The United States Supreme Court has issued its eagerly-anticipated climate change decision in Massachusetts v. EPA, 549 U.S. ___(2007). In a controversial 5 to 4 decision, the Court has handed a significant victory to Massachusetts, holding:

1. that the states have standing to challenge the U.S. EPA’s decision to not regulate

greenhouse gases;

2. that greenhouse gases are air pollutants under the Clean Air Act; and

3. that the EPA can choose to not regulate greenhouse gases only if the agency’s reasons are

grounded in the text of the Clean Air Act—suggesting this would mean finding that greenhouse gases are not causing climate change.