A striking contradiction has emerged between Beijing’s growing geopolitical isolation on one hand, and its apparent continued commitment to tackling global climate change on the other. The big question, for China and for the world, is whether political and economic decoupling threatens long-term decarbonization. Unfortunately for the planet, the answer is likely yes, at least to some extent. How much will depend in large part on how hard and how lasting China’s inward turn proves to be. To understand how much China’s role in global efforts to address climate change has shifted over the past six months, it is helpful to recall Xi Jinping’s landmark speech to the United Nations General Assembly in September 2020.