Federal Agency Actions Following the Supreme Court's Climate Change Decision: A Chronology

Summary

This report presents a chronology of major federal agency actions taken in the wake of Massachusetts v. EPA. In Massachusetts v. EPA, the Court held that greenhouse gases (GHGs), widely viewed as contributing to climate change, constitute "air pollutants" as that phrase is used in the Clean Air Act (CAA). As a result, said the Court, the U.S. Environmental Protection Agency (EPA) had improperly denied a petition seeking CAA regulation of GHGs from new motor vehicles by saying the agency lacked authority over such emissions.