Cars, Trucks, and Climate: EPA Regulation of Greenhouse Gases from Mobile Sources

James E. McCarthy
Specialist in Environmental Policy

Brent D. Yacobucci
Specialist in Energy and Environmental Policy

Although much of the debate on climate legislation has focused on cap-and-trade1 and tax options,2 establishing greenhouse gas controls is not simply a choice between those two alternatives. A third set of options, using the more traditional regulatory approaches of the Clean Air Act (CAA), is available. These regulatory approaches could be modified through new legislation, but unlike a cap-and-trade system or a carbon tax, regulation does not require new congressional action: the ability to limit GHG emissions already exists under various Clean Air Act authorities that Congress has enacted, a point underlined by the Supreme Court in an April 2007 decision, Massachusetts v. EPA.3

Thus, while the 111th Congress and the Administration discussed new legal authority (for capand- trade, carbon tax, and/or targeted emission controls) the Administration, through the Environmental Protection Agency (EPA), has proceeded to exercise existing authority under the Clean Air Act to begin regulation of greenhouse gas emissions.

The agency has taken several steps to regulate GHG emissions. Nevertheless, EPA Administrator Jackson and others in the Administration have made clear that their preference would be for Congress to address the climate issue through new legislation. In an April 2009 press release, for example, the agency stated, “notwithstanding this required regulatory process, both President Obama and Administrator Jackson have repeatedly indicated their preference for comprehensive legislation to address this issue and create the framework for a clean energy economy.”4 Similar statements have been made on several occasions since that time; in the meantime, though, the agency has concluded that current law, including the 2007 Supreme Court decision discussed below, compels the agency to act.

This report focuses on EPA’s recent and potential actions regarding regulation of GHG emissions from mobile sources under Title II of the Clean Air Act. We begin with a brief discussion of the petitions and court action that have led to EPA’s regulatory decisions.


Date of Report: September 1, 2011
Number of Pages: 13
Order Number: R41981
Price: $29.95

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