International Emissions Trading & Global Climate Change: Impacts on the Cost of Greenhouse Gas Mitigation
Prepared for the Pew Center on Global Climate Change
Jae Edmonds, Michael J. Scott, Joseph M. Roop, and Christopher N. MacCracken, Battelle, Washington, DC
Press Release 
Eileen Claussen, President, Pew Center on Global Climate Change
Several factors influence the costs of greenhouse gas mitigation. This report illustrates the importance of one such factor—international emissions trading—in reducing the costs of carbon control. The authors find that an international greenhouse gas emissions trading regime will significantly lower global mitigation costs. Specifically, the report finds:
This report is the first in a series designed to explore how economic models address the climate change issue. The first phase of this effort will make a direct and significant contribution to economic modeling in the following four areas: (1) review of existing models and identification of their key assumptions; (2) investigation of the models’ theoretical frameworks; (3) encouraging best practices in modeling specific aspects of the climate change issue; and (4) integrating innovative modeling practices into a state-of-the-art assessment of the costs of climate change and the policies used to address it.
The second phase of the Pew Center’s economics program will focus on how businesses react to climate change—and policies to ameliorate it—in the context of sound business strategy and practice. The Center is in a unique position to provide insight into the inner working of firms through the participation of our Business Environmental Leadership Council.
The Center and authors appreciate the valuable input of several reviewers of previous drafts of this paper, including Ev Ehrlich, Judi Greenwald, Eric Haites, Elizabeth Malone, and others.
One of the earliest and most robust findings of economics is that, where relative costs of performing an activity differ among individuals, business firms, or regions, there are almost always potential gains from trade. In today’s jargon, trade can always be win-win. Traditional approaches to addressing environmental problems have generally not taken advantage of this potential. Rather, command and control regulatory policy instruments have been the tools of choice. While these tools can be effective in reaching an environmental goal, they can also be expensive. Recently environmental policy-makers have begun to explore ways of obtaining more environmental benefits per dollar expended, and the use of emissions trading has been on the cutting edge of these efforts. Because climate change is an issue that requires a sustained policy commitment over the course of a century, attention to the cost of policy intervention is especially important. This paper explores the degree to which trade among parties to an international agreement can reduce the cost of greenhouse gas reductions.
International trade holds the potential of reducing costs of controlling world emissions of greenhouse gases (GHGs) because the nations of the world experience very different costs for achieving emissions reductions on their own. However, the potential gains from trade, like the costs of compliance themselves, may be very unevenly distributed across the world’s participants. While all of the parties to an agreement stand to gain collectively under trade in emissions rights as compared with "independent compliance" (i.e., each country meeting its obligations alone), non-participants in the agreement may either benefit or not depending on their own particular circumstances. The detailed rules for trading affect how effective trading could be, as well as the level of gains that would be captured in practice. Details of the trading rules will influence both the total gains from trade and distribution of such gains. Key issues include definitions of the emissions rights to be traded, the rules for crediting carbon sinks, and regulations governing participation in the trading framework. In addition, there are economic uncertainties, such as the behavior of countries that have significant market power in supplying emissions credits, and the transaction costs associated with trading and enforcement. These effects could significantly increase the costs of mitigation compared to the most favorable case and could reduce the amount and benefits of trading.
A number of global economic models have been used to estimate the effects of emissions trading. Empirical results derived from these models can be summarized as follows: