“The Intergovernmental Panel for Climate Change (IPCC) was established to provide the decision-makers and others interested in climate change with an objective source of information about climate