Intergovernmental Panel on Climate Change IPPC

The World Meteorological Organization WMO and the United Nations Environment Programme UNEP established the IPCC in 1988 "to provide the decision-makers and others interested in climate change with an objective source of information about climate change... Its role is to assess on a comprehensive, objective, open and transparent basis the latest scientific, technical and socio-economic literature produced worldwide relevant to the understanding of the risk of human-induced climate change, its observed and projected impacts and options for adaptation and mitigation..." Quoted from IPPC Mandate. 

On 12 October 2007 the IPCC and Al Gore were awarded the 2007 Nobel Peace Prize "for their efforts to build up and disseminate greater knowledge about man-made climate change, and to lay the foundations for the measures that are needed to counteract such change". 

IPCC Assessment reports are at the IPCC link.
Working Group II Contribution to the IPCC Fourth Assessment Report AR4
Climate Change 2007: Climate Change, Impacts, Adaption and Vulnerability, draft report.

U.N. Chief Seeks More Climate Change Leadership, Elisabeth Rosenthal, New York Times report, 18 November 2007.

UN panel gives dire warming forecast, Arthur Max, Associated Press, St. Petersburg Times, 17 November 2007.