensity change). We find that although structural change offsets a rise in sectoral energy intensities from 1960 until the mid-1970s, after 1980 the change in the industrial mix has little impact and the average sectoral energy intensity experiences decline. Then, we use these data to econometrically estimate the influence on within-industry changes in energy intensity of price-induced substitution of variable inputs, shifts in the composition of capital and embodied and disembodied technical progress. Our results suggest that innovations embodied in information technology and electrical equipment capital stocks played a key role in energy intensityâ€™s long-run decline. Abstract in HTML and technical report in PDF available on the Massachusetts Institute of Technology Joint Program on the Science and Policy of Global Change website (http://mit.edu/globalchange/www/).

Future United States Energy Security Concerns

2004-09-01T00:00:00Z

Future United States Energy Security Concerns Deutch, John M. Without energy, the economy can neither function nor grow. However, for at least the next half-century, the U.S. will not have an inexhaustible supply of inexpensive, clean energy. Dependence on energy imports, vulnerability to energy supply disruption, and issues of proliferation of nuclear material are cause for special concern. This paper addresses the geopolitical realities of and connections between energy and security, especially how the energy security issues that we face in the future differ from those we faced in the past. Abstract in HTML and technical report in PDF available on the Massachusetts Institute of Technology Joint Program on the Science and Policy of Global Change website (http://mit.edu/globalchange/www/).

The Role of Non-CO2 Greenhouse Gases in Climate Policy: Analysis Using the MIT IGSM

2004-08-01T00:00:00Z

The Role of Non-CO2 Greenhouse Gases in Climate Policy: Analysis Using the MIT IGSM Reilly, John M.; Sarofim, Marcus C.; Paltsev, Sergey.; Prinn, Ronald G. First steps toward a broad climate agreement, such as the Kyoto Protocol, have focused attention on agreement with less than global geographic coverage. We consider instead a policy that is less comprehensive in term of greenhouse gases (GHGs), including only the non-CO2 GHGs, but is geographically comprehensive. Abating non-CO2 GHGs may be seen as less of a threat to economic development and therefore it may be possible to involve developing countries in such a policy who have thus far resisted limits on CO2 emissions. The policy we consider involves a GHG price of about $15 per ton carbon-equivalent (tce) levied only on the non-CO2 GHGs and held at that level through the century. We estimate that such a policy would reduce the global mean surface temperature in 2100 by about 0.57 degrees C; application of this policy to methane alone would achieve a reduction of 0.3 to 0.4 degrees C. We estimate the Kyoto Protocol in its current form would achieve a 0.30 degrees C reduction in 2100 if all Annex B Parties except the US maintained it as is through the century. Furthermore, we estimate the costs of the non-CO2 policies to be a small fraction of the Kyoto restriction. Whether as a next step to expand the Kyoto Protocol, or as a separate initiative running parallel to it, the world could make substantial progress on limiting climate change by pursuing an agreement to abate the non-CO2 GHGs. The results suggest that it would be useful to proceed on global abatement of non-CO2 GHGs so that lack of progress on negotiations to limit CO2 does not allow these abatement opportunities to slip away. Abstract in HTML and technical report in PDF available on the Massachusetts Institute of Technology Joint Program on the Science and Policy of Global Change website (http://mit.edu/globalchange/www/).

Air Pollution Health Effects: Toward an Integrated Assessment

2004-07-01T00:00:00Z

Air Pollution Health Effects: Toward an Integrated Assessment Yang, Trent.; Reilly, John M.; Paltsev, Sergey. Scientists and policy makers have become increasingly aware of the need to jointly study climate change and air pollution because of the interactions among policy measures and in the atmospheric chemistry that creates the constituents of smog and affects the lifetimes of important greenhouse gases such as methane. Tropospheric ozone and aerosols, recognized constituents of air pollution, have important effects on the radiative balance of the atmosphere. Existing methods for estimating the economic implications of environmental damage do not provide an immediate approach to assess the economic and policy interactions. Towards that end, we develop a methodology for integrating the health effects from exposure to air pollution into the MIT Emissions Prediction and Policy Analysis (EPPA) model, a computable general equilibrium economic model of the economy that has been widely used to study climate change policy. The approach incorporates market and non-market effects of air pollution on human health, and is readily applicable to other environmental damages including those from climate change. The estimate of economic damages depends, of course, on the validity of the underlying epidemiological relationships and direct estimates of the consequences of health effects such as lost work and non-work time and increased medical expenses. We apply the model to the US for the historical period 1970 to 2000, and reevaluate estimates of the benefits of US air pollution regulations originally made by the US Environmental Protection Agency. We also estimate the economic burden of uncontrolled levels of air pollution over that period. Our estimated benefits of regulation are somewhat lower than the original EPA estimates, and we trace that result to our development of a stock model of pollutant exposure that predicts that the benefits from reduced chronic air pollution exposure will only be gradually realized. As modeled, only population cohorts born under lower air pollution levels fully realize the benefits. While other assumptions about the nature of health effects of chronic exposure are possible, some version of a stock model of this type is needed to accurately estimate the timing of benefits of reduced pollution. Abstract in HTML and technical report in PDF available on the Massachusetts Institute of Technology Joint Program on the Science and Policy of Global Change website (http://mit.edu/globalchange/www/).

The Cost of Kyoto Protocol Targets: The Case of Japan

2004-07-01T00:00:00Z

The Cost of Kyoto Protocol Targets: The Case of Japan Paltsev, Sergey.; Reilly, John M.; Jacoby, Henry D.; Tay, Kok Hou. This paper applies the MIT Emissions Prediction and Policy Analysis (EPPA) model to analysis of the cost of the Kyoto Protocol targets, with a special focus on Japan. The analysis demonstrates the implications of the use of different measures of cost, and explains the apparent paradox that the relative carbon price among Kyoto parties may not be an accurate measure of their relative welfare costs. Attention is given to the role of relative emissions intensity and various distortions, in the form of fuel and other taxes, in determining the burden of a climate policy. Also, effects of climate policy on welfare through an influence on the terms of trade are explored. We consider the cases of the EU, Japan, and Canada, each meeting their Kyoto targets, and the US meeting the Bush Administration’s intensity target. For a country with a low emissions intensity as in Japan, the absolute reduction in tons is small relative to the macroeconomy, and this reduces its welfare loss as a share of total national welfare. Low emissions intensity (high energy efficiency) also means the economy has few options to reduce emissions still further, resulting in a higher carbon price. Energy efficiency thus pushes in both directions, lowering the number tons that need to be reduced but raising the direct cost per ton. But other factors also are important in explaining costs differences. Existing fuel taxes are very high in Japan and Europe, increasing the economic cost of a greenhouse gas emissions reduction policy. For these regions, the extra cost due to these distortions is several times the direct cost of the emissions mitigation policy itself. In contrast, fuels taxes are low in the US and relatively low in Canada. The US, EU, and Japan gain somewhat from reductions in world prices of oil and other fuels because they are net importers. Canada, in contrast, is a significant net energy exporter, and its policy costs rise considerably because of lost energy export revenue. This effect on Canada is due mostly to implementation of the policy in the other regions rather than to domestic implementation. Canada is also the most emissions intensive of these regions, a factor that contributes to its cost of control. Abstract in HTML and technical report in PDF available on the Massachusetts Institute of Technology Joint Program on the Science and Policy of Global Change website (http://mit.edu/globalchange/www/).

Technology and Technical Change in the MIT EPPA Model

2004-07-01T00:00:00Z

Technology and Technical Change in the MIT EPPA Model Jacoby, Henry D.; Reilly, John M.; McFarland, James R.; Paltsev, Sergey. Potential technology change has a strong influence on projections of greenhouse gas emissions and costs of control, and computable general equilibrium (CGE) models are a common device for studying these phenomena. Using the MIT Emissions Prediction and Policy Analysis (EPPA) model as an example, two ways of representing technology in these models are discussed: the sector-level description of production possibilities founded on social accounting matrices and elasticity estimates, and sub-models of specific supply or end-use devices based on engineering-process data. A distinction is made between exogenous and endogenous technical change, and it is shown how, because of model structure and the origin of key parameters, such models naturally include shifts in production process that reflect some degree of endogenous technical change. As a result, the introduction of explicit endogenous relations should be approached with caution, to avoid double counting. Abstract in HTML and technical report in PDF available on the Massachusetts Institute of Technology Joint Program on the Science and Policy of Global Change website (http://mit.edu/globalchange/www/).

Stabilization and Global Climate Policy

2004-07-01T00:00:00Z

Stabilization and Global Climate Policy Sarofim, Marcus C.; Forest, Chris Eliot.; Reiner, David M.; Reilly, John M. Academic and political debates over long-run climate policy often invoke “stabilization” of atmospheric concentrations of greenhouse gases (GHGs), but only rarely are non-CO2 greenhouse gases addressed explicitly. Even though the majority of short-term climate policies propose trading between gases on a global warming potential (GWP) basis, discussions of whether CO2 concentrations should be 450, 550, 650, or perhaps as much as 750 ppm leave unstated whether there should be no additional forcing from other GHGs beyond current levels or whether separate concentration targets should be established for each GHG. Here we use an integrated modeling framework to examine multi-gas stabilization in terms of temperature, economic costs, carbon uptake, and other important consequences. We show that there are significant differences in both costs and climate impacts between different "GWP equivalent" policies and demonstrate the importance of non-CO2 GHG reduction on timescales of up to several centuries. Abstract in HTML and technical report in PDF available on the Massachusetts Institute of Technology Joint Program on the Science and Policy of Global Change website (http://mit.edu/globalchange/www/).

Sensitivity of Climate to Diapycnal Diffusivity: Part I. Equilibrium State; Part II. Global Warming Scenario

2004-05-01T00:00:00Z

Sensitivity of Climate to Diapycnal Diffusivity: Part I. Equilibrium State; Part II. Global Warming Scenario Dalan, Fabio.; Stone, Peter H.; Kamenkovich, Igor V.; Scott, Jeffery.; Sokolov, Andrei P. Part I: The diapycnal diffusivity in the ocean is one of the least known parameters in current climate models. Measurements of this diffusivity are sparse and insufficient for compiling a global map. Inferences from inverse methods and energy budget calculations suggest as much as a factor of 5 difference in the global mean value of the diapycnal diffusivity. Yet, the climate is extremely sensitive to the diapycnal diffusivity. In this paper we study the sensitivity of the current climate to the diapycnal diffusivity using a coupled model with a 3-dimensional global ocean component with idealized geometry. In a subsequent paper we analyze the sensitivity of the climate change to the same parameter. Our results show that, at equilibrium, the strength of the thermohaline circulation in the North Atlantic scales with the 0.44 power of the diapycnal diffusivity, in contrast to the theoretical value of 2/3. On the other hand, the strength of the circulation in the South Pacific scales with the 0.63 power of the diapycnal diffusivity. The implication is that the amount of water upwelling from the deep ocean may be regulated by the diapycnal diffusion in the Indo-Pacific Ocean. The vertical heat balance in the ocean is controlled by: in the downward direction, (i) advection and (ii) diapycnal diffusion; in the upward direction, (iii) isopycnal diffusion and (iv) bolus velocity (GM) advection. The size of the latter three fluxes increases with diapycnal diffusivity, because the thickness of the thermocline also increases with diapycnal diffusivity leading to greater isopycnal slopes at high latitudes, and hence enhanced isopycnal diffusion and GM advection. Thus larger diapycnal diffusion is compensated for by changes in isopycnal diffusion and GM advection. Little change is found for the advective flux because of compensation between downward and upward advection. We present sensitivity results for the hysteresis curve of the thermohaline circulation. The stability of the climate system to slow freshwater perturbations is reduced as a consequence of a smaller diapycnal diffusivity. This result confirms the findings of 2-dimensional climate models. However, contrary to the results of these studies, a common threshold for the shutdown of the thermohaline circulation is not found in our model. Part II: The sensitivity of the transient climate to the diapycnal diffusivity in the ocean is studied for a global warming scenario in which CO2 increases by 1% per year for 75 years. The thermohaline circulation slows down for about 100 years and recovers afterward, for any value of the diapycnal diffusivity. The rates of slowdown and of recovery, as well as the percentage recovery of the circulation at the end of 1000-year integrations, are variable but a direct relation with the diapycnal diffusivity cannot be found. At year 70 (when CO2, has doubled) an increase of the diapycnal diffusivity from 0.1 cm2/s to 1.0 cm2/s leads to a decrease in surface air temperature of about 0.4 K and an increase in sea level rise of about 4 cm The steric height gradient is divided into thermal component and haline component. It appears that, in the first 60 years of simulated global warming, temperature variations dominate the salinity ones in weakly diffusive models, whereas the opposite occurs in strongly diffusive models. The analysis of the vertical heat balance reveals that deep ocean heat uptake is due to reduced upward isopycnal diffusive flux and Gent-McWilliams advective flux. Surface warming, induced by enhanced CO2 in the atmosphere, leads to a reduction of the isopycnal slope which translates into a reduction of the above fluxes. The amount of reduction is directly related to the magnitude of the isopycnal diffusive flux and GM advective flux at equilibrium. These latter fluxes depend on the thickness of the thermocline at equilibrium, hence on the diapycnal diffusion. Thus, the increase of deep-ocean heat uptake with diapycnal diffusivity is an indirect effect that the latter parameter has on the isopycnal diffusion and GM advection Abstract in HTML and technical report in PDF available on the Massachusetts Institute of Technology Joint Program on the Science and Policy of Global Change website (http://mit.edu/globalchange/www/).

Methane Fluxes Between Terrestrial Ecosystems and the Atmosphere at Northern High Latitudes During the Past Century: A retrospective analysis with a process-based biogeochemistry model

2004-03-01T00:00:00Z

Methane Fluxes Between Terrestrial Ecosystems and the Atmosphere at Northern High Latitudes During the Past Century: A retrospective analysis with a process-based biogeochemistry model Zhuang, Qianlai.; Melillo, Jerry M.; Kicklighter, David W.; Prinn, Ronald G.; McGuire, A. David.; Steudler, Paul A.; Felzer, Benjamin Seth.; Hu, Shaomin. We develop and use a new version of the Terrestrial Ecosystem Model (TEM) to study how rates of methane (CH4) emissions and consumption in high-latitude soils of the Northern Hemisphere have changed over the past century in response to observed changes in the region’s climate. We estimate that the net emissions of CH4 (emissions minus consumption) from these soils have increased by an average 0.08 Tg CH4 per year during the 20th century. Our estimate of the annual net emission rate at the end of the century for the region is 51 Tg CH4 per year. Russia, Canada, and Alaska are the major CH4 regional sources to the atmosphere; responsible for 64%, 11%, and 7% of these net emissions, respectively. Our simulations indicate that large inter-annual variability in net CH4 emissions occurred over the last century. If CH4 emissions from the soils of the pan-Arctic region respond to future climate changes as our simulations suggest they have responded to observed climate changes over the 20th century, a large increase in high latitude CH4 emissions is likely and could lead to a major positive feedback to the climate system. Abstract in HTML and technical report in PDF available on the Massachusetts Institute of Technology Joint Program on the Science and Policy of Global Change website (http://mit.edu/globalchange/www/).

Informing Climate Policy Given Incommensurable Benefits Estimates

2004-02-01T00:00:00Z

Informing Climate Policy Given Incommensurable Benefits Estimates Jacoby, Henry D. The determination of long-term goals for climate policy, or of near-term mitigation effort, requires a shared conception among nations of what is at stake. Unfortunately, because of different attitudes to risk, problems of valuing non-market effects, and disagreements about aggregation across rich and poor nations, no single benefit measure is possible that can provide commonly accepted basis for judgment. In response to this circumstance, a portfolio of estimates is recommended, including global variables that can be represented in probabilistic terms, regional impacts expressed in natural units, and integrated monetary valuation. Development of such a portfolio is a research task, and the needed program of work suggested. Abstract in HTML and technical report in PDF available on the Massachusetts Institute of Technology Joint Program on the Science and Policy of Global Change website (http://mit.edu/globalchange/www/).

