This article explains the basic elements of climate change law, with a particular focus on those issues that promise to be important for a considerable time as well as the major factors that are driving the development of this law. The emerging law of climate change is being constructed at the intersection of several areas of law, including environmental law, energy law, business law, and international law. Any effort to address climate change also raises issues about the proper role of state and federal governments, as well as their relationship. This article is intended as an introduction to this complex and rapidly changing subject.