The Supreme Court's Climate Change Decision: Massachusetts v. EPA

On April 2, 2007, the Supreme Court handed down Massachusetts v. EPA, its first pronouncement on climate change. By 5-4, the Court held the following 1 Massachusetts had standing to sue, 2 Section 202 of the Clean Air Act authorizes the Environmental Protection Agency EPA to regulate emissions from new motor vehicles on the basis of their possible climate change impacts, and 3 Section 202 does not authorize EPA to inject policy considerations into its decision whether to so regulate. The Courts decision leaves EPA with three options under Section 202 find that motor vehicle greenhouse gas emissions may endanger public health or welfare and issue emission standards, find that they do not satisfy that prerequisite, or decide that climate change science is so uncertain as to preclude making a finding either way. The decision also has implications for other climate-change-related litigation, particularly a pending suit seeking to compel EPA regulation of greenhouse gas emissions from stationary sources of emissions.