The Intergovernmental Panel on Climate Change (IPCC) is a global organization established to collect and assess the scientific literature related to climate change and its environmental and socioeconomic impacts. The United Nations Environmental Programme and the World Meteorological Organization established the IPCC in 1988. It periodically releases an update on the global state of climate knowledge, most recently the Fifth Assessment Report (AR5). The previous report, AR4, was released in 2007.
The updated AR5 strengthens our understanding of the causes and impacts of climate change. It consists of three working grouns: The first report, Working Group I (or WGI) covered the physical science of climate change. A second report, Working Group II (WGII) covered the impacts of climate change on humans, and identified vulnerabilities and adaptations. The third report, Working Group III, discussed options for mitigating climate change in the context of climate projections.
All three working groups consist of a set of chapters accompanied by a Summary for Policymakers (SPM). The SPM is painstakingly approved by the scientists as well as representatives from all participating nations. By necessity it does not include all of the information in the underlying chapters, but it is carefully crafted to reflect where the balance of the evidence lies. Because of this consensus process, the IPCC is often seen as a conservative body whose reports represent the baseline of climate knowledge.