Justices push EPA to act on car emissions

In a 5-4 decision, the high court rebuked the Bush administration and ruled that so-called greenhouse gases -- like carbon dioxide -- were air pollutants subject to federal regulation.

President Bush and his aides, allied with automakers, argued that federal officials did not have the power to set mandatory limits on greenhouse gas emissions.

The court's ruling knocked down a legal barrier that kept California and other states from requiring reduced carbon emissions by new vehicles starting in 2009.

Gov. Arnold Schwarzenegger praised the decision and said he was "very encouraged."

Under the Clean Air Act, California won the right to adopt its own regulations limiting emissions by new vehicles, but only if the Environmental Protection Agency issued a waiver saying the state's rules complied with the law. No waiver has been issued.

Schwarzenegger said he expected the EPA "to move quickly now in granting our request for a waiver, which will allow California and [the] other states that have adopted our standards to set tougher vehicle emissions levels."

Auto industry lawyers have sued in federal court in Fresno, arguing that California's emissions rules conflicted with the Clean Air Act. The case was put on hold, awaiting the Supreme Court decision issued Monday.

"We think this is the end of the automakers' case," said David Bookbinder, a Sierra Club lawyer.

Scientists have linked the rise in greenhouse gas emissions to a steady and potentially catastrophic increase in air temperatures. The administration maintained that the gases were not air pollutants as defined by the Clean Air Act.

The measure, passed in the 1970s, targeted specific pollutants, such as lead.

In its ruling, the Supreme Court agreed that global warming represented a different kind of air pollution problem. Gases such as carbon dioxide, once released into the atmosphere, "act like a ceiling of a greenhouse, trapping solar energy and retarding the escape of reflected heat," the court said.

The majority opinion, written by Justice John Paul Stevens, said that under the Clean Air Act, the EPA was required to regulate the emission of "any air pollutant" that was likely "to endanger public health or welfare."