Climate Prediction: The Limits of Ocean Models

2004-02-01T00:00:00Z

Climate Prediction: The Limits of Ocean Models Stone, Peter H. We identify three major areas of ignorance which limit predictability in current ocean GCMs. One is the very crude representation of subgrid-scale mixing processes. These processes are parameterized with coefficients whose values and variations in space and time are poorly known. A second problem derives from the fact that ocean models generally contain multiple equilibria and bifurcations, but there is no agreement as to where the current ocean sits with respect to the bifurcations. A third problem arises from the fact that ocean circulations are highly nonlinear, but only weakly dissipative, and therefore are potentially chaotic. The few studies that have looked at this kind of behavior have not answered fundamental questions, such as what are the major sources of error growth in model projections, and how large is the chaotic behavior relative to realistic changes in climate forcings. Advances in computers will help alleviate some of these problems, for example by making it more practical to explore to what extent the evolution of the oceans is chaotic. However models will have to rely on parameterizations of key small-scale processes such as diapycnal mixing for a long time. To make more immediate progress here requires the development of physically based prognostic parameterizations and coupling the mixing to its energy sources. Another possibly fruitful area of investigation is the use of paleoclimate data on changes in the ocean circulation to constrain more tightly the stability characteristics of the ocean circulation. Abstract in HTML and technical report in PDF available on the Massachusetts Institute of Technology Joint Program on the Science and Policy of Global Change website (http://mit.edu/globalchange/www/).

Analysis of Strategies of Companies under Carbon Constraint: Relationship between Profit Structure of Companies and Carbon/Fuel Price Uncertainty

2004-01-01T00:00:00Z

Analysis of Strategies of Companies under Carbon Constraint: Relationship between Profit Structure of Companies and Carbon/Fuel Price Uncertainty Hashimoto, Susumu This paper examines the relationship between future carbon prices and the expected profit of companies by case studies with model companies. As the future carbon price will vary significantly in accordance with the political and economic situation, a specified probability density profile for the carbon price in the future has been assumed in this paper and the expected profits of the model company have been calculated on the basis of this profile. A power company has been selected as the model company representing a typical instance of a large-scale emitter of CO2. In the case of a single-fuel using company, it has been established that the influence on corporate profits can be assessed quantitatively by determining the profit break-even line with the carbon price as the parameter using the company’s carbon emission intensity and its operating profit per unit of production output. For multi-fueled companies, it is shown that the future optimum fuel mix is determined not only by the carbon price but also by the operating profit ratio for the fuels concerned. These studies have thus confirmed that corporate profits are governed by the ratio of the operating profit levels achieved per unit of production output for the different fuels and the carbon price. Abstract in HTML and technical report in PDF available on the Massachusetts Institute of Technology Joint Program on the Science and Policy of Global Change website (http://mit.edu/globalchange/www/).

A Process-based Analysis of Methane Exchanges Between Alaskan Terrestrial Ecosystems and the Atmosphere

2003-11-01T00:00:00Z

A Process-based Analysis of Methane Exchanges Between Alaskan Terrestrial Ecosystems and the Atmosphere Zhuang, Qianlai.; Melillo, Jerry M.; Kicklighter, David W.; Prinn, Ronald G.; McGuire, A. David.; Steudler, Paul A.; Felzer, Benjamin Seth.; Hu, Shaomin. We developed and used a new version of the Terrestrial Ecosystem Model (TEM) to study how rates of methane (CH4) emissions and consumption in Alaskan soils have changed over the past century in response to observed changes in the state’s climate and are likely to change with projected climate changes over this century. We estimate that the current net emissions of CH4 (emissions minus consumption) from Alaskan soils are about 3 Tg CH4 per year. We project that net CH4 emissions will almost double by the end of the century in response to high-latitude warming and associated climate changes. If CH4 emissions from soils of the pan-Arctic region respond to climate changes in the way we project for the Alaskan soils, the net increase in high latitude CH4 emissions could lead to a major positive feedback to the climate system. Abstract in HTML and technical report in PDF available on the Massachusetts Institute of Technology Joint Program on the Science and Policy of Global Change website (http://mit.edu/globalchange/www/).

Past and Future Effects of Ozone on Net Primary Production and Carbon Sequestration Using a Global Biogeochemical Model

2003-10-01T00:00:00Z

Past and Future Effects of Ozone on Net Primary Production and Carbon Sequestration Using a Global Biogeochemical Model Felzer, Benjamin Seth.; Reilly, John M.; Melillo, Jerry M.; Kicklighter, David W.; Wang, Chien.; Prinn, Ronald G.; Sarofim, Marcus C.; Zhuang, Qianlai. Exposure of plants to ozone inhibits photosynthesis and therefore reduces vegetation production and carbon sequestration. Simulations with the Terrestrial Ecosystem Model (TEM) for the historical period (1860-1995) show the largest damages occur in the eastern U.S., Europe, and eastern China, with reductions in Net Primary Production (NPP) of over 70% for some locations. Scenarios through the year 2100 using the MIT Integrated Global Systems Model (IGSM) show potentially greater negative effects in the future. In the worst-case scenario, the current land carbon sink in China could become a carbon source. Reduced crop yields resulting from ozone damage are potentially large but can be mitigated by controlling emissions of ozone precursors. Failure to consider ozone damages to vegetation would by itself raise the costs over the next century of stabilizing atmospheric concentrations of CO2 by 3 to 18%. But, climate policy would also reduce ozone precursor emissions, and ozone, and these additional benefits are estimated to be between 4 and 21% of the cost of the climate policy. Tropospheric ozone effects on terrestrial ecosystems thus produce a surprisingly large feedback in estimating climate policy costs that, heretofore, has not been included in cost estimates. Abstract in HTML and technical report in PDF available on the Massachusetts Institute of Technology Joint Program on the Science and Policy of Global Change website (http://mit.edu/globalchange/www/).

Induced technical change and the cost of climate policy

2003-09-01T00:00:00Z

Induced technical change and the cost of climate policy Sue Wing, Ian. This paper investigates the potential for a carbon tax to induce R&D, and for the consequent induced technical change (ITC) to lower the macroeconomic cost of abating carbon emissions. ITC is modelled within a general equilibrium simulation of the U.S. economy by the effects of emissions restrictions on the level and composition of aggregate R&D, the accumulation of the stock of knowledge, and the industry-level reallocation and substitution of intangible services derived therefrom. Contrary to other authors, I find that ITC's impact is large, positive and dominated by the latter "substitution effect," which mitigates most of the deadweight loss of the tax. Abstract in HTML and technical report in PDF available on the Massachusetts Institute of Technology Joint Program on the Science and Policy of Global Change website (http://mit.edu/globalchange/www/).

Uncertainty in climate change policy analysis

1994-12-01T00:00:00Z

Uncertainty in climate change policy analysis Achieving agreement about whether and how to control greenhouse gas emissions would be difficult enough even if the consequences were fully known. Unfortunately, choices must be made in the face of great uncertainty, about both likely climate effects and the costs of control. Because several of the greenhouse gases have residence times of decades to centuries, any economic and environmental consequences are for practical purposes irreversible on those time scales. On the other hand, the commitment of resources to emissions control also has an irreversible aspect: investment foregone leaves a permanent legacy of reduced human welfare. Neither of the extreme positions, to take urgent action now or do nothing awaiting firm evidence, is a constructive response to the climate threat. Responsible treatment of this issue leads to a difficult position somewhere in between. Includes bibliographical references (p. 32-34).; Abstract in HTML and technical report in HTML and PDF available on the Massachusetts Institute of Technology Joint Program on the Science and Policy of Global Change website (http://mit.edu/globalchange/www/).

Description and validation of the MIT version of GISS 2-D model

1995-06-01T00:00:00Z

Description and validation of the MIT version of GISS 2-D model A significant number of long-term climate change simulations are to be carried out in the Integrated Framework of the MIT Global Change Joint Program. Since Global Circulation Models (GCMs) require an enormous amount of computer time, the two-dimensional statistical-dynamic model developed by Stone and Yao was chosen to be used for the initial stage of the Joint Program. At MIT, the model has been modified to make it more suitable for the purposes of the Joint Program, including developing a new scheme for a surface flux calculation. A number of simulations with the modified version of the model have been performed in which a few schemes for cloud and ocean heat transport calculation have been tested. Comparisons of the results of the present climate simulations with observational data show that the model reasonably reproduces main features of zonally averaged atmospheric circulation. A climate sensitivity produced by the model coupled with a mixed layer ocean model in response to the doubling of the atmospheric CO2 concentration lies in the range of the results obtained with GCMs. The results of the simulations with a gradual increase of the greenhouse gas concentrations in the atmosphere, in which diffusion of heat into the deep ocean was taken into account, are also similar to those obtained in the analogous simulations with GCMs. As a whole, presented results demonstrate that the modified version of the two-dimensional model can be successfully used for climate change predictions in the Integrated Framework of the Joint Program. Includes bibliographical references (p. 13-14).; Abstract in HTML and technical report in HTML and PDF available on the Massachusetts Institute of Technology Joint Program on the Science and Policy of Global Change website (http://mit.edu/globalchange/www/).

Responses of primary production and total carbon storage to changes in climate and atmospheric CO₂ concentration

1995-10-01T00:00:00Z

Responses of primary production and total carbon storage to changes in climate and atmospheric CO₂ concentration The authors used the terrestrial ecosystem model (TEM, version 4.0) to estimate global responses of annual net primary production (NPP) and total carbon storage to changes in climate and atmospheric CO2, driven by the climate outputs from the 2-dimensional MIT L-O climate model and the 3-dimensional GISS and GFDL-q atmospheric general circulation models (GCMs). For contemporary climate with 315 ppmv CO2, TEM estimates that global NPP is 47.9 PgC/yr and global total carbon storage is 1658 PgC: 908 PgC of vegetation carbon and 750 PgC of reactive soil organic carbon. For climate change associated with a doubling of radiative forcing and an atmospheric level of 522 ppmv CO2, the responses of global NPP are +17.8% for the MIT L-O climate, +18.5% for the GFDL-q climate and +20.6% for the GISS climate. The responses of global total carbon storage are +6.9% for the MIT L-O climate, +8.3% for GFDL-q climate and +8.7% for the GISS climate. Among the three climate change predictions, the changes in latitudinal distributions of cumulative NPP and total carbon storage along 0.5o latitudinal bands vary slightly, except in high latitudes. There are generally minor differences in cumulative NPP and total carbon storage for most of the 18 biomes, except for the responses of total carbon storage in boreal biomes for the 2-D MIT L-O climate change. The results demonstrate that the linkage between the TEM and the 2-D climate model is useful for impact assessment and uncertainty analysis within an integrated assessment framework at the scales of the globe, economic regions and biomes, given the compromise between computational efficiency in the 2-D climate model and more detailed spatial representation of climate fields in 3-D GCMs. Includes bibliographical references (p. 13-16).; Abstract in HTML and technical report in HTML and PDF available on the Massachusetts Institute of Technology Joint Program on the Science and Policy of Global Change website (http://mit.edu/globalchange/www/).

Application of the probabilistic collocation method for an uncertainty analysis of a simple ocean model

1996-01-01T00:00:00Z

Application of the probabilistic collocation method for an uncertainty analysis of a simple ocean model This paper presents the probabilistic collocation method as a computationally efficient method for performing uncertainty analysis on large complex models such as those used in global climate change research. The collocation method is explained, and then the results of its application to a box model of ocean thermohaline circulation are presented. A comparison of the results of the collocation method with a traditional Monte Carlo simulation show that the collocation method gives a better approximation for the probability density function of the model's response with less than 20 model runs as compared with a Monte Carlo simulation of 5000 model runs. Includes bibliographical references (p. 21).; Abstract in HTML and technical report in HTML and PDF available on the Massachusetts Institute of Technology Joint Program on the Science and Policy of Global Change website (http://mit.edu/globalchange/www/).

World energy consumption and carbon dioxide emissions : 1950-2050

1996-04-01T00:00:00Z

World energy consumption and carbon dioxide emissions : 1950-2050 Emissions of carbon dioxide from combustion of fossil fuels, which may contribute to long-term climate change, are projected through 2050 using reduced form models estimated with national-level panel data for the period 1950-1990. We employ a flexible form for income effects, along with fixed time and country effects, and we handle forecast uncertainty explicitly. We find an "inverse-U" relation with a within-sample peak between carbon dioxide emissions (and energy use) per capita and per captia income. Using the income and population growth assumptions of the Intergovernmental Panel on Climate Change (IPCC), we obtain projections significantly and substantially above those of the IPCC. Includes bibliographical references (p. 25-27).; Abstract in HTML and technical report in HTML and PDF available on the Massachusetts Institute of Technology Joint Program on the Science and Policy of Global Change website (http://mit.edu/globalchange/www/).

Relative role of changes in CO₂ and climate to equilibrium responses of net primary production and carbon storage of the terrestrial biosphere

1996-06-01T00:00:00Z

Relative role of changes in CO₂ and climate to equilibrium responses of net primary production and carbon storage of the terrestrial biosphere In a partial factorial model experiment, we used the Terrestrial Ecosystem Model (TEM, version 4.0) to assess the relative roles of changes in CO2, temperature, precipitation and cloudiness in equilibrium responses of primary production and carbon storage. In the experiment, we used two levels of atmospheric CO2 concentration (315 and 522 ppmv CO2), contemporary climate and changes in temperature, precipitation and cloudiness as estimated by a 3-dimensional atmospheric general circulation model (Geophysical Fluid Dynamic Laboratory-GFDL) and a 2-dimensional climate model (Land-Ocean climate model at Massachusetts Institute of Technology) for doubled CO2. The results show that elevated CO2 and projected increases in temperature account for most of the overall equilibrium responses of NPP and carbon storage to changes in climate and CO2, while the projected changes in precipitation and cloudiness contribute least. This is partly attributable to the magnitudes of changes in CO2 and climate variables as projected by the climate models. The results also show that the interactions among changes in CO2 and climate variables play a significant role in the equilibrium responses of NPP and carbon storage to changes in CO2 and climate. Of all the interaction terms, the interaction between a change in CO2 and a change in temperature is the most significant. Includes bibliographical references (p. 21-25).; Abstract in HTML and technical report in HTML and PDF available on the Massachusetts Institute of Technology Joint Program on the Science and Policy of Global Change website (http://mit.edu/globalchange/www/).

CO₂ emissions limits: economic adjustments and the distribution of burdens

1996-07-01T00:00:00Z

CO₂ emissions limits: economic adjustments and the distribution of burdens Policies under consideration within the Climate Convention would impose CO₂ controls on only a subset of nations. A model of economic growth and emissions, coupled to an analysis of the climate system, is used to explore the consequences of a sample proposal of this type. The results show how economic burdens are likely to be distributed among nations, how carbon "leakage" may counteract the reductions attained, and how policy costs may be influenced by emissions trading. We explore the sensitivity of results to uncertainty in key underlying assumptions, including the influence on economic impacts and on the policy contribution to long-term climate goals. Includes bibliographical references (p. 16).; Abstract in HTML and technical report in HTML and PDF available on the Massachusetts Institute of Technology Joint Program on the Science and Policy of Global Change website (http://mit.edu/globalchange/www/).

An issue of permanence: assessing the effectiveness of temporary carbon storage

2002-12-01T00:00:00Z

An issue of permanence: assessing the effectiveness of temporary carbon storage Herzog, Howard J.; Caldeira, Ken.; Reilly, John M. In this paper, we present a method to quantify the effectiveness of carbon mitigation options taking into account the "permanence" of the emissions reduction. While the issue of permanence is most commonly associated with a "leaky" carbon sequestration reservoir, we argue that this is an issue that applies to just about all carbon mitigation options. The appropriate formulation of this problem is to ask 'what is the value of temporary storage?' Valuing temporary storage can be represented as a familiar economic problem, with explicitly stated assumptions about carbon prices and the discount rate. To illustrate the methodology, we calculate the sequestration effectiveness for injecting CO2 at various depths in the ocean. Analysis is performed for three limiting carbon price assumptions: constant carbon prices (assumes constant marginal damages), carbon prices rise at the discount rate (assumes efficient allocation of a cumulative emissions cap without a backstop technology), and carbon prices first rise at the discount rate but become constant after a given time (assumes introduction of a backstop technology). Our results show that the value of relatively deep ocean carbon sequestration can be nearly equivalent to permanent sequestration if marginal damages (i.e., carbon prices) remain constant or if there is a backstop technology that caps the abatement cost in the not too distant future. On the other hand, if climate damages are such as to require a fixed cumulative emissions limit and there is no backstop, then a storage option with even very slow leakage has limited value relative to a permanent storage option. Abstract in HTML and technical report in PDF available on the Massachusetts Institute of Technology Joint Program on the Science and Policy of Global Change website (http://mit.edu/globalchange/www/).

