Climate change threatens to cause the largest refugee crisis in human history. Millions of people, largely in Africa and Asia, might be forced to leave their homes to seek refuge in other places or countries over the course of the century. Yet the current institutions, organizations, and funding mechanisms are not sufficiently equipped to deal with this looming crisis. The situation calls for new governance. We outline and discuss in this article a blueprint for a global governance architecture for the protection and voluntary resettlement of climate refugees—defined as people who have to leave their habitats because of sudden or gradual alterations in their natural environment related to one of three impacts of climate change: sea-level rise, extreme weather events, and drought and water scarcity. We provide an extensive review of current estimates of likely numbers and probable regions of origin of climate refugees. With a view to existing institutions, we argue against the extension of the definition of refugees under the 1951 Geneva Convention Relating to the Status of Refugees. Key elements of our proposal are, instead, a new legal instrument specifically tailored for the needs of climate refugees—a Protocol on Recognition, Protection, and Resettlement of Climate Refugees to the United Nations Framework Convention on Climate Change—as well as a separate funding mechanism.