The Intergovernmental Panel on Climate Change was formed in 1988 by two United Nations organizations, the United Nations Environment Programme and the World Meteorological Organization, to assess the state of scientific knowledge about the human role in climate change.
To accomplish its mission, the IPCC coordinates the efforts of more than 2,000 scientists from 154 countries. Together, they represent a vast array of climate specialties, from physics, to chemistry, to interactions with Earth's surface, to the role of human behavior. Their reports take years of critical assessment and review before they are issued to the public. The scientists who participate volunteer their time to IPCC activities, assisted by a small number of paid staff.
Because each chapter is subjected to more extensive review than perhaps any other scientific report, and because the authors are assessing multiple studies, many of the findings reported by the IPCC are considered more cautious or conservative than the outlooks provided by any single experiment or analysis.
Because different types of expertise are required to assess different aspects of climate change, the IPCC is divided into three working groups.
Each working group prepares a lengthy report and a much briefer "Summary for Policymakers." In addition to the three working groups, the IPCC Task Force on National Greenhouse Gas Inventories was created in 1991 to help participating countries calculate and report their production and elimination of greenhouse gases.
In addition to reviews by individual scientists and scientist panels, each chapter within an assessment is also scrutinized by representatives of the governments participating in the IPCC process. While governments negotiate on how the findings are worded, the final product is based on a scientific, not a political, consensus.
After years of planning, collecting, writing, and responding to multiple reviews, each assessment report reflects the scientific consensus on what is known and what is still uncertain about the environmental and societal consequences of continuing to add greenhouse gases to Earth's atmosphere.
In late 2007, the IPCC shared the Nobel Peace Prize with former U.S. vice president Al Gore for its work in having "created an ever-broader informed consensus about the connection between human activities and global warming." (The prize was awarded to the panel rather than to individual participants.)
The IPCC has published major assessments in 1990, 1996, 2001, and 2007, as well as special interim reports on topics such as aviation, land use, assessment methods, or emissions scenarios. All of the major and interim reports are available in the six official languages of the United Nations and may be downloaded from the IPCC Publications and Data page.
The next major IPCC assessment will be released in several stages in late 2013 and 2014.
IPCC History (United Nations Foundation/IPCCFacts.org)