Over the past three decades, global climate governance has evolved from a peripheral environmental concern into one of the central pillars of world politics. Since the early 1990s, when the international community first began to institutionalize collective action under the United Nations Framework Convention on Climate Change (UNFCCC), the architecture of global environmental governance has undergone a profound transformation. Amid this transformation, few actors have had a more significant—and at times controversial—impact than the People’s Republic of China. From a cautious participant in the early years of global climate diplomacy to a proactive contributor and, increasingly, a leading architect of governance norms, China’s trajectory epitomizes both the opportunities and the contradictions of governing a shared global common in an age of multipolarity and interdependence.