The Intergovernmental Panel on Climate Change (IPCC) has been influential in the debate over anthropogenic climate change. The IPCC was set up in 1988 under UN auspices to provide an authoritative assessment of results from climate science as an input to policymakers. Thousands of scientists throughout the world have contributed to the IPCC effort. In a series of reports beginning in 1990, culminating in a thorough overview published in 2001, the IPCC assessments have expressed increasing certainty that human activity contributes significantly to global climate change, and that this contribution will increase in the foreseeable future. A new IPCC report will be completed early in 2007.

We survey the history, organization and operation of the IPCC, which has no close analogue in other areas where science impinges on policymaking. Among issues examined are the ways in which the IPCC is perceived by scientists, policymakers, the media and stakeholders. Questions arising include the role of the IPCC in influencing climate research as well as assessing it, the nature of scientific consensus and dissent in areas of active research with strong policy implications, and the outlook for the future of the IPCC.