Global warming projections : sensitivity to deep ocean mixing

1996-09-01T00:00:00Z

Global warming projections : sensitivity to deep ocean mixing The climatological impact of increases in greenhouse gas concentrations in the atmosphere, despite being a subject of intensive study in recent years, is still very uncertain. One major uncertainty affecting possible climate change that has not received enough attention is the uncertainty in heat uptake by the deep ocean. We analyze the influence of this process and its uncertainty on climate predictions by means of numerical simulations with a 2-dimensional climate model. In the case of high climate sensitivity, as a result of uncertainty in deep ocean heat uptake, there is more than a factor of two uncertainty in the predicted increase of surface temperature. The corresponding uncertainty in the sea level rise due to thermal expansion is much larger than the uncertainty in the predicted temperature change and is significant even in the case of low climate sensitivity. Includes bibliographical references (p. 3).; Abstract in HTML and technical report in HTML and PDF available on the Massachusetts Institute of Technology Joint Program on the Science and Policy of Global Change website (http://mit.edu/globalchange/www/).

Net primary production of terrestrial ecosystems in China and its equilibrium response to changes in climate and atmospheric CO₂ concentration

1996-10-01T00:00:00Z

Net primary production of terrestrial ecosystems in China and its equilibrium response to changes in climate and atmospheric CO₂ concentration The Terrestrial Ecosystem Model (TEM, version 4.0) was used to estimate net primary production (NPP) in China for contemporary climate and NPP responses to elevated CO₂ and climate changes projected by three atmospheric general circulation models (GCMs): Goddard Institute for Space Studies (GISS), Geophysical Fluid Dynamic Laboratory (GFDL) and Oregon State University (OSU). For contemporary climate at 312.5 ppmv CO₂, TEM estimates that China has an annual NPP of 3,653 TgC/yr (10^12 gC/yr). Temperate broadleaf evergreen forest is the most productive biome and accounts for the largest portion of annual NPP in China. The spatial pattern of NPP is closely correlated to the spatial distributions of precipitation and temperature.Annual NPP of China is sensitive to changes in CO₂ and climate. At the continental scale, annual NPP of China increases by 6.0% (219 TgC/yr) for elevated CO₂ only (519 ppmv CO₂). For climate change with no change in CO₂, the response of annual NPP ranges from a decrease of 1.5% (54.8 TgC/yr) for the GISS climate to an increase of 8.4% (306.9 TgC/yr) for the GFDL-q climate. For climate change at 519 ppmv CO₂, annual NPP of China increases substantially, ranging from 18.7% (683 TgC/yr) for the GISS climate to 23.3% (851 TgC/yr) for the GFDL-q climate. Spatially, the responses of annual NPP to changes in climate and CO₂ vary considerably within a GCM climate. Differences among the three GCM climates used in the study cause large differences in the geographical distribution of NPP responses to projected climate changes. The interaction between elevated CO₂ and climate change plays an important role in the overall response of NPP to climate change at 519 ppmv CO₂. Includes bibliographical references (p. 14-17).; Abstract in HTML and technical report in HTML and PDF available on the Massachusetts Institute of Technology Joint Program on the Science and Policy of Global Change website (http://mit.edu/globalchange/www/).

Greenhouse policy architectures and institutions

1996-11-01T00:00:00Z

Greenhouse policy architectures and institutions This paper discusses the design of efficient environmental policies in general and reviews omissions and shortcomings of the presentation of the economic dimensions of climate change in the Intergovernmental Panel on Climate Change (IPCC) Working Group III's Report: "Climate Change 1995 Economic and Social Dimensions of Climate Change: Contribution of Working Group III to the Second Assessment Report of the Intergovernmental Panel on Climate Change" (Cambridge Univ. Press, Cambridge, UK, 1996). Includes bibliographical references (p. 15-16).; Abstract in HTML and technical report in HTML and PDF available on the Massachusetts Institute of Technology Joint Program on the Science and Policy of Global Change website (http://mit.edu/globalchange/www/).

What does stabilizing greenhouse gas concentrations mean?

1996-11-01T00:00:00Z

What does stabilizing greenhouse gas concentrations mean? The MIT Emissions Prediction and Policy Analysis (EPPA) model is applied to an exploration of the national emissions obligations that would be required to stabilize atmospheric CO2 concentrations at levels now under active discussion. The results indicate that the needed voluntary participation will be difficult to achieve, not least because nations at very different income levels would have to undertake similarly costly emissions restrictions. The need for more attention to the linkage between short-term policy proposals and long-term stabilization goals is highlighted. Includes bibliographical references (p. 16).; Abstract in HTML and technical report in HTML and PDF available on the Massachusetts Institute of Technology Joint Program on the Science and Policy of Global Change website (http://mit.edu/globalchange/www/).

Economic assessment of CO₂ capture and disposal

1996-12-01T00:00:00Z

Economic assessment of CO₂ capture and disposal A multi-sector multi-region general equilibrium model of economic growth and emissions is used to explore the conditions that will determine the market penetration of CO2 capture and disposal technology. Includes bibliographical references (p. 16).; Abstract in HTML and technical report in HTML and PDF available on the Massachusetts Institute of Technology Joint Program on the Science and Policy of Global Change website (http://mit.edu/globalchange/www/).

What drives deforestation in the Brazilian Amazon? : Evidence from satellite and socioeconomic data.

1996-12-01T00:00:00Z

What drives deforestation in the Brazilian Amazon? : Evidence from satellite and socioeconomic data. This paper analyzes the determinants of deforestation in the Brazilian Amazon. From a model of optimal land use, it derives and then estimates a deforestation equation on country-level data for the period 1978 to 1988. The data include a deforestation measure from satellite images, which is a great advance in that it allows improved within-country analysis. Evidence exists that: increased road density in a country leads to more deforestation in that country and in neighboring countries; government-subsidized development projects increase deforestation; greater distance from markets south of the Amazon leads to less deforestation; and better soil quality leads to more deforestation. The results for government provision of credit are mixed across specifications. The population density, although the primary explanatory variable in most previous empirical work, does not have a significant effect when all the variables motivated within the model are included. However, a quadratic specification yields a more robust population result: the first few people entering an empty country have significantly more impact than the same number of people added to a densely populated country. This result suggests the importance of the spatial distribution of population. Abstract in HTML and technical report in HTML and PDF available on the Massachusetts Institute of Technology Joint Program on the Science and Policy of Global Change website (http://mit.edu/globalchange/www/).; Includes bibliographical references.

A flexible climate model for use in integrated assessments

1997-03-01T00:00:00Z

A flexible climate model for use in integrated assessments Includes bibliographical references (p. 14-15).; Abstract in HTML and technical report in HTML and PDF available on the Massachusetts Institute of Technology Joint Program on the Science and Policy of Global Change website (http://mit.edu/globalchange/www/).

Transient climate change and potential croplands of the world in the 21st century

1997-05-01T00:00:00Z

Transient climate change and potential croplands of the world in the 21st century A cropland distribution model, which is based on climate, soil and topography, is applied to estimate the area and spatial distribution of global potential croplands under contemporary climate and to assess the effect of transient climate changes projected by the MIT Integrated Global System Model for assessment of climate change. The area of global potential croplands is about 32.91 x 10^6 km^2 under contemporary climate, and increases substantially over the period of 1977-2100 and differs among the three transient climate change predictions, being about +6.7% (2.20 x 10^6 km^2), +11.5% (3.78 x 10^6 km^2), and +12.5% (4.12 x 10^6 km^2) in 2100, respectively. Among twelve economic regions of the world, the Former Soviet Union and the Other OECD Countries regions have the largest increases in potential croplands, while developing countries have little increases in potential croplands. Spatial distribution of potential croplands changes considerably over time, dependent upon the transient climate change predictions. Includes bibliographical references (p. 9-12).; Abstract in HTML and technical report in HTML and PDF available on the Massachusetts Institute of Technology Joint Program on the Science and Policy of Global Change website (http://mit.edu/globalchange/www/).

Joint implementation : lessons from Title IV's voluntary compliance programs

1997-06-01T00:00:00Z

Joint implementation : lessons from Title IV's voluntary compliance programs This paper is based on a Master of Science thesis submitted to the MIT Technology and Policy Program in May, 1997, and also appeared as Working Paper 97-003 in the MIT Center for Energy and Environmental Policy Research (CEEPR) series.; Includes bibliographical references (p. 29-31).; Abstract in HTML and technical report in HTML and PDF available on the Massachusetts Institute of Technology Joint Program on the Science and Policy of Global Change website (http://mit.edu/globalchange/www/).

Parameterization of urban sub-grid scale processes in global atmospheric chemistry models

1997-07-01T00:00:00Z

Parameterization of urban sub-grid scale processes in global atmospheric chemistry models We have derived a parameterization consisting of a set of analytical expressions that approximate the predictions by the CIT Urban Airshed Model for the net export to the environment (i.e., effective emissions) of several chemical species, as functions of fourteen input parameters. For each species, effective emissions are a function of actual urban emissions of this and other species and of other urban domain properties such as meteorology. Effective emissions may be "aged" emissions of primary pollutants or actual production of secondary pollutants. To develop the parameterization we have applied the probabilistic collocation method, which uses the probability density functions of the inputs to generate a set of orthogonal polynomials. These polynomials are then used as the basis for a polynomial chaos expansion that approximates the actual response of the CIT model to its inputs. We assume that seasonal variations can be represented by sinusoidal functions. The parameterization provides a computationally very efficient simulation of the actual model behavior. We have compared the outputs of the parameterization with the outputs of the CIT model, and we conclude that it gives a quite good approximation for effective emissions, at least in the regions of highest probability of the input parameters. This parameterization is applicable to detailed uncertainty and sensitivity analyses and enables computationally efficient inclusion of urban-scale processes as sub-grid scale phenomena in global-scale models. Includes bibliographical references (p. 29-30).; Abstract in HTML and technical report in HTML and PDF available on the Massachusetts Institute of Technology Joint Program on the Science and Policy of Global Change website (http://mit.edu/globalchange/www/).

Is international emissions trading always beneficial?

2002-12-01T00:00:00Z

Is international emissions trading always beneficial? Babiker, Mustafa H.M.; Reilly, John M.; Viguier, Laurent L. Economic efficiency is a major argument for the inclusion of an international emission permit trading system under the Kyoto Protocol. Using a partial equilibrium framework, energy system models have shown that implementing tradable permits for greenhouse gases internationally could reduce compliance costs associated with the emission targets. However, we show that international emission trading could be welfare decreasing under a general equilibrium framework. We describe a case of immiserizing growth in the sense of Bhagwati where the negative terms of trade and tax-interaction effects wipeout the primary income gains from emission trading. Immiserizing emission trading occurs only when there are pre-existing distortions in the economy. Simulation results based on a CGE model developed at MIT (the EPPA model) show that under an EU-wide emission trading regime the introduction of a permit trading system cause welfare losses for some of the trading countries. Abstract in HTML and technical report in PDF available on the Massachusetts Institute of Technology Joint Program on the Science and Policy of Global Change website (http://mit.edu/globalchange/www/).

Needed : a realistic strategy for global warming

1997-08-01T00:00:00Z

Needed : a realistic strategy for global warming Through a brief look at the science and economics of climate, the authors show that if climate change turns out to be a serious threat, an effective response will require a substantial and very long-term global effort. Today's focus on near-term emissions reductions will be counter-productive if it delays development of the institutions and policy architectures that would be necessary to mount and sustain such an effort over much of the next century. The authors discuss three legacies that our generation could leave that would make this struggle to devise a global response easier: (1) an international climate agreement that could, if necessary, reduce greenhouse gas emissions substantially, at least cost, while being responsive both to changes in our scientific understanding and to evolving political and economic conditions, (2) enhanced technical options that could, if necessary, ease the task of maintaining economic growth while controlling greenhouse gas emissions, and (3) an international system that could, if necessary, transfer substantial sums to developing countries to assist their participation in an emissions control effort. Building these legacies is a huge challenge, but this task merits at least the same sense of urgency that has motivated pre-Kyoto negotiations about short-term CO2 emissions reductions. Abstract in HTML and technical report in HTML and PDF available on the Massachusetts Institute of Technology Joint Program on the Science and Policy of Global Change website (http://mit.edu/globalchange/www/).

Same science, differing policies : the saga of global climate change

1997-08-01T00:00:00Z

Same science, differing policies : the saga of global climate change This paper provides a comparative analysis of the economic and political interests influencing the progress of climate negotiation. The primary focus is on the U.S., France, Germany, U.K., Belgium, Netherlands, and the E.U. itself. A discussion of the drivers of policy and differing responses on a national basis is presented to highlight the larger influences at work. The driving factors range across economic and political interests, public concern, bureaucratic goals, scientific evidence, non-governmental organizations, energy industries, and are relevant in each country to varying degrees. Also included is a personal forecast of what can be expected to emerge in the next few months as the current negotiations reach their climax in Kyoto, Japan, in December 1997. Includes bibliographical references.; Abstract in HTML and technical report in HTML and PDF available on the Massachusetts Institute of Technology Joint Program on the Science and Policy of Global Change website (http://mit.edu/globalchange/www/)

Uncertainty in the oceanic heat and carbon uptake and their impact on climate projections

1997-09-01T00:00:00Z

Uncertainty in the oceanic heat and carbon uptake and their impact on climate projections The impact of uncertainty in the rate of heat and carbon uptake by the deep ocean on climate response to increases in greenhouse gas concentrations is studied by means of numerical simulations with the two-dimensional climate-chemistry model developed in the framework of the MIT Global Change Joint Program. This model incorporates parameterizations of most physical processes, includes fully interactive atmospheric chemistry and calculates carbon uptake by the ocean and, therefore, simulates the main nonlinear interactions taking place in the climate system. At the same time, it is much more computationally efficient than coupled atmosphere-ocean general circulation models. Results of the simulations with calculated CO2 concentrations are compared with those of simulations with a prescribed CO2 increase. This comparison shows that the uncertainty in the increase in global mean surface temperature due to uncertainty in the rate of oceanic heat uptake is enhanced by taking into account the related uncertainty in oceanic carbon uptake, while the uncertainty in sea level rise is decreased. Includes bibliographical references (p. 5).; Abstract in HTML and technical report in HTML and PDF available on the Massachusetts Institute of Technology Joint Program on the Science and Policy of Global Change website (http://mit.edu/globalchange/www/)

A global interactive chemistry and climate model : formulation and testing

1997-09-01T00:00:00Z

A global interactive chemistry and climate model : formulation and testing Abstract in HTML and technical report in HTML and PDF available on the Massachusetts Institute of Technology Joint Program on the Science and Policy of Global Change website (http://mit.edu/globalchange/www/).; Includes bibliographical references (p. 12-14).

Interactions among emissions, atmospheric chemistry, and climate change : implications for future trends

1997-09-01T00:00:00Z

Interactions among emissions, atmospheric chemistry, and climate change : implications for future trends Abstract in HTML and technical report in HTML and PDF available on the Massachusetts Institute of Technology Joint Program on the Science and Policy of Global Change website (http://mit.edu/globalchange/www/).; Includes bibliographical references (p. 9-10).

