On February 24, 2014, the Supreme Court will hear a challenge to EPA’s rules regulating greenhouse gas emissions form stationary sources under the Clean Air Act’s Prevention of Significant Deterioration program. This case comes to Supreme Court as a consolidation of six cases after the D.C. Circuit unanimously upheld portions of the EPA’s greenhouse gas program.

The Court granted certiorari a limited question: whether the EPA permissibly determined that its regulation of greenhouse gas emissions from new motor vehicles triggered permitting requirements under the Clean Air Act for stationary sources that emit greenhouse gases.

This is a blockbuster case and will turn on whether EPA had the authority to regulate greenhouse gases at high thresholds to avoid absurd results. If the Court decides to uphold or curtail EPA’s interpretation, its decision will have sweeping effects on the United States’ efforts to address climate change.