The emerging law of climate change is becoming clearer. The U.S. Supreme Court’s series of climate change and other Clean Air Act (CAA) decisions authorize the U.S. Environmental Protection Agency (EPA) to advance its standards-setting process, and provide general deference to EPA’s  implementation of the CAA and other statutory programs. The Court is sending a clear message to the U.S. Court of Appeals for the District of Columbia (D.C.) Circuit, which reviews most of EPA’s final standards, and to other courts, to restrain judicial activism. Likewise, federal and state courts are opening the door for plaintiffs to assert state common law tort remedies.