Necessary conditions for stabilization agreements

1997-10-01T00:00:00Z

Necessary conditions for stabilization agreements The Climate Convention calls for stabilization of atmospheric concentrations of greenhouse gases. This paper considers the issues that must be faced in formulating a plan to meet any such target, using a proposed CO2 level of 550 ppmv as an example. We hypothesize a set of "necessary conditions" for such a goal to be achievable, and test set of possible forms of agreement against them using the MIT Emissions Prediction and Policy Assessment (EPPA) model. The results highlight the importance of emissions trading to the feasibility of such a target, and the need for an agreement that can adapt efficiently over time to changing relative economic circumstances in participating nations. Includes bibliographical references (p. 19).; Abstract in HTML and technical report in HTML and PDF available on the Massachusetts Institute of Technology Joint Program on the Science and Policy of Global Change website (http://mit.edu/globalchange/www/)

Annex I differentiation proposals : implications for welfare, equity and policy

1997-10-01T00:00:00Z

Annex I differentiation proposals : implications for welfare, equity and policy Drawing upon a variety of different criteria, many nations have introduced proposals to differentiate the reductions in carbon emissions that would be required of industrialized nations in the short to medium term. This paper considers the relationship of these proposals to their underlying conceptions of equity, and to the self-interest of the nations proposing them. The MIT Emissions Prediction and Policy Assessment (EPPA) model is used to analyze the welfare implications of several prominent proposals, considering both cases where nations must carry out all emissions reductions domestically, and situations where trading in emissions permits is allowed. The consequences of applying two prominent differentiation measures to a global regime using a zero-based allocation of emissions rights is also explored. One conclusion is that a trading regime can yield important benefits in reducing potential conflict within developed nations, and help avoid complicated and divisive negotiations over burden-sharing formulas. Includes bibliographical references (p. 19-20).; Abstract in HTML and technical report in HTML and PDF available on the Massachusetts Institute of Technology Joint Program on the Science and Policy of Global Change website (http://mit.edu/globalchange/www/)

Transient climate change and net ecosystem production of the terrestrial biosphere

1997-11-01T00:00:00Z

Transient climate change and net ecosystem production of the terrestrial biosphere The Terrestrial Ecosystem Model (TEM version 4.1) is applied to assess the sensitivity of net ecosystem production (NEP) of the terrestrial biosphere to transient changes in atmospheric CO2 concentration and climate in the 21st century. These NEP estimates provide a measure of the potential for various vegetated regions and countries to act as sinks or sources of atmospheric CO2. We use three transient climate change predictions over the period of 1977-2100 from the MIT Integrated Global System Model for assessment of the effects of different climate changes. Global annual NEP has large interannual variations and increases over time, thus representing a growing net carbon flux from the atmosphere to the biosphere. Latitudinal distribution of total annual NEP along 0.5 degree resolution latitudinal bands has a significant shift from the tropics to the northern mid- and high-latitudes over time. The sums of annual NEP over the period of 1990-2100 differ substantially among the twelve economic regions of the world. The results show that temporal dynamics and spatial distribution of annual NEP are very sensitive to the magnitudes and paths of temporal changes in atmospheric CO2 concentration and climate. Includes bibliographical references (p. 13-16).; Abstract in HTML and technical report in HTML and PDF available on the Massachusetts Institute of Technology Joint Program on the Science and Policy of Global Change website (http://mit.edu/globalchange/www/)

Analysis of CO₂ emissions from fossil fuel in Korea : 1961-1994

1997-11-01T00:00:00Z

Analysis of CO₂ emissions from fossil fuel in Korea : 1961-1994 Includes bibliographical references (p. 14).; Abstract in HTML and technical report in HTML and PDF available on the Massachusetts Institute of Technology Joint Program on the Science and Policy of Global Change website (http://mit.edu/globalchange/www/)

Uncertainty in future carbon emissions : a preliminary exploration

1997-11-01T00:00:00Z

Uncertainty in future carbon emissions : a preliminary exploration In order to analyze competing policy approaches for addressing global climate change, a wide variety of economic-energy models are used to project future carbon emissions under various policy scenarios. Due to uncertainties about future economic growth and technological development, there is a great deal of uncertainty in emissions projections. This paper demonstrates the use of the Deterministic Equivalent Modeling Method, an efficient means for propagating uncertainty through large models, to investigate the probability distributions of carbon emissions from the MIT Emissions Prediction and Policy Analysis model. From the specific results of the uncertainty analysis, several conclusions with implications for climate policy are given, including the existence of a wider range of possible outcomes than suggested by differences between models, the fact that a "global emissions path through time" does not actually exist, and that the uncertainty in costs and effects of carbon reduction policies differ across regions. Includes bibliographical references (p. 31-32).; Abstract in HTML and technical report in HTML and PDF available on the Massachusetts Institute of Technology Joint Program on the Science and Policy of Global Change website (http://mit.edu/globalchange/www/)

Modeling non-CO₂ greenhouse gases

2002-12-01T00:00:00Z

Modeling non-CO₂ greenhouse gases Hyman, Robert C.; Reilly, John M.; Babiker, Mustafa H.M.; De Masin, Ardoin. Although emissions of CO₂ are the largest anthropogenic contributor to the risks of climate change, other substances are important in the formulation of a cost-effective response. To provide improved facilities for addressing their role, we develop an approach for endogenizing control of these other greenhouse gases within a computable general equilibrium (CGE) model of the world economy. The calculation is consistent with underlying economic production theory. For parameterization it is able to draw on marginal abatement cost (MAC) functions for these gases based on detailed technological descriptions of control options. We apply the method to the gases identified in the Kyoto Protocol: methane (CH4), nitrous oxide (N2O), sulfur hexaflouride (SF6), the perflourocarbons (PFCs), and the hyrdoflourocarbons (HFCs). Complete and consistent estimates are provided of the costs of meeting greenhouse-gas reduction targets with a focus on "what" flexibility — i.e., the ability to abate the most cost-effective mix of gases in any period. We find that non-CO2 gases are a crucial component of a cost-effective policy. Because of their high Global Warming Potentials (GWPs) under current international agreements they would contribute a substantial share of early abatement. Abstract in HTML and technical report in PDF available on the Massachusetts Institute of Technology Joint Program on the Science and Policy of Global Change website (http://mit.edu/globalchange/www/).

Beyond emissions paths : rethinking the climate impacts of emissions protocols in an uncertain world

1997-11-01T00:00:00Z

Beyond emissions paths : rethinking the climate impacts of emissions protocols in an uncertain world Includes bibliographical references (p. 21-23).; Abstract in HTML and technical report in HTML and PDF available on the Massachusetts Institute of Technology Joint Program on the Science and Policy of Global Change website (http://mit.edu/globalchange/www/)

Kyoto's Unfinished Business

1998-06-01T00:00:00Z

Kyoto's Unfinished Business The authors offer a provisional assessment of where the Kyoto negotiations have left the climate change issue. They present a few widely divergent assesments of what the Kyoto Protocol on Climate Change will accomplish, and describe some differing interpretations of its text in the context of the underlying international disagreement, as well as in differing perceptions of the underlying science and economics. The paper includes a brief but up-to-date summary of what we know and don't know about human influences on climate, and what it might take to restrain them. Includes bibliographical references.; Abstract in HTML and technical report in HTML and PDF available on the Massachusetts Institute of Technology Joint Program on the Science and Policy of Global Change website (http://mit.edu/globalchange/www/)

Economic development and the structure of the demand for commerial energy

1998-04-01T00:00:00Z

Economic development and the structure of the demand for commerial energy To deepen understanding of the relation between economic development and energy demand, this study estimates the Engel curves that relate per-capita energy consumption in major economic sectors to per-capita GDP. Panel data covering up to 123 nations are employed, and measurement problems are treated both in dataset construction and in estimation. Time and country fixed effects are assumed, and flexible forms for income effects are employed. There are substantial differences among sectors in the structure of country, time, and income effects. In particular, the household sector's share of aggregate energy consumption tends to fall with income, the share of transportation tends to rise, and the share of industry follows an inverse-U pattern. Includes bibliographical references (p. 15-16).; Abstract in HTML and technical report in HTML and PDF available on the Massachusetts Institute of Technology Joint Program on the Science and Policy of Global Change website (http://mit.edu/globalchange/www/)

Combined effects of anthropogenic emissions and resultant climatic changes on atmospheric OH

1998-04-01T00:00:00Z

Combined effects of anthropogenic emissions and resultant climatic changes on atmospheric OH Using a coupled global atmospheric chemistry and climate model we have predicted the evolution of tropospheric concentrations of chemical species along with climate parameters, based on a set of economic model predictions for anthropogenic emissions of chemically and radiatively important trace gases in the next 120 years. In particular, our predictions for tropospheric hydroxyl radical (OH) concentrations indicate the potential for substantial future changes affecting both atmospheric chemistry and climate. OH is arguably the most important free radical in the troposphere because it is the primary removal mechanism for most gases entering the atmosphere, and therefore, determines the lifetimes of these species. Our research indicates that if CH4 and CO emissions continually increase as expected through the next century, the tropospheric concentration of OH could decrease by as much as 29% from its current value. As a result, the lifetime of CO in the year 2100 is predicted to lengthen by 0.6 months beyond its current value of 2 months, and the CH4 lifetime in 2100 would exceed its current value (9 years) by 2.5 years in our reference case. Includes bibliographical references.; Abstract in HTML and technical report in HTML and PDF available on the Massachusetts Institute of Technology Joint Program on the Science and Policy of Global Change website (http://mit.edu/globalchange/www/)

Impact of emissions, chemistry, and climate on atmospheric carbon monoxide : 100-year predictions from a global chemistry-climate model

1998-04-01T00:00:00Z

Impact of emissions, chemistry, and climate on atmospheric carbon monoxide : 100-year predictions from a global chemistry-climate model The possible trends for atmospheric carbon monoxide in the next 100 yr have been illustrated using a coupled atmospheric chemistry and climate model driven by emissions predicted by a global economic development model. Various model runs with different assumptions regarding emissions or model parameters have been carried out to investigate the impacts of model and emission uncertainties on the predictions. We have found complicated interactions among emissions, atmospheric chemistry, and climate regarding the distributions and evolution of CO in the atmosphere. Based on the predicted emissions of methane and carbon monoxide, the model predicts an increasing trend of carbon monoxide in the next century with a tropospheric mole fraction of CO in 2100 double its present-day value. Methane emissions are found to have the most important effect on the future atmospheric CO budget. High methane emissions cause significant depletion of tropospheric OH, increase of CO concentrations, and lengthening of lifetimes of many chemical species including CO and CH4. The global average atmospheric lifetime of CO is predicted in our reference model run to be about 0.6 month longer than its present value (~2 months). The predicted emissions of CO increase only slightly over the next century, so the impact of CO emissions on the predicted CO abundance appears to be less important than that of methane. Consequently, maintaining the emissions of CH4 at their current levels can prevent significant future changes in tropospheric chemistry, while similar controlling emissions of CO cannot achieve the same result. This study also indicates that climate variations, especially those causing changes in H2O concentrations, can influence atmospheric trends of carbon monoxide. A two-way interaction between chemistry and climate regarding CO is evident. Specifically, the budget of atmospheric CO affects the destruction of methane and the production of CO2, ozone, and sulfate aerosols and thus affects climate, while the resultant changes in climate modify the budget of CO-CH4 in turn through their effects on H2O and temperature. Includes bibliographical references (p. 11).; Abstract in HTML and technical report in HTML and PDF available on the Massachusetts Institute of Technology Joint Program on the Science and Policy of Global Change website (http://mit.edu/globalchange/www/)

Integrated global system model for climate policy assessment : feedbacks and sensitivity studies

1998-05-01T00:00:00Z

Integrated global system model for climate policy assessment : feedbacks and sensitivity studies Includes bibliographical references (p. 64-73).; Abstract in HTML and technical report in HTML and PDF available on the Massachusetts Institute of Technology Joint Program on the Science and Policy of Global Change website (http://mit.edu/globalchange/www/)

Quantifying the uncertainty in climate predictions

1998-07-01T00:00:00Z

Quantifying the uncertainty in climate predictions Includes bibliographical references (p. 22-23).; Abstract in HTML and technical report in HTML and PDF available on the Massachusetts Institute of Technology Joint Program on the Science and Policy of Global Change website (http://mit.edu/globalchange/www/)

Sequential climate decisions under uncertainty : an integrated framework

1998-09-01T00:00:00Z

Sequential climate decisions under uncertainty : an integrated framework In this paper, we present an integrated framework for structuring and evaluating sequential greenhouse gas abatement policies under uncertainty. The analysis integrates information concerning the magnitude, timing, and impacts of climate change with data on the likely effectiveness and cost of possible response options, using reduced-scale representations of the global climate system drawn from the MIT Integrated Global System Model. To illustrate the method, we explore emissions control policies of the form considered under the United Nations Framework Convention on Climate Change. Includes bibliographical references (p. 27-28).; Abstract in HTML and technical report in HTML and PDF available on the Massachusetts Institute of Technology Joint Program on the Science and Policy of Global Change website (http://mit.edu/globalchange/www/)

Analysis of post-Kyoto CO₂ emissions trading using marginal abatement curves

1998-10-01T00:00:00Z

Analysis of post-Kyoto CO₂ emissions trading using marginal abatement curves Marginal abatement curves (MACs) are often used heuristically to demonstrate the advantages of emissions trading. In this paper, the authors derive MACs from EPPA, the MIT Joint Program's computable general equilibrium model of global economic activity, energy use and CO₂ emissions, to analyze the benefits of emissions trading in achieving the emission reduction targets implied by the Kyoto Protocol. The magnitude and distribution of the gains from emissions trading are examined for both an Annex B market and for full global trading, as well as the effects of import limitations, non-competitive behavior, and less than fully efficient supply. In general, trading benefits all parties at least some, and from a global standpoint, the gains from trading are greater, the wider and less constrained is the market. The distribution of the gains from trading is, however, highly skewed in favor of those who would face the highest costs in the absence of emissions trading. Includes bibliographical references.; Abstract in HTML and technical report in HTML and PDF available on the Massachusetts Institute of Technology Joint Program on the Science and Policy of Global Change website (http://mit.edu/globalchange/www/)

The effects on developing countries of the Kyoto Protocol and CO₂ emissions trading

1998-11-01T00:00:00Z

The effects on developing countries of the Kyoto Protocol and CO₂ emissions trading This paper examines the effect of the Kyoto Protocol on developing economies using marginal abatement curves generated by MIT's Emissions Prediction and Policy Assessment model (EPPA). In particular, the paper addresses how developing countries are affected by the scope of CO2 emissions trading, by various limitations that Annex I countries might place on emissions trading, by the nature of the Clean Development Mechanism, and by changes in the international trade flows in conventional goods and services. In general, it is found that developing countries benefit from emissions trading, both from the new export opportunities and by the lesser distortion of Annex I economies. This effect is particularly pronounced for energy exporting countries since Annex I countries are able to substitute cheaper reductions of coal emissions in developing countries for more expensive reductions of oil emissions within Annex I. The paper also highlights the implications of the apparent inelastic demand for tradable permits from non-Annex I countries and the conflict between revenue maximization and other goals assigned to the Clean Development Mechanism. Includes bibliographical references (p. 22-23).; Abstract in HTML and technical report in HTML and PDF available on the Massachusetts Institute of Technology Joint Program on the Science and Policy of Global Change website (http://mit.edu/globalchange/www/)

Market power in international carbon emissions trading: a laboratory test

2003-01-01T00:00:00Z

Market power in international carbon emissions trading: a laboratory test Carlén, Björn. The prospect that governments of one or a few large countries, or trading blocs, would engage in international greenhouse gas emissions trading has led several policy analysts to express concerns that trade would be influenced by market power. The experiment reported here mimics a case where twelve countries, one of which is a large buyer (the mirror-image of a large seller), trade carbon emissions on an emissions exchange (a double-auction market) and where traders have quite accurate information about the underlying net demand. The findings deviate from those of the standard version of market power effects in that trade volumes and prices converge on competitive levels. Abstract in HTML and technical report in PDF available on the Massachusetts Institute of Technology Joint Program on the Science and Policy of Global Change website (http://mit.edu/globalchange/www/).

