A Hot Debate on Climate Change

The different views among the nine justices on the U.S. Supreme Court about climate change were clearly visible today as the high court tackled the simmering controversy over government regulation of greenhouse gas emissions. Climate research has played a central role in the case, which addresses the degree of scientific uncertainty on global warming and the impacts of rising temperatures.

Commonwealth of Massachusetts et al. v. Environmental Protection Agency has been working its way to the high court since 1999, when a group of nonprofits asked EPA to set greenhouse gas emission standards for motor vehicles under the Clean Air Act. Four years later, the agency said that Congress hadn't given it the legal authority to do so. Even if the agency had such authority, EPA officials added, setting such limits would be premature given ongoing climate studies, debate over likely impacts, and concerns that new rules would interfere with fuel-efficiency laws. Also at issue is whether the states have the right to ask EPA to act. Under the legal principle of standing, parties must be able to show that they are being harmed by the current situation. An appeals court rejected the arguments by a number of states, led by Massachusetts, that impacts such as the loss of coastline from rising sea levels gave them the right to sue. The high court agreed to take the case in June.