Justice Ruth Bader Ginsburg, writing for the court, said the plaintiffs were making their case in the wrong forum. Under the Clean Air Act, she wrote, the matter must be addressed by the Environmental Protection Agency rather than the courts.
The lawsuit was filed in 2004 against a different regulatory backdrop. In those days, the Bush administration argued that the Clean Air Act did not permit the agency to issue regulations addressing climate change, and that it would be unwise to do so in any event.
But in 2007, the Supreme Court ruled that the law did authorize federal regulation of greenhouse gas emissions, and that the agency was required to issue them unless it had a scientific basis for its refusal.
After that decision and the change in administrations, the agency has begun to issue greenhouse gas regulations, starting with rules covering automobiles. It is working on more, including one that would set limits on power plants that burn fossil fuels such as coal or natural gas.
It followed, Ginsburg wrote, that the agency rather than the courts should take the leading role in considering limits on power plant emissions, although the agency’s action or inaction would remain subject to judicial review.
Originally, eight states — California, Connecticut, Iowa, New Jersey, New York, Rhode Island, Vermont, and Wisconsin — filed the suit, but New Jersey and Wisconsin later dropped out.
The states and their allies asked the courts to protect them from what they called a public nuisance: the many unwanted consequences of global climate change caused by heat-trapping pollutants. The defendants, they said, were collectively responsible for 25 percent of all greenhouse gas emissions from domestic power plants and 10 percent of emissions from all human activity in the United States.
The private defendants in the suit are American Electric Power Co. of Ohio; Cinergy Co., now part of Duke Energy Corp. of North Carolina; Southern Co. Inc. of Georgia; and Xcel Energy Inc. of Minnesota.
