CRS Issue Statement on Greenhouse Gases: Control and Mitigation

Jane A. Leggett, Coordinator
Specialist in Energy and Environmental Policy


In the 111th Congress, leadership in both chambers have announced priorities to pass bills to reduce U.S. greenhouse gas (GHG) emissions. These intentions are indicative of the pressures Members of Congress increasingly face on whether and how to address human-induced climate change. Contentious debates scrutinize issues of science, economics, values, geopolitics and a host of other concerns. Deliberations also weigh the appropriateness of alternative policy tools and program designs. The economic stakes are potentially large—with both the costs of controls and the "costs of inaction" ranging, by some estimates, into trillions of dollars over several decades. 

In the absence of economy-wide federal legislation aimed at controlling GHG emissions, states and localities have established policies, regulations, and financial incentives. Sometimes these efforts are regionally coordinated, or facilitated through national and international networks. In addition, litigation has proliferated to try to force actions through existing laws. In Massachusetts v. EPA, the Supreme Court held that as to mobile sources of emissions (cars, trucks), EPA has authority under the act to regulate greenhouse gas (GHG) emissions. This decision puts pressure on EPA to move forward as well with regulation of GHGs from stationary sources (power plants, factories). Other suits have been pursued under the Endangered Species Act, the Energy Policy and Conservation Act, the National Environmental Policy Act, and others. Common law tort theories such as nuisance have been invoked, not yet successfully, to force cutbacks in GHG emissions, or payment of damages. Several cases are on appeal. Actions in statehouses and courthouses increase the pressure on Congress to enact an intentional framework to address climate change—both mitigation and adaptation. 

For decision-makers considering climate change legislation, an assortment of policy instruments is available; studies suggest that a combination could be most effective in achieving various climate policy objectives. Current policy attention has focused on "cap and trade" strategies to reduce GHG emissions, with additional policy tools aimed at promoting the technology development considered necessary to slow climate change significantly. In parallel, growing attention is being given to supporting adaptations to expected future changes, as well as to strategies to gain effective international engagement in reducing GHG. One significant obstacle to consensus is concern about the potential costs of abating GHG emissions, since deep reductions would require extraordinary changes in energy use and technologies. Studies suggest that efficiently designed programs could moderate the costs of reducing GHG emissions; technically and politically, though, an "efficiently designed" program may not be realistic. Policy options can ease the adjustments required and modify the distribution of costs—or potential wealth embodied in distribution of emission allowances—across specific sectors or populations. A core challenge of policy design, then, is balancing the climate effectiveness of a policy, the economic costs, and its distributional effects.


Date of Report: January 8, 2010
Number of Pages: 3
Order Number: IS41015
Price: $29.95

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