This is the first of a series of three biennial reviews of research on the subject of climate change. This review is concerned with the UN Intergovernmental Panel on Climate Change (IPCC): its origins and mandate; its disciplinary and geographical expertise; its governance and organizational learning; consensus and its representation of uncertainty; and its wider impact and influence on knowledge production, public discourse and policy development. The research that has been conducted on the IPCC as an institution has come mostly from science and technology studies scholars and a small number of critical social scientists. The IPCC's influence on the construction, mobilization and consumption of climate change knowledge is considerable. The review therefore ends by encouraging geographers of science to turn their research and scholarship to understanding the roles played by the IPCC, and equivalent institutional processes of climate change knowledge assessment, in the contemporary world.