This article provides a retrospective assessment of the United Nations climate change regime at age thirty. It begins by reviewing the four key stages in the development of the regime. It then discusses how, despite considerable changes in the world, the climate change regime has stayed much the same, and analyzes why the issue has been so intractable. It introduces three models of how international law might address the climate change problem—a prescriptive, contractual, and facilitative/catalytic model—and argues that the facilitative/catalytic approach reflected in the Paris Agreement is best suited to address the climate change problem. It concludes with a report card on how the regime is doing on its 30^th anniversary.