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Carbon dioxide emitted from tailpipes contributes to global warming. The Supreme Court will decide whether that makes it a pollutant that EPA should regulate.

Supreme Court to Tackle Warming

Eli is a contributing correspondent for Science magazine.

In its first-ever foray into the contentious policy debate over climate, the Supreme Court today agreed to hear arguments on whether the Clean Air Act requires the government to regulate carbon dioxide from cars.

The decision by the High Court is the latest chapter in a 3-year battle between the Bush Administration and a group of states allied with nonprofit groups. In 1999, the Environmental Protection Agency (EPA) under President Bill Clinton ruled that carbon dioxide was a pollutant. The Bush Administration reversed that decision in 2003, and thirteen states then sued EPA.

Last year, a sharply divided appeals court rejected arguments by the states to force EPA to act. This fall, the Supreme Court will address Congress's intent for the 1970 Clean Air Act and subsequent amendments when it hears arguments in Massachusetts v. EPA. The states maintain that the agency must regulate C02 because the act mentions "climate" as an aspect of the environment requiring protection. EPA says that the act "read as a whole," along with Congress's subsequent failure to regulate carbon, means that carbon should not be regulated.

Science has played a central role in the lawsuit. EPA has cited incomplete knowledge on the health impacts of climate change, and in rejecting the states' arguments, one of the appellate judges last year ruled that EPA should use required "judgment" to weigh various other uncertainties surrounding climate change. But last month, in a filing to the High Court, a group of climate scientists including Nobelist Sherwood Rowland of the University of California, Irvine, and James Hansen of NASA's Goddard Institute for Space Studies in New York City asserted that carbon emissions from human activity are "likely or very likely" causing global climate change.

Proponents of regulating carbon hope the case will kick-start their cause. "The Supreme Court taking jurisdiction in this case gives the science community an opportunity to make clear what the science says about climate change," says John Dernbach of Widener University School of Law in Harrisburg, Pennsylvania. But those on the government side, such as Myron Ebell of the conservative Competitive Enterprise Institute in Washington, D.C., are confident that even if they lose this case, they'll win in Congress or through the regulatory comment process. A decision is expected in 2007.

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Posted in Earth, Policy