In a 5-4 decision, the Supreme Court put regulation of greenhouse gases from cars and carbon dioxide emissions under the control of the EPA.
As reported by AP the court said the states have the right to sue the EPA to challenge its decision and the Clean Air Act does give the EAP the authority to regulate tailpipe emissions of greenhouse gases. With regard to the issue of whether the EPA has the discretion not to regulate emission the court ordered the EPA to re-evaluate its contention it has the discretion not to regulate tailpipe emissions.
"EPA has offered no reasoned explanation for its refusal to decide whether greenhouse gases cause or contribute to climate change," Stevens said. He was joined by his colleagues, Justices Stephen Breyer, Ruth Bader Ginsburg and David Souter, and the court's swing voter, Justice Anthony Kennedy.