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Supreme Court limits the EPA’s power to regulate greenhouse gases

The U.S. Supreme Court said Monday morning that the Environmental Protection Agency overstepped its authority by rewriting the emissions threshold in the Clean Air Act, but the agency will still be allowed to regulate most stationary sources of greenhouse gases, such as power plants.

Justice Antonin Scalia wrote the majority opinion in the 5-4 ruling, saying that only Congress can tweak the emissions threshold. But, the nation’s highest court ruled 7-2 in the portion of the vote that allows the EPA to move forward with regulating greenhouse gas emissions in industries that are already required to obtain permits for other types of emissions.

Scalia’s opinion noted that the ruling allows the EPA to regulate industries that account “for roughly 83% of American stationary-source greenhouse-gas emissions.” The EPA had previously been seeking to regulate 86% of stationary sources – which include power plants and refineries – meaning the ruling only narrows the scope of the agency’s authority by cutting out 3% of stationary sources.

Justices Samuel Alito and Clarence Thomas were the lone dissenting votes on the latter portion, as they do not believe the EPA should have any authority to regulate greenhouse gas emissions.

The case has its roots in the 2007 Supreme Court decision that identified greenhouse gases as pollutants handed the EPA the authority to regulate motor vehicle emissions. In his opinion Monday, Scalia wrote that it is not “unreasonable” to expand the EPA’s regulatory scope. “We are not talking about extending EPA jurisdiction over millions of previously unregulated entities, but about moderately increasing the demands EPA (or a state permitting authority) can make of entities already subject to its regulation,” Scalia wrote.

The EPA’s regulatory plans had been under attack from a host of challengers that included several states and industry groups who have claimed the federal agency and President Obama’s administration have taken the authority granted in 2007 too far. Earlier this month, the EPA and Obama announced a new regulation meant to cut power plants’ carbon emissions by 30% from 2005 levels by 2030 in a plan that is not affected by Monday’s Supreme Court ruling.