Obstacles to global CO₂ trading : a familiar problem

1998-11-01T00:00:00Z

Obstacles to global CO₂ trading : a familiar problem There are many obstacles to the development of an international CO₂ emissions trading system, but the biggest is a feature that is often assumed: the existence of a single national system. Once a national system is in place, an international system will develop naturally more as a matter of self-interested trade than as international agreement. Meeting the Kyoto targets will create a scarcity; and the scarcity requires that use and the associated rent be allocated somehow. This allocation — deciding who gets what — is a familiar problem and the largest impediment to the creation of a national system, and thus of an international regime of CO₂ emissions trading. The paper reviews the various instruments by which such the Kyoto target might be met from the standpoint of the allocation of the scarce use and the associated rent. In particular, the paper emphasizes that existing users will largely continue to use the scarce resource and that they now actively exercise the incipient right to the proposed scarcity. Creation of the scarcity and the allocation of rights raise fundamental issues of equity that lie pre-eminently in the political realm. The author observes that the creation of the scarcity and the allocation of rights are fused and that agreement on one will occur only as there is agreement on the other. Nevertheless, such problems have been solved before — for land and for SO₂ permits — although in both cases the conditions were easier than what is now proposed for CO₂. An international CO₂ trading system will develop from a national allowance system for the same reasons that trading can be expected to occur domestically. However, the unavoidable requirement of certification and verification will impede access to non-Annex B sources of emission reduction, and at the same time encourage countries with such sources to accept Annex B limits. The negotiation of such limits raises the same problems of allocation as faced at the national level, only on a global scale; and there is even less agreement here. Nevertheless, the discussion on global allocation will not begin in earnest until a national system creates the trade opportunities that will make an Annex B limit worth pursuing. The development of an international system for CO₂ emissions trading should not be expected to be either quick or easy, but to occur only by accretion and mostly as a matter of self-interested trade. Includes bibliographical references (p. 12).; Abstract in HTML and technical report in HTML and PDF available on the Massachusetts Institute of Technology Joint Program on the Science and Policy of Global Change website (http://mit.edu/globalchange/www/)

The uses and misuses of technology development as a component of climate policy

1998-11-01T00:00:00Z

The uses and misuses of technology development as a component of climate policy The current misplaced focus on short-term climate policies is a product both of domestic political exigencies and badly flawed technical analyses. A prime example of the latter is a recent U.S. Department of Energy study, prepared by five national laboratories. The 5-Labs study assumes —- incorrectly —- that technical solutions are readily at hand. Worse, advocates of short-term emissions targets under the Framework Convention on Climate Change are using this study to justify the subsidy of existing energy technologies —- diverting resources from the effective long-term technology response that will be needed if the climate picture darkens. Includes bibliographical references (p. 15-16).; Abstract in HTML and technical report in HTML and PDF available on the Massachusetts Institute of Technology Joint Program on the Science and Policy of Global Change website (http://mit.edu/globalchange/www/)

Primary aluminum production : climate policy, emissions and costs

1998-12-01T00:00:00Z

Primary aluminum production : climate policy, emissions and costs Climate policy regarding perfluorocarbons (PFCs) may have a significant influence on investment decisions in the production of primary aluminum. This work demonstrates an integrated analysis of the effectiveness and likely economic consequences of different climate policy options. In our study we first compare atmospheric observations to the available estimates of PFC emissions for the baseline years 1990 and 1995. We then present projections for regional emissions of PFCs from the aluminum industry using the MIT Emissions Projection and Policy Analysis model under different policy scenarios. Abatement costs for emissions of PFCs and CO2 are compared in the context of the Kyoto Protocol. Includes bibliographical references (p. 17-18).; Abstract in HTML and technical report in HTML and PDF available on the Massachusetts Institute of Technology Joint Program on the Science and Policy of Global Change website (http://mit.edu/globalchange/www/)

Multi-gas assessment of the Kyoto protocol

1999-01-01T00:00:00Z

Multi-gas assessment of the Kyoto protocol The Kyoto Protocol is an international agreement aimed at limiting emissions of several greenhouse gases (GHGs; specifically: CO2, CH4, N2O, PFCs, HFCs, and SF6), and allows credit for approved sinks for CO2. It does not include consideration of several other trace atmospheric constituents that have important indirect effects on the radiative budget of the atmosphere. Here we show that inclusion of other GHGs and CO2 sinks greatly reduces the cost of achieving CO2 emissions reductions specified under the agreement. The Kyoto Protocol extrapolated to 2100 reduces predicted warming by only about 17%. The errors caused by simulating other GHGs with scaled amounts of CO2 on atmospheric composition, climate, and ecosystems are small. Larger errors come from failure to account for interactive and climatic effects of gases that affect atmospheric composition but are not included in the protocol (CO, NOx, and SOx). Over the period to 2100, the Global Warming Potential (GWP) indices based on a 100-year time horizon as specified in the protocol appear to be an adequate representation of trace gas climatic effects. The principal reason for the success of this simplified GWP approach in our calculations is that the mix of gas emissions resulting from a carbon-only rather than a multi-gas control strategy does not change by a large amount. Includes bibliographical references (p. 13-14).; Abstract in HTML and technical report in HTML and PDF available on the Massachusetts Institute of Technology Joint Program on the Science and Policy of Global Change website (http://mit.edu/globalchange/www/)

From science to policy : the science-related politics of climate change policy in the U.S.

1999-01-01T00:00:00Z

From science to policy : the science-related politics of climate change policy in the U.S. Global climate change is on the political agenda primarily as a result of science and the warnings of the scientific community, and is commonly seen as a quintessentially scientific matter. However, the development of policy on this issue in the U.S. today does not turn on the scientific evidence. Rather, policy is determined by the political and economic forces involved, with reference to the science only to support positions reached on other grounds. The reasons relate primarily to the uncertainty in the evidence, the structure and politics of the government, the economic costs and impact of change and of policies to reduce greenhouse gases, the international structure in which the issue is being confronted, the role of the media, and the effects of partisan politics. In this situation, the scientific and engineering communities (including social scientists and especially economists) have a major responsibility to maintain their professional values and objectivity so dominated at the moment by other pressures. Only that way can they retain the public trust that will be necessary if and when costly policy measures must be undertaken. Includes bibliographical references.; Abstract in HTML and technical report in HTML and PDF available on the Massachusetts Institute of Technology Joint Program on the Science and Policy of Global Change website (http://mit.edu/globalchange/www/)

Constraining uncertainties in climate models using climate change detection techniques

1999-04-01T00:00:00Z

Constraining uncertainties in climate models using climate change detection techniques Different atmosphere-ocean general circulation models produce significantly different projections of climate change in response to increases in greenhouse gases and aerosol concentrations in the atmosphere. The main reasons for this disagreement are differences in the sensitivities of the models to external radiative forcing and differences in their rates of heat uptake by the deep ocean. In this study, these properties are constrained by comparing radiosonde-based observations of temperature trends in the free troposphere and lower stratosphere with corresponding simulations of a fast, flexible climate model, using techniques based on optimal fingerprinting. Parameter choices corresponding either to low sensitivity, or to high sensitivity combined with slow oceanic heat uptake are rejected. Nevertheless, a broad range of acceptable model characteristics remains, such that climate change projections from any single model should be treated as only one of a range of possibilities. Includes bibliographical references (p. 10-11).; Abstract in HTML and technical report in HTML and PDF available on the Massachusetts Institute of Technology Joint Program on the Science and Policy of Global Change website (http://mit.edu/globalchange/www/)

Adjusting to policy expectations in climate change modeling : an interdiciplinary study of flux adjustments in coupled atmosphere-ocean general circulation models

1999-05-01T00:00:00Z

Adjusting to policy expectations in climate change modeling : an interdiciplinary study of flux adjustments in coupled atmosphere-ocean general circulation models This paper surveys and interprets the attitudes of scientists to the use of flux adjustments in climate projections with coupled Atmosphere Ocean General Circulation Models. The survey is based largely on the responses of 19 climate modellers to several questions and a discussion document circulated in 1995. We interpret the responses in terms of the following factors: the implicit assumptions which scientists hold about how the environmental policy process deals with scientific uncertainty over human-related global warming; the different scientific styles that exist in climate research; and the influence of organisations, institutions, and policy upon research agendas. We find evidence that scientists' perceptions of the policy process do play a role in shaping their scientific practices. In particular, many of our respondents expressed a preference for keeping discussion of the issue of flux adjustments within the climate modeling community, apparently fearing that climate contrarians would exploit the issue in the public domain. While this may be true, we point to the risk that such an approach may backfire. We also identify assumptions and cultural commitments lying at a deeper level which play at least as important a role as perceptions of the policy process in shaping scientific practices. This leads us to identify two groups of scientists, 'pragmatists' and 'purists,' who have different implicit standards for model adequacy, and correspondingly are or are not willing to use flux adjustments. Includes bibliographical references.; Abstract in HTML and technical report in HTML and PDF available on the Massachusetts Institute of Technology Joint Program on the Science and Policy of Global Change website (http://mit.edu/globalchange/www/)

Toward a useful architecture for climate change negotiations

1999-05-01T00:00:00Z

Toward a useful architecture for climate change negotiations Years of hard bargaining have failed to produce a policy architecture to adequately address the complexities of climate change. Very likely, such a structure will have to be sought though improvement of the partial architecture developed to date within the Framework Convention on Climate Change. We identify key architectural features that have emerged in the Convention process, and then explore extensions that will be necessary if the current approach is to serve for the long term. An important task is to break the deadlock over accession of developing countries. To this end we propose further incorporation in the negotiations of concepts of burden sharing according to ability to pay that already seem to be embedded in the Convention. The implications of alternative versions of such an approach are illustrated with a set of simple model simulations. Includes bibliographical references (p. 23-24).; Abstract in HTML and technical report in HTML and PDF available on the Massachusetts Institute of Technology Joint Program on the Science and Policy of Global Change website (http://mit.edu/globalchange/www/)

A study of the effects of natural fertility, weather and productive inputs in Chinese agriculture

1999-07-01T00:00:00Z

A study of the effects of natural fertility, weather and productive inputs in Chinese agriculture This paper presents an investigation of the relations in China between farm output, the natural fertility of agricultural land, and the use of anthropogenic farm inputs. The methodology is presented as a potential increment to the analysis of the effects of climate change in agriculture. Variations of climate, soil and topographic conditions, and direct farm inputs across the prefectures of China are used to determine their effects on the output of particular crops. The study estimates crop production functions with conventional land, labor, fertilizer and mechanical inputs, and the net primary productivity (NPP) projections of the Terrestrial Ecosystems Model to reflect climatic conditions. Estimates of the NPP of the land in each prefecture are used to simulate the effects of climate and other natural growing conditions. The results suggest that there is substantial scope for increasing food production in China by increasing its irrigation of farm land and the use of farm inputs of fertilizer and mechanical power. Includes bibliographical references (p. 15).; Abstract in HTML and technical report in HTML and PDF available on the Massachusetts Institute of Technology Joint Program on the Science and Policy of Global Change website (http://mit.edu/globalchange/www/)

Japanese nuclear power and the Kyoto agreement

1999-08-01T00:00:00Z

Japanese nuclear power and the Kyoto agreement We find that, on an economic basis, nuclear power could make a substantial contribution for meeting the emissions target Japan agreed to in the Kyoto Protocol. It is unlikely however that the contribution would be as large as projected in official Japanese forecasts. The economic costs of the carbon constraint rise if siting, construction, and approval problems prevent the economically desirable level of expansion of nuclear power. We also evaluate the economic effects of subsidizing nuclear power to achieve the expansion projected in official forecasts. While the subsidy required is substantial, the economic welfare effects are relatively small because of second-best considerations. We use the EPPA model, a global computable general equilibrium model, in the analysis. Our estimates thus include the effects of changing world energy prices and terms of trade as they affect competitiveness of nuclear power and economic welfare. Includes bibliographical references (p. 12).; Abstract in HTML and technical report in HTML and PDF available on the Massachusetts Institute of Technology Joint Program on the Science and Policy of Global Change website (http://mit.edu/globalchange/www/)

Emissions trading to reduce greenhouse gas emissions in the United States : the McCain-Lieberman Proposal

2003-06-01T00:00:00Z

Emissions trading to reduce greenhouse gas emissions in the United States : the McCain-Lieberman Proposal Paltsev, Sergey.; Reilly, John M.; Jacoby, Henry D.; Ellerman, A. Denny.; Tay, Kok Hou. The Climate Stewardship Act of 2003 (S. 139) is the most detailed effort to date to design an economy-wide cap-and-trade system for US greenhouse gas emissions reductions. The Act caps sectors at their 2000 emissions in Phase I of the program, running from 2010 to 2015, and then to their 1990 emissions in Phase II starting 2016. There is a strong incentive for banking of allowances, raising the costs in Phase I to achieve savings in Phase II. Use of credits from outside the capped sectors could significantly reduce the cost of the program, even though limited to 15% and 10% of Phase I and II allowances respectively. These credits may come from CO2 sequestration in soils and forests, reductions in emissions from uncapped sectors, allowances acquired from foreign emissions trading systems, and from a special incentive program for automobile manufacturers. The 15% and 10% limits increase the incentive for banking and could prevent full use of cost-effective reductions from the uncapped sectors. Moreover, some of the potential credits might contribute little or no real climate benefit, particularly if care is not taken in defining those from forest and soil CO2 sequestration. Analysis using the MIT Emissions Prediction and Policy Analysis model shows that costs over the two Phases of the program could vary substantially, depending on normal uncertainty in economic and emissions growth, and the details of credit system implementation. Abstract in HTML and technical report in PDF available on the Massachusetts Institute of Technology Joint Program on the Science and Policy of Global Change website (http://mit.edu/globalchange/www/).

Interactive chemistry and climate models in global change studies

1999-09-01T00:00:00Z

Interactive chemistry and climate models in global change studies Continually increasing atmospheric concentrations of radiatively important chemical species such as CO2, CH4, N2O, tropospheric O3, and certain halocarbons most likely will cause future climate changes, which could in turn impact chemical reaction rates and thus lifetimes of many important chemical species. Complicated interactions between climate dynamics and atmospheric chemistry strongly suggest that a fully interactive, comprehensive chemistry-climate modeling system is needed to study the issue. This article reviews recent work in the new and challenging field of interactive chemistry-climate modeling, describing major efforts in model development and summarizing in detail applications of and results from these models. Includes bibliographical references (p. 12-16).; Abstract in HTML and technical report in PDF available on the Massachusetts Institute of Technology Joint Program on the Science and Policy of Global Change website (http://mit.edu/globalchange/www/)

Developing country effects of Kyoto-type emissions restrictions

1999-10-01T00:00:00Z

Developing country effects of Kyoto-type emissions restrictions Economic links among countries, through trade, will cause the effects of greenhouse-gas control measures taken by one set of nations to ripple through the international trade system, affecting countries that may not have agreed to share the burdens of control. So, for example, emission restrictions under the Kyoto Protocol will increase the cost to Annex B regions of using carbon-emitting fuels and raise the manufacturing cost of their energy-intensive goods, which may be exported in part to developing countries. The restrictions also will lower the global demand for these fuels and reduce their international prices. In addition, the emissions controls may depress the level of economic activity in countries under emissions restriction, lowering their demand for imports, some of which come from developing countries. In combination, these changes in trade volumes and prices can have complex consequences, harming some developing countries while benefiting others. This paper explores these consequences using a detailed Computable General Equilibrium (CGE) model of the world economy. Includes bibliographical references (p. 26-28).; Abstract in HTML and technical report in PDF available on the Massachusetts Institute of Technology Joint Program on the Science and Policy of Global Change website (http://mit.edu/globalchange/www/)

Model estimates of the mass balance of the Greenland and Antartic ice sheets

1999-10-01T00:00:00Z

Model estimates of the mass balance of the Greenland and Antartic ice sheets The six possible combinations of two climate models and three methods for calculating the melting of snow and ice are used to estimate current values of accumulation and ablation on the Greenland and Antarctic ice sheets. This allows the contrasting of high vs. low resolution climate input and to assess the reliability of simple temperature based parameterizations of melting when compared to a physical model of the seasonal evolution of the snow cover. In contrast to past efforts at modelling the mass balance of Greenland and Antarctica, the latter model allows an explicit calculation of the formation of meltwater, of the fraction of meltwater which refreezes and of runoff in the ablation region, this is not the case for the other two melt models. While the higher resolution GCM (ECHAM 4) does bring the estimation of accumulation closer to observations, it fails to give accurate results in its predictions of runoff. The simpler climate model (MIT 2D LO) overestimates accumulation in Antarctica but produces satisfactory estimates of runoff from the Greenland ice sheet. Both models reproduce some of the characteristics of the extent of the wet snow zone observed with satellite remote sensing, but the MIT model is closer to observations in terms of areal extent and intensity of the melting. The temperature dependent melting parameterizations generally require an accuracy in the climatic input beyond what is currently achieved to produce reliable. Because it is based on physical principles and relies on the surface energy balance as input, the snow cover model is believed to have the capability to respond adequately to the current climatic forcing as well as to future changes in climate. Includes bibliographical references (p. 31-34).; Abstract in HTML and technical report in HTML and PDF available on the Massachusetts Institute of Technology Joint Program on the Science and Policy of Global Change website (http://mit.edu/globalchange/www/)

Changes in sea-level associated with modifications on the mass balance of the Greenland and Antartic ice sheets over the 21st century

1999-10-01T00:00:00Z

Changes in sea-level associated with modifications on the mass balance of the Greenland and Antartic ice sheets over the 21st century Changes in runoff from Greenland and Antarctica are often cited as one of the major concerns linked to anthropogenic changes in climate. The changes in mass balance, and associated changes in sea-level, of these two ice sheets are examined by comparing the predictions of the six possible combinations of two climate models and three methods for estimating melting and runoff. All models are solved on 20 and 40 km grids respectively for Greenland and Antarctica. The two temperature based runoff parameterizations give adequate results for Greenland, less so for Antarctica. The energy balance based approach, which relies on an explicit modelling of the temperature and density structure within the snow cover, gives similar results when coupled to either climate model. The Greenland ice sheet, for a reference climate scenario similar to the IPCC's IS92a, is not expected to contribute significantly to changes in the level of the ocean over the 21st century. The changes in mass balance in Antarctica are dominated by the increase in snowfall, leading to a decrease in sea-level of 4 cm by 2100. The range of uncertainty in these predictions is estimated by repeating the calculation with the simpler climate model for seven climate change scenarios. Greenland would increase the level of the oceans by 0 - 2 cm, while Antarctica would decrease it by 2.5 - 6.5 cm. The combined effect of both ice sheets lowers the sea-level by 2.5 - 4.5 cm over the next 100 years, this represents a 25% reduction of the sea-level rise estimated from thermal expansion alone. This surprisingly small range of uncertainty is due to cancellations between the effects of the two ice sheets. For the same reason, the imposition of the Kyoto Protocol has no impact on the prediction of sea-level change due to changes in Greenland and Antarctica, when compared to a reference scenario in which emissions are allowed to grow unconstrained. Includes bibliographical references (p. 26-28).; Abstract in HTML and technical report in HTML and PDF available on the Massachusetts Institute of Technology Joint Program on the Science and Policy of Global Change website (http://mit.edu/globalchange/www/)

The Kyoto Protocol and developing countries

1999-10-01T00:00:00Z

The Kyoto Protocol and developing countries Under the Kyoto Protocol, the world's wealthier countries assumed binding commitments to reduce greenhouse gas emissions. The agreement requires these countries to consider ways to minimize adverse effects on developing countries of these actions, transmitted through trade. Using a general equilibrium model of the world economy, we find that adverse effects fall mainly on energy-exporting countries, for some even greater than on countries that are assuming commitments. Removing existing fuel taxes and subsidies and using international permit trading would greatly reduce the adverse impacts and also reduce economic impacts on the countries taking on commitments. Another approach, preferential tariff reduction for developing countries, would benefit many developing countries, but would not target those most adversely affected. If instead, OECD countries directly compensated developing countries for losses, the required annual financial transfer would be on the order of $25 billion (1995 $US) in 2010. Includes bibliographical references (p. 19-20).; Abstract in HTML and technical report in PDF available on the Massachusetts Institute of Technology Joint Program on the Science and Policy of Global Change website (http://mit.edu/globalchange/www/)

A game of climate chicken : can EPA regulate greenhouse gases before the U.S. Senate ratifies the Kyoto Protocol?

1999-11-01T00:00:00Z

A game of climate chicken : can EPA regulate greenhouse gases before the U.S. Senate ratifies the Kyoto Protocol? EPA's legal authority to regulate greenhouse gas emissions under the Clean Air Act is reviewed. While EPA clearly does not have the authority to implement the precise terms of the Kyoto Protocol, arguments could be put forward to support the Agency's claim that it has the authority to control such pollutants. However, the Clean Air Act's legislative history, a textual analysis of the Act, judicial precedents and political considerations all provide compelling arguments for the EPA to seek additional legislation before attempting to regulate greenhouse gases. Even a generous interpretation of existing provisions would prohibit trading in greenhouse gas emissions permits and therefore contradicts the Administration's own preferred approach to addressing climate change which favors employing market mechanisms to help reduce the costs of carrying out reductions. Moreover, the participation of developing countries in an emissions control regime, which has been stipulated by the Senate and endorsed by the Administration, would also remain unaffected since the Clean Air Act is only designed to address local and regional pollution. Concerns over backdoor implementation of the Kyoto Protocol and EPA's attempts to regulate emissions help explain the political attacks on the agency's efforts to pursue research, education, and non-regulatory solutions to the climate change problem. Includes bibliographical references.; Abstract in HTML and technical report in PDF available on the Massachusetts Institute of Technology Joint Program on the Science and Policy of Global Change website (http://mit.edu/globalchange/www/)

Multiple gas control under the Kyoto agreement

2000-03-01T00:00:00Z

Multiple gas control under the Kyoto agreement Under the Kyoto Protocol, reductions in emissions of several radiative gases can be credited against a carbon equivalent emissions cap. We investigate the economic implications of including other greenhouse gases and sinks in the climate change control policy using our revised and updated version of the Emissions Prediction and Policy Analysis (EPPA) model. In addition we amended our methane abatement curves based on different interpretations of estimates that substantial abatement of methane can be obtained at no cost. The inclusion of other greenhouse gases and CO2 sinks reduces the costs of achieving CO2 emissions reductions specified under the agreement. Abstract in HTML and technical report in PDF available on the Massachusetts Institute of Technology Joint Program on the Science and Policy of Global Change Website. (http://mit.edu/globalchange/www/); Includes bibliographical references (p. 7).

Supplementarity : an invitation to monopsony?

2000-04-01T00:00:00Z

Supplementarity : an invitation to monopsony? Article 17 of the Kyoto Protocol allows Annex B parties to meet their commitments by trading greenhouse gas emissions reductions "supplemental" to domestic emissions control. We demonstrate that implementing supplementarity by imposing concrete ceilings on imports of allowances in a market for tradable emissions rights gives rise to monopsonistic effects, even with price-taking behavior by both buyers and sellers. We assess the importance of this finding for Annex B emissions trading, in the context of the import and export provisions of the recent EU Proposal on supplementarity. Our results show that the proposal would reduce efficiency, and could significantly alter the distribution of the gains from trade in an Annex B tradable permits market. Abstract in HTML and technical report in PDF available on the Massachusetts Institute of Technology Joint Program on the Science and Policy of Global Change website (http://mit.edu/globalchange/www/); Includes bibliographical references (p. 16).

A coupled atmosphere-ocean model of intermediate complexity for climate change study

2000-05-01T00:00:00Z

A coupled atmosphere-ocean model of intermediate complexity for climate change study Abstract in HTML and technical report in PDF available on the Massachusetts Institute of Technology Joint Program on the Science and Policy of Global Change website (http://mit.edu/globalchange/www/); Includes bibliographical references (p. 26-28).

Effects of differentiating climate policy by sector : a United States example

2000-05-01T00:00:00Z

Effects of differentiating climate policy by sector : a United States example The experience of other environmental problems suggests that policies yielding uniform marginal costs across sectors, as most analyses assume, are not likely to be realized in practice. Some sectors will be favored over others, yielding different levels of control. Using the MIT Emissions Prediction and Policy Analysis Model, the national cost of such differentiation across sectors is shown to be very high. Moreover, because of interactions and feedbacks in the economy, measures that differentiate in this way may not even aid the sectors they are intended to protect. Abstract in HTML and technical report in PDF available on the Massachusetts Institute of Technology Joint Program on the Science and Policy of Global Change website (http://mit.edu/globalchange/www/); Includes bibliographical references (p. 15).

Russia's role in the Kyoto Protocol

2003-06-01T00:00:00Z

Russia's role in the Kyoto Protocol Bernard, Alain.; Paltsev, Sergey.; Reilly, John M.; Vielle, Marc.; Viguier, Laurent L. As a result of the allocation of emissions reductions, and the differential willingness of countries to ratify, it turns out that Russia is a central player in the Kyoto Protocol. With the U.S. out and Japan and the EU ratifying, the Protocol cannot enter into force without Russian ratification. In part, U.S. rejection of the Kyoto Protocol resulted from the fact that, had the U.S. been in, its least costly road to implementation would have involved large purchases of emissions credits from Russia. With the U.S. out, Russian credits are worth much less but Russia may be able to exploit monopoly power to increase the value of those permits, or Russia could bank permits on the expectation that prices will rise in the future, perhaps as a result of the U.S. reentry into the Protocol in later periods. The Russian decision is more complex, however, in that it is also a major fossil fuel exporter. To the extent it withholds permits from the market, fossil energy prices are depressed further, and the value of its exports of energy are reduced. Thus, Russia faces a tradeoff between maximizing its permit revenue and its revenue from fossil energy exports. We develop this problem as a simple dynamic optimization problem and calibrate the model to the results of two CGE models (EPPA and GEMINI-E3) that fully capture interactions of energy trade, permit trade, and permit and energy prices. We show that carbon prices are relatively insensitive to Russia's behaviors when the U.S. is assumed to participate. It also shows that, in the absence of U.S. participation, the impact of market power by Russia and Ukraine is largely dependent on the elasticity of demand for permits. Finally, we focus on the uncertainty about the supply of CDM by developing countries. It is shown that permit prices are relatively insensitive to CDM supply in the short run but not in the long run. Abstract in HTML and technical report in PDF available on the Massachusetts Institute of Technology Joint Program on the Science and Policy of Global Change website (http://mit.edu/globalchange/www/).

Constraining climate model properties using optimal fingerprint detection methods

2000-05-01T00:00:00Z

Constraining climate model properties using optimal fingerprint detection methods We present a method for constraining key properties of the climate system that are important for climate prediction (climate sensitivity and rate of heat penetration into the deep ocean) by comparing a model's response to known forcings over the 20th century against climate observations for that period. We use the MIT 2D climate model in conjunction with results from the Hadley Centre's coupled atmosphere-ocean general circulation model (AOGCM) to determine these constraints. The MIT 2D model is a zonally-averaged version of a 3D GCM which can accurately reproduce the global-mean transient response of coupled AOGCMs through appropriate choices of the climate sensitivity and the effective rate of diffusion of heat into the deep ocean. Vertical patterns of zonal mean temperature change through the troposphere and lower stratosphere also compare favorably with those generated by 3-D GCMs. We compare the height-latitude pattern of temperature changes as simulated by the MIT 2D model with observed changes, using optimal fingerprint detection statistics. Interpreted in terms of a linear regression model as in Allen and Tett (1998), this approach yields an objective measure of model-observation goodness-of-fit (via the normalized residual sum of squares). The MIT model permits one to systematically vary the model's climate sensitivity (by varying the strength of the cloud feedback) and rate of mixing of heat into the deep ocean and determine how the goodness-of-fit with observations depends on these factors. This approach provides an efficient framework for interpreting detection and attribution results in physical terms. For the aerosol forcing set in the middle of the IPCC range, two sets of model parameters are rejected as being implausible when the model response is compared with observations. The first set corresponds to high climate sensitivity and low heat uptake by the deep ocean. The second set corresponds to low sensitivities for all values of heat uptake. These results demonstrate that fingerprint patterns must be carefully chosen, if their detection is to reduce the uncertainty of physically important model parameters which affect projections of climate change. Abstract in HTML and technical report in PDF available on the Massachusetts Institute of Technology Joint Program on the Science and Policy of Global Change website (http://mit.edu/globalchange/www/); Includes bibliographical references (p. 28-31).

Linking local air pollution to global chemistry and climate

2000-06-01T00:00:00Z

Linking local air pollution to global chemistry and climate We have incorporated a reduced-form urban air chemistry model in MIT's 2D-LO coupled chemistry-climate model. The computationally efficient reduced-form urban model is derived from the California Institute of Technology-Carnegie Institute of Technology (at Carnegie Mellon University) Urban Airshed Model by employing the probabilistic collocation method. To study the impact of urban air pollution on global chemistry and climate we carried out three simulations each including or excluding the reduced-form urban model for the time period from 1977 to 2100. In all three runs we use identical emissions, however in the two runs involving the reduced-form urban model the emissions assigned to urban areas are allocated in different ways depending on the scenario we assume for the future development of polluted urban areas. These two simulations are compared to the reference, which does not utilize the reduced-form urban model. We find that the incorporation of the urban air chemistry processes leads to lower global tropospheric NOx, ozone, and OH concentrations, but to a higher methane mole fraction than in the reference. The tropospheric mole fraction of CO is altered either up or down depending on the projections of urban emissions. The global mean surface temperature is effected very little by the implementation of the reduced-form urban model because predicted increases in CH4 are offset in part by decreases in O3 leading to only small changes in overall radiative forcing. Abstract in HTML and technical report in PDF available on the Massachusetts Institute of Technology Joint Program on the Science and Policy of Global Change website (http://mit.edu/globalchange/www/); Includes bibliographical references (p. 26-29).

The effects of changing consumption patterns on the costs of emission restrictions

2000-08-01T00:00:00Z

The effects of changing consumption patterns on the costs of emission restrictions Includes bibliographical references (p. 14).; Abstract in HTML and technical report in PDF available on the Massachusetts Institute of Technology Joint Program on the Science and Policy of Global Change website (http://mit.edu/globalchange/www/)

Rethinking the Kyoto emission targets

2000-08-01T00:00:00Z

Rethinking the Kyoto emission targets Includes bibliographical references (p. 16).; Abstract in HTML and technical report in PDF available on the Massachusetts Institute of Technology Joint Program on the Science and Policy of Global Change website (http://mit.edu/globalchange/www/)

Fair trade and harmonization of climate change policies in Europe

2000-09-01T00:00:00Z

Fair trade and harmonization of climate change policies in Europe In March 2000, the European Commission presented a Green Paper on greenhouse gas emissions trading within Europe, supporting implementation of a Community-wide scheme in which the design and regulation of all essential elements would be harmonized at the Community level. The present paper analyzes economic arguments used to justify such a coordinated scenario, showing these arguments to be based on misleading rhetoric about fair trade and harmonization. Diverse allocations of emissions allowances across Member States are justified in theory. In practice, too, no empirical evidence or model-based results demonstrate that an uncoordinated European trading scheme would adversely affect competitiveness to any significant extent or substantially increase industrial relocations. Includes bibliographical references (p. 9-11).; Abstract in HTML and technical report in PDF available on the Massachusetts Institute of Technology Joint Program on the Science and Policy of Global Change website (http://mit.edu/globalchange/www/)

The curious role of "learning" in climate policy : should we wait for more data?

2000-10-01T00:00:00Z

The curious role of "learning" in climate policy : should we wait for more data? Given the large uncertainties regarding potential damages from climate change and the significant but also uncertain costs of reducing greenhouse emissions, the debate over a policy response is often framed as a choice of either acting now or waiting until the uncertainty is reduced. Implicit behind the "wait to learn" argument is the notion that the ability to learn in the future necessarily implies that less restrictive policies should be chosen in the near-term. I demonstrate in the general case that the ability to learn in the future can lead to either less restrictive or more restrictive policies today. I also show that the initial decision made under uncertainty will be affected by future learning only if the actions taken today change the marginal costs or marginal damages in the future. Without this interaction, learning has no effect on what we do today, regardless of what we learn in the future. Results from an intermediate-scale integrated model of climate and economics indicate that the choice of current emissions restrictions is independent of whether or not uncertainty is resolved before future decisions, because the cross-period interactions in the model are minimal. Indeed, most climate and economic models fail to capture potentially important cross-period interaction effects. I construct a simple example to show that with stronger interactions, the effect of learning on initial period decisions can be more important. Includes bibliographical references (p. 21).; Abstract in HTML and technical report in PDF available on the Massachusetts Institute of Technology Joint Program on the Science and Policy of Global Change website (http://mit.edu/globalchange/www/)

How to think about human influence on climate

2000-10-01T00:00:00Z

How to think about human influence on climate We present a pedagogical paper on the detection of climate change and its attribution to anthropogenic influences. We attempt to separate the key thought processes and tools that are used when making qualitative statements about the level of human influence on climate. Includes bibliographical references (p. 9).; Abstract in HTML and technical report in PDF available on the Massachusetts Institute of Technology Joint Program on the Science and Policy of Global Change website (http://mit.edu/globalchange/www/)

Tradable permits for greenhouse gas emissions : a primer with particular reference to Europe

2000-11-01T00:00:00Z

Tradable permits for greenhouse gas emissions : a primer with particular reference to Europe This paper is written as part of a two-year study of climate change policy choices facing Sweden, conducted under the auspices of the Center for Business and Policy Studies in Stockholm. As such, it aims to be a primer on emissions trading as an instrument for limiting greenhouse gas (GHG) emissions under the Kyoto Protocol to the Framework Convention on Climate Change. The first section notes general considerations concerning emissions trading, particularly in relation to climate policy. The second section explains the many forms of emissions trading included in the Kyoto Protocol. The third section provides a brief review of emissions trading proposals that have been advanced in Europe as of mid-2000. The fourth section addresses issues in the design and implementation of a national GHG emissions trading system. The brief conclusion is followed by an appendix, which draws applicable lessons concerning the choice and design of a cap and trade system from the U.S. SO2 emissions trading program. Abstract in HTML and technical report in PDF available on the Massachusetts Institute of Technology Joint Program on the Science and Policy of Global Change website (http://mit.edu/globalchange/www/); Includes bibliographical references (p. 38-39).

Carbon emissions and the Kyoto commitment in the European Union

2001-02-01T00:00:00Z

Carbon emissions and the Kyoto commitment in the European Union We estimate reference CO₂ emission projections in the European Union, and quantify the economic impacts of the Kyoto commitment on Member States. We consider the case where each EU member individually meets a CO₂ emissions target, applying a country-wide cap and trade system to meet the target but without trade among countries. We use a version of the MIT Emissions Prediction and Policy Analysis (EPPA) model, here disaggregated to separately include 9 European Community countries and commercial and household transportation sectors. We compare our results with that of four energy-economic models that have provided detailed analyses of European climate change policy. In the absence of specific additional climate policy measures, the EPPA reference projections of carbon emissions increase by 14% from 1990 levels. The EU-wide target under the Kyoto Protocol to the Framework Convention on Climate Change is a reduction in emissions to 8% below 1990 levels. EPPA emissions projections are similar to other recent modeling results but there are underlying differences in energy and carbon intensities among the projections. If EU countries were to individually meet the EU allocation of the Community-wide carbon cap specified in the Kyoto Protocol, we find using EPPA that carbon prices vary from $91 in the United Kingdom to $385 in Denmark; welfare costs range from 0.6 to 5%. Includes bibliographical references (p. 30-32).; Abstract in HTML and technical report in PDF available on the Massachusetts Institute of Technology Joint Program on the Science and Policy of Global Change website (http://mit.edu/globalchange/www/)

The MIT Emissions Prediction and Policy Analysis (EPPA) model : revisions, sensitivities, and comparisons of results

2001-02-01T00:00:00Z

The MIT Emissions Prediction and Policy Analysis (EPPA) model : revisions, sensitivities, and comparisons of results The Emissions Prediction and Policy Analysis (EPPA) model is a component of the MIT Integrated Earth Systems Model (IGSM). Here, we provide an overview of the model accessible to a broad audience and present the detailed structure, data, and parameterization of the model for specialists in economic modeling. EPPA projects emissions of most of the climatically important substances emitted as a result of human activities including carbon dioxide (CO₂), carbon monoxide (CO), methane (CH4), nitrous oxide (N₂O), nitrogen oxides (NOx), hydrofluorocarbons (HFCs), perfluorocarbons (PFCs), sulfur hexafluoride (SF6), sulfate aerosols (SOx), non-methane volatile organic compounds (NMVOCs), black carbon, organic carbon, and ammonia (NH3). We present an updated and consistent inventory for 1995 of all of these emissions disaggregated to the regional and sectoral levels we use in EPPA. This more complete inventory of climatically important substances shows non-energy sources (e.g. agriculture, biomass burning) and developing countries to be important current sources of many of these emissions. A major use of EPPA, a computable general equilibrium model of the world economy with regional and sectoral detail, is to estimate the cost of greenhouse gas emissions control over the 100-year horizon of the model. Reference projections show rates of improvement in energy use per unit of output (Gross Domestic Product) consistent with historical rates although in EPPA we do not attempt to model short-term business cycle behavior so that our projections do not show the same variability as the historical data. Emissions of climatically important substances mostly grow over time in our reference projection (although rates differ substantially among them) despite considerable improvements in energy efficiency and reductions in emissions coefficients for other substances. Developing countries as group become larger sources of all greenhouse gas emissions than developed or transition economies by the middle of the century as their economies and populations are projected to grow more rapidly. There remain many uncertainties in projections of this type. The projections presented in this report are a starting point (i.e. reference) for evaluating alternative scenarios and climate policies. Includes bibliographical references (p. 84-90).; Abstract in HTML and technical report in PDF available on the Massachusetts Institute of Technology Joint Program on the Science and Policy of Global Change website (http://mit.edu/globalchange/www/)

Thermohaline circulation stability : a box model study. Part I: Uncoupled model. Part II: Coupled atmosphere-ocean model

2003-06-01T00:00:00Z

Thermohaline circulation stability : a box model study. Part I: Uncoupled model. Part II: Coupled atmosphere-ocean model Lucarini, Valerio.; Stone, Peter H. Abstract in HTML and technical report in PDF available on the Massachusetts Institute of Technology Joint Program on the Science and Policy of Global Change website (http://mit.edu/globalchange/www/).

Cap and trade policies in the presence of monopoly and distortionary taxation

2001-03-01T00:00:00Z

Cap and trade policies in the presence of monopoly and distortionary taxation We extend an analytical general equilibrium model of environmental policy with pre-existing labor tax distortions to include pre-existing monopoly power as well. We show that the existence of monopoly power has two offsetting effects on welfare. First, the environmental policy reduces monopoly profits, and the negative effect on income increases labor supply in a way that partially offsets the pre-existing labor supply distortion. Second, environmental policy raises prices, so interaction with the pre-existing monopoly distortion further exacerbates the labor supply distortion. This second effect is larger, for reasonable parameter values, so the existence of monopoly reduces the welfare gain (or increases the loss) from environmental restrictions. Abstract in HTML and technical report in PDF available on the Massachusetts Institute of Technology Joint Program on the Science and Policy of Global Change Website. (http://mit.edu/globalchange/www/); Includes bibliographical references (p. 17-19).

The welfare costs of hybrid carbon policies in the European Union

2001-06-01T00:00:00Z

The welfare costs of hybrid carbon policies in the European Union To what extent do the welfare costs associated with the implementation of the Burden Sharing Agreement in the European Union depend on sectoral allocation of emissions rights? What are the prospects for strategic climate policy to favor domestic production? This paper attempts to answer those questions using a CGE model featuring a detailed representation of the European economies. First, numerical simulations show that equalizing marginal abatement costs across domestic sectors greatly reduces the burden of the emissions constraint but also that other allocations may be preferable for some countries because of pre-existing tax distortions. Second, we show that the effect of a single country's attempt to undertake a strategic policy to limit impacts on its domestic energy-intensive industries has mixed effects. Exempting energy-intensive industries from the reduction program is a costly solution to maintain the international competitiveness of these industries; a tax-cum-subsidy approach is shown to be better than exemption policy to sustain exports. The welfare impact either policy -- exemption or subsidy -- on other European countries is likely to be small because of general equilibrium effects. Abstract in HTML and technical report in PDF available on the Massachusetts Institute of Technology Joint Program on the Science and Policy of Global Change website (http://mit.edu/globalchange/www/); Includes bibliographical references (p. 17-18).

Feedbacks affecting the response of the thermohaline circulation to increasing CO₂: a study with a model of intermediate complexity

2001-07-01T00:00:00Z

Feedbacks affecting the response of the thermohaline circulation to increasing CO₂: a study with a model of intermediate complexity Abstract in HTML and technical report in PDF available on the Massachusetts Institute of Technology Joint Program on the Science and Policy of Global Change website (http://mit.edu/globalchange/www/); Includes bibliographical references (p. 31).

CO₂ abatement by multi-fueled electric utilities: an analysis based on Japanese data

2001-07-01T00:00:00Z

CO₂ abatement by multi-fueled electric utilities: an analysis based on Japanese data Multi-fueled electric utilities are commonly seen as offering relatively greater opportunities for reasonably priced carbon abatement through changes in the dispatch of generating units from capacity using high emission fuels, coal or oil, to capacity using lower emitting fuels, natural gas (LNG) or nuclear. This paper examines the potential for such abatement using Japanese electric utilities as an example. We show that the potential for abatement through re-dispatch is determined chiefly by the amount of unused capacity combining low emissions and low operating cost, which is typically not great. Considerably more abatement potential lies in changing planned, base load, fossil-fuel fired capacity additions to nuclear capacity. Our results are at odds with the common view that the demand for natural gas or LNG would increase, or at least not fall, as the result of a carbon constraint; and our analysis suggests that this result may not be limited to Japan. Abstract in HTML and technical report in PDF available on the Massachusetts Institute of Technology Joint Program on the Science and Policy of Global Change website (http://mit.edu/globalchange/www/); Includes bibliographical references (p. 31).

Comparing greenhouse gasses

2001-07-01T00:00:00Z

Comparing greenhouse gasses Controlling multiple substances that jointly contribute to climate warming requires some method to compare the effects of the different gases because the physical properties (radiative effects, and persistence in the atmosphere) of the greenhouse gases are very different. We cast such indices as the solution to a dynamic, general equilibrium cost-benefit problem where the correct indices are the relative shadow values of control on the various substances. We find that use of declining discount rate, as recommended by recent research, suggests that the current physical-based indices adopted in international negotiations overestimate the value of control of short-lived gases and underestimates the value of control of very long-lived species. Moreover, we show that such indices will likely need to be revised over time and this will require attention to the process by which decisions are made to revise them and how revisions are announced. Includes bibliographical references (p. 18-19).; Abstract in HTML and technical report in PDF available on the Massachusetts Institute of Technology Joint Program on the Science and Policy of Global Change website (http://mit.edu/globalchange/www/)

Quantifying uncertainties in climate system properties using recent climate observations

2001-07-01T00:00:00Z

Quantifying uncertainties in climate system properties using recent climate observations We apply the optimal fingerprint detection algorithm to three independent diagnostics of the recent climate record and derive joint probability density distributions for three uncertain properties of the climate system. The three properties are climate sensitivity, the rate of heat uptake by the deep ocean, and the strength of the net aerosol forcing. Knowing the probability distribution for these properties is essential for quantifying uncertainty in projections of climate change. We briefly describe each diagnostic and indicate its role in constraining these properties. Based on the marginal probability distributions, the 5 to 95% confidence intervals are 1.4 to 7.7K for climate sensitivity and 0.30 to 0.95 W/m^2 for the net aerosol forcing using uniform priors; and 1.3 to 4.2K and 0.26 to 0.88 W/m^2 using an expert prior for climate sensitivity. The oceanic heat uptake is not so well constrained. The uncertainty in the net aerosol forcing in either case is much less than the uncertainty range usually quoted for the indirect aerosol forcing alone. Includes bibliographical references (p. 8-11).; Abstract in HTML and technical report in PDF available on the Massachusetts Institute of Technology Joint Program on the Science and Policy of Global Change website (http://mit.edu/globalchange/www/)

Uncertainty in emissions projections for climate models

2001-08-01T00:00:00Z

Uncertainty in emissions projections for climate models Future global climate projections are subject to large uncertainties. Major sources of this uncertainty are projections of anthropogenic emissions. We evaluate the uncertainty in future anthropogenic emissions using a computable general equilibrium model of the world economy. Results are simulated through 2100 for carbon dioxide (CO₂), methane (CH4), nitrous oxide (N₂O), hydrofluorocarbons (HFCs), perfluorocarbons (PFCs) and sulfur hexafluoride (SF6), sulfur dioxide (SO₂), black carbon (BC) and organic carbon (OC), nitrogen oxides (NOx), carbon monoxide (CO), ammonia (NH3) and non-methane volatile organic compounds (NMVOCs). We construct mean and upper and lower 95% emissions scenarios (available from the authors at 1 degree by 1 degree latitude-longitude grid). Using the MIT Integrated Global System Model (IGSM), we find a temperature change range in 2100 of 0.9 to 4.0 degrees C, compared with the Intergovernmental Panel on Climate Change emissions scenarios that result in a range of 1.3 to 3.6 degrees C when simulated through MIT IGSM. Abstract in HTML and technical report in PDF available on the Massachusetts Institute of Technology Joint Program on the Science and Policy of Global Change website (http://mit.edu/globalchange/www/); Includes bibliographical references (p. 23-25).

Uncertainty in atmospheric CO₂ predictions from a parametric uncertainty analysis of a global carbon cycle model

2001-09-01T00:00:00Z

Uncertainty in atmospheric CO₂ predictions from a parametric uncertainty analysis of a global carbon cycle model Key uncertainties in the global carbon cycle are explored with a 2-D model for the oceanic carbon sink. By calibrating the key parameters of this ocean carbon sink model to widely referenced values, it produces an average oceanic carbon sink during the 1980s of 1.94 Pg/yr, consistent with the range estimated by the IPCC of 2.0 Pg/yr +/- 0.8 Pg/yr. A sensitivity analysis of the parameter values used as inputs to the 2-D ocean carbon sink model developed for this study suggests that the IPCC's range for the oceanic carbon sink of 1.2 to 2.8 Pg/yr during the 1980s may be too conservative. By applying the Probabilistic Collocation Method to this simple ocean carbon sink model, the uncertainty in the size of the oceanic sink for carbon and hence future atmospheric CO₂ concentrations is quantitatively examined. An average 1980s oceanic carbon sink of 2.06 ± 0.9 Pg/y (with 67% confidence) is estimated. This uncertainty is found to be dominated the uncertainty in by the rate of vertical mixing of dissolved carbon from the surface into the deep ocean which is parameterized in this study by vertical diffusion. It is observed that a wide range of parameter values can be used to balance the contemporary carbon cycle due to the large uncertainties in the total oceanic and terrestrial sinks. For a reference set of emissions similar to the IS92a scenario of the IPCC, the uncertainty in the atmospheric CO₂ concentration in 2100 is found to be 659 ppm +/- 35 ppm (with 67% confidence). This uncertainty is solely due to uncertainties identified in the "solubility pump" mechanism of the oceanic sink, which is only one of the many large uncertainties lacking a quantitative examination in the global carbon cycle. Such uncertainties have implications for the predictability of atmospheric CO₂ levels, a necessity for gauging the impact of different rates of anthropogenic CO₂ emissions on climate and for policy-making purposes. Because of the negative feedback between the natural carbon uptake by the terrestrial ecosystem and atmospheric CO₂ concentration, taking changes in the former into account leads to a smaller uncertainty in the latter compared to that in the case with the fixed terrestrial uptake. Abstract in HTML and technical report in PDF available on the Massachusetts Institute of Technology Joint Program on the Science and Policy of Global Change website. (http://mit.edu/globalchange/www/); Includes bibliographical references (p. 22-25).

A comparison of the behavior of different AOGCMs in transient climate change experiments

2001-12-01T00:00:00Z

A comparison of the behavior of different AOGCMs in transient climate change experiments The transient response of both surface air temperature and deep ocean temperature to an increasing external forcing strongly depends on climate sensitivity and the rate of the heat mixing into the deep ocean, estimates for both of which have large uncertainty. In this paper we describe a method for estimating rates of oceanic heat uptake for coupled atmosphere/ocean general circulation models from results of transient climate change simulations. For models considered in this study, the estimates vary more than threefold. Nevertheless, values for all models fall in the 5-95% interval of the range implied by the climate record for the last century. The MIT 2D climate model, with an appropriate choice of parameters, matches changes in surface air temperature and sea level rise simulated by different models. It also reproduces the overall range of changes in precipitation. Abstract in HTML and technical report in PDF available on the Massachusetts Institute of Technology Joint Program on the Science and Policy of Global Change Website. (http://mit.edu/globalchange/www/); Includes bibliographical references (p. 12-14).

The evolution of a climate regime: Kyoto to Marrakech

2002-02-01T00:00:00Z

The evolution of a climate regime: Kyoto to Marrakech At meetings in Bonn and Marrakech in 2001, the Conference of the Parties to the Framework Convention on Climate Change broke through an impasse on the detailed provisions needed to allow the Kyoto Protocol to enter into force. Key ingredients in the breakthrough included U.S. withdrawal from the process, an effective relaxation of emissions targets for Japan, Canada, and Russia, and provision of access to unrestricted emissions trading. We analyze the costs of implementation and the environmental effectiveness of the Bonn-Marrakech agreement, and its effect on the relative roles of CO₂ vs. non-CO₂ greenhouse gases. The ability of the major sellers of permits, notably Russia and Ukraine, to restrict access to permits, and the ability to trade across all greenhouse gases controlled under the Protocol, are both found to have a significant effect for both costs and effectiveness. Finally, the implications of the agreement for the future evolution of the climate regime are explored. Abstract in HTML and technical report in PDF available on the Massachusetts Institute of Technology Joint Program on the Science and Policy of Global Change Website. (http://mit.edu/globalchange/www/); Includes bibliographical references (p. 16-17).

Absolute vs. intensity-based emission caps

2003-07-01T00:00:00Z

Absolute vs. intensity-based emission caps Ellerman, A. Denny.; Sue Wing, Ian. Cap-and-trade systems limit emissions to some pre-specified absolute quantity. Intensity-based limits, that restrict emissions to some pre-specified rate relative to input or output, are much more widely used in environmental regulation and have gained attention recently within the context of greenhouse gas (GHG) emissions trading. In this paper we provide a non-technical introduction to the differences between these two forms of emission limits. Our aim is not to advocate either form, but to elucidate the properties of each in a world where future emissions and GDP are not known with certainty. We argue that the two forms have identical effects in a world where future emissions and economic output (i.e., GDP) are known with certainty, and show that outcomes for marginal costs, abatement, emissions and welfare diverge only because of the variance of actual future GDP relative to its forecast expectation. Abstract in HTML and technical report in PDF available on the Massachusetts Institute of Technology Joint Program on the Science and Policy of Global Change website (http://mit.edu/globalchange/www/).

The safety valve and climate policy

2002-02-01T00:00:00Z

The safety valve and climate policy In discussions of a cap-and-trade system for implementation of Kyoto Protocol-type quantity targets, a "safety valve" was proposed where, by government sales of emissions permits at a fixed price, the marginal cost of the effort could be limited to a predetermined level. The advantages seen for such a hybrid system included the shifting of the Kyoto architecture toward a price-based system, and the blunting of opposition to the Protocol on the basis of anticipated high cost. This paper reviews the theoretical underpinnings of the preference for a price instrument for controlling stock pollutants like greenhouse gases, and summarizes the arguments supporting and opposing the safety valve idea within the policy debate. If, in the face of uncertainty, emissions are to be limited to a fixed quantity target, then some means needs to be provided to avoid complete inflexibility. A safety valve can serve this function, although similar advantages can be achieved by the phasing in of quantity targets, coupled with provision for banking and borrowing. Abstract in HTML and technical report in PDF available on the Massachusetts Institute of Technology Joint Program on the Science and Policy of Global Change Website. (http://mit.edu/globalchange/www/); Includes bibliographical references (p. 11).

A modeling study on the climate impacts of black carbon aerosols

2002-03-01T00:00:00Z

A modeling study on the climate impacts of black carbon aerosols The role of black carbon (BC) aerosols in climate change is important because of its strong capability in causing extinction of solar radiation. A three-dimensional interactive aerosol-climate model has been used to study the climatic impact of BC. The interannual variations of BC solar forcing derived from 20-year transient integrations are up to 4 times as large as the means mainly related to changes in cloud cover, snow depth (about +/- 20% over many high- or even mid-latitude regions in Northern Hemisphere) and thus the surface albedo, all caused by BC solar forcing itself. With an absolute amount three times higher than that of the top of the atmosphere (TOA) forcing, the surface forcing of BC is an extremely important factor in analyzing the climate impact of BC. BC aerosols cause a “cloud burning” effect in several polluted regions and a “cloud enhancing” effect in some high-latitude sites. Combined with BC-caused changes in surface albedo, this is defined as a non-Twomey-Albrecht indirect forcing by BC, which alters the radiative budgets by changing cloud cover and some land-surface properties thermodynamically rather than microphysically. The result of this study does not indicate that BC aerosols contribute to a significant increase in land-surface temperature with annual emissions of 14 TgC. The calculated surface temperature change is determined by a subtle balance among changes in surface energy sources and sinks as well as changes in the hydrological cycle, all caused by BC radiative forcing. The result of this study shows that the influence of BC aerosols on climate and environment at the regional scale is more significant than at the global scale. Several important feedbacks between BC radiative effect and climate dynamics revealed in this study suggest the importance of using interactive aerosol-climate models to address the issues related to the climate impacts of aerosols. Abstract in HTML and technical report in PDF available on the Massachusetts Institute of Technology Joint Program on the Science and Policy of Global Change Website. (http://mit.edu/globalchange/www/); Includes bibliographical references (p. 18-19).

Tax distortions and global climate policy

2002-05-01T00:00:00Z

Tax distortions and global climate policy We consider the efficiency implications of policies to reduce global carbon emissions in a world with pre-existing tax distortions. We first show that the weak double dividend, the proposition that the welfare improvement from a tax reform where environme ntal taxes are used to lower distorting taxes must be greater than the welfare improvement from a reform where the environmental taxes are returned in a lump sum fashion, need not hold in a world with multiple distortions. A small analytic general equilib rium model is constructed to demonstrate this result. We then present a large-scale computable general equilibrium model of the world economy with distortionary taxation. We use this model to evaluate a number of policies to reduce carbon emissions. We find that the weak double dividend is not obtained in a number of European countries. Results also demonstrate the point that the interplay between carbon policies and pre-existing taxes can differ markedly across countries. Thus one must be cautious in extrapolating the results from a country specific analysis to other countries. Abstract in HTML and technical report in PDF available on the Massachusetts Institute of Technology Joint Program on the Science and Policy of Global Change Website. (http://mit.edu/globalchange/www/); Includes bibliographical references (p. 17-18).

Incentive-based approaches for mitigating greenhouse gas emissions : issues and prospects for India

2002-06-01T00:00:00Z

Incentive-based approaches for mitigating greenhouse gas emissions : issues and prospects for India As a consequence of the flexibility mechanisms incorporated in the Kyoto Protocol, incentive-based policies such as emissions trading and the clean development mechanism are being widely discussed in the context of greenhouse gas (GHG) abatement. This paper examines various issues related to incentive-based approaches for India. Some of the specific questions it addresses are: does India stand to gain or lose if emissions trading is realized even if it remains outside such an arrangement? Are there any other incentive-based approaches, e.g., carbon taxes that India could adopt? In the ultimate analysis, however, market-based instruments (MBIs) for GHG abatement in India cannot be viewed in isolation from an overall incentive-based orientation towards environmental policy as well as broader economic and legal reform that creates a suitable milieu for MBIs. Therefore, the paper goes on to examine problems of implementing MBIs in general, particularly those related to monitoring of emissions and of enforcement. Several specific solutions are also proposed. Abstract in HTML and technical report in PDF available on the Massachusetts Institute of Technology Joint Program on the Science and Policy of Global Change Website. (http://mit.edu/globalchange/www/); Includes bibliographical references (p. 24-26).

Sensitivities of deep-ocean heat uptake and heat content to surface fluxes and subgrid-scale parameters in an ocean GCM with idealized geometry

2002-09-01T00:00:00Z

Sensitivities of deep-ocean heat uptake and heat content to surface fluxes and subgrid-scale parameters in an ocean GCM with idealized geometry Sensitivities of the net heat flux into the deep-ocean (Qnet) and of the deep-ocean heat content (DOC) below 700 m are studied using an ocean general circulation model and its adjoint. Both are found to have very similar sensitivities. The sensitivity to the surface freshwater flux (E-P-R) is positive in the Atlantic, but negative in the Pacific and Southern Ocean. A positive sensitivity to the downward net surface heat flux is found only in the North Atlantic north of 40 degrees N and the Southern Ocean. The diapycnal diffusivity of temperature affects Qnet and DOC positively in a large area of the tropics and subtropics in both the Pacific and Atlantic Ocean. The isopycnal diffusivity contributes to Qnet and DOC mainly in the Southern Ocean. Detailed analysis indicates that the surface freshwater flux affects Qnet and DOC by changing vertical velocity, temperature stratification, and overturning circulation. The downward net surface heat flux appears to increase Qnet and DOC by strengthening vertical advection and isopycnal mixing. The contribution of isopycnal diffusivity to Qnet and DOC is largely associated with the vertical heat flux due to isopycnal mixing. Similarly, the diapycnal diffusivity of temperature modulates Qnet and DOC through the downward heat flux due to diapycnal diffusion. The uncertainties of Qnet and DOC are estimated based on the sensitivities and error bars of observed surface forcing and oceanic diffusivities. For DOC, they are about 0.7 degrees K (1 degree K = 3 x 10^24 J) for the isopycnal diffusiv ity, 0.4 degrees K for the diapycnal diffusivity of temperature, 0.3 degrees K for the surface freshwater flux, and 0.1 degrees K for the net surface heat flux and zonal wind stress. Our results suggest that the heat uptake by ocean GCMs in climate experiments is sensitive to the isopycnal diffusivity as well to the diapycnal thermal diffusivity. Abstract in HTML and technical report in PDF available on the Massachusetts Institute of Technology Joint Program on the Science and Policy of Global Change Website. (http://mit.edu/globalchange/www/); Includes bibliographical references (p. 25-30).

The deep-ocean heat uptake in transient climate change

2002-09-01T00:00:00Z

The deep-ocean heat uptake in transient climate change The deep-ocean heat uptake (DOHU) in transient climate changes is studied using an ocean general circulation model (OGCM) and its adjoint. The model configuration consists of idealized Pacific and Atlantic basins. The model is forced with the anomalies of surface heat and freshwater fluxes from a global warming scenario with a coupled model using the same ocean configuration. In the scenario CO₂ concentration increases 1% per year. The heat uptake calculated from the coupled model and from the adjoint are virtually identical, showing that the heat uptake by the OGCM is a linear process. After 70 years the ocean heat uptake is almost evenly distributed within the layers above 200 m, between 200 and 700 m, and below 700 m (about 20 x 10^22 J in each). The effect of anomalous surface fresh water flux on the DOHU is negligible. Analysis of CMIP-2 data for the same global warming scenario shows that qualitatively similar results apply to coupled atmosphere-ocean GCMs. The penetration of surface heat flux to the deep ocean in our OGCM occurs mainly in the North Atlantic and the Southern Ocean, since both the sensitivity of DOHU to the surface heat flux and the magnitude of anomalous surface heat flux are large in these two regions. The DOHU relies on the reduction of convection and Gent-McWilliams mixing in the North Atlantic, and the reduction of Gent-McWilliams mixing in the Southern Ocean. Abstract in HTML and technical report in PDF available on the Massachusetts Institute of Technology Joint Program on the Science and Policy of Global Change Website. (http://mit.edu/globalchange/www/); Includes bibliographical references (p. 20-23).

Representing energy technologies in top-down economic models using bottom-up information

2002-10-01T00:00:00Z

Representing energy technologies in top-down economic models using bottom-up information This paper uses bottom-up engineering information as a basis for modeling new technologies within the MIT Emissions Prediction and Policy Analysis (EPPA) model, a computable general equilibrium model of the world economy. Natural gas combined cycle (NGCC) without carbon capture and sequestration (CCS), natural gas combined cycle with CCS, and integrated coal gasification with CCS power generation technologies are introduced into the EPPA model. These compete in the electricity sector with conventional fos sil generation, nuclear, hydro, wind, and biomass power generation. Engineering cost data are used together with EPPA data, including the underlying Social Accounting Matrix (SAM) and supplementary physical energy accounts, to assure that technologies, w h en simulated within the model, meet thermodynamic efficiency limits, and that they reflect regional differences in the cost structure of the electric sector. Alternative capital vintaging approaches are investigated and an explicit treatment of market p enetration of new technologies is developed. Simulations through 2100 show the introduction of the new technologies and their decline as fuel and input prices, and carbon policies, change. A general result is that NGCC plants with or without capture, wh il e currently less costly methods of abating carbon emissions from the electric sector based on engineering data, play only a limited and short-term role in meeting carbon limits. By 2050 the coal CCS plants, currently the most costly of the three techno logies, dominate in the simulated policy scenarios because rising gas prices raise the cost of the gas-based technologies. Abstract in HTML and technical report in PDF available on the Massachusetts Institute of Technology Joint Program on the Science and Policy of Global Change Website. (http://mit.edu/globalchange/www/); Includes bibliographical references (p. 22).

Ozone effects on net primary production and carbon sequestration in the conterminous United States using a biogeochemistry model

2002-11-01T00:00:00Z

Ozone effects on net primary production and carbon sequestration in the conterminous United States using a biogeochemistry model The effects of air pollution on vegetation may provide an important control on the carbon cycle that has not yet been widely considered. Prolonged exposure to high levels of ozone, in particular, has been observed to inhibit photosynthesis by direct cellu lar damage within the leaves and through changes in stomatal conductance. We have incorporated empirical equations derived for trees (hardwoods and pines) and crops into the Terrestrial Ecosystem Model version 4.3 (TEM 4.3) to explore the effects of ozon e on net primary production and carbon sequestration across the conterminous United States. Our results show up to a 5% reduction in Net Primary Production (NPP) in response to modeled historical ozone levels during the late 1980s to early 1990s. The lar ge st decreases (over 20% in some locations) occur in the eastern U.S. and Midwest, during months with high ozone levels and high productivity. Carbon sequestration during the 1980s is reduced by 30 to 70 Tg C/yr with the presence of ozone, or 5 to 23% o f recent estimates of the total carbon sequestration for the U.S. Thus the effects of ozone on NPP and carbon sequestration should be factored into future calculations of the U.S. carbon budget. Abstract in HTML and technical report in PDF available on the Massachusetts Institute of Technology Joint Program on the Science and Policy of Global Change Website. (http://mit.edu/globalchange/www/); Includes bibliographical references (p. 20-21)

Exclusionary manipulation of carbon permit markets: a laboratory test

2002-11-01T00:00:00Z

Exclusionary manipulation of carbon permit markets: a laboratory test The experiment reported here tests the case of so-called exclusionary manipulation of emission permit markets, i.e., when a dominant firm -- here a monopolist -- increases its holding of permits in order to raise its rivals' costs and thereby gain more on a product market. Earlier studies have claimed that this type of market manipulation is likely to substantially reduce the social gains of permit trading and even result in negative gains. The experiment designed here parallels institutional and informat ional conditions likely to hold in real trade with carbon permits among electricity producers. Although the dominant firm withheld supply from the electricity market, the outcome seems to reject the theory of exclusionary manipulation. In later trading p eriods, closing prices on both markets, permit holdings and total electricity production are near competitive levels. Social gains of emissions trading are higher than in earlier studies. Abstract in HTML and technical report in PDF available on the Massachusetts Institute of Technology Joint Program on the Science and Policy of Global Change Website. (http://mit.edu/globalchange/www/); Includes bibliographical references (p. 18-19).

Uncertainty analysis of climate change and policy response

2002-12-01T00:00:00Z

Uncertainty analysis of climate change and policy response To aid climate policy decisions, accurate quantitative descriptions of the uncertainty in climate outcomes under various possible policies are needed. Here, we apply an earth systems model to describe the uncertainty in climate projections under two different policy scenarios. This study illustrates an internally consistent uncertainty analysis of one climate assessment modeling framework, propagating uncertainties in both economic and climate components, and constraining climate parameter uncertainties based on observation. We find that in the absence of greenhouse gas emissions restrictions, there is a one in forty chance that global mean surface temperature change will exceed 4.9 degrees C by the year 2100. A policy case with aggressive emissions reductions over time lowers the temperature change to a one in forty chance of exceeding 3.2 degrees C, thus reducing but not eliminating the chance of substantial warming. Abstract in HTML and technical report in PDF available on the Massachusetts Institute of Technology Joint Program on the Science and Policy of Global Change Website. (http://mit.edu/globalchange/www/); Includes bibliographical references (p. 19-21).

Technology detail in a multi-sector CGE model : transport under climate policy

2003-07-01T00:00:00Z

Technology detail in a multi-sector CGE model : transport under climate policy Schafer, Andreas.; Jacoby, Henry D. A set of three analytical models is used to study the imbedding of specific transport technologies within a multi-sector, multi-region evaluation of constraints on greenhouse emissions. Key parameters of a computable general equilibrium (CGE) model are set to mimic the behavior of a model of modal splits and a MARKAL model of household and industry transport activities. In simulation mode, the CGE model provides key economic data to an analysis of the details of transport technology under policy restraint. Results focus on the penetration of new automobile technologies into the vehicle market. Abstract in HTML and technical report in PDF available on the Massachusetts Institute of Technology Joint Program on the Science and Policy of Global Change website (http://mit.edu/globalchange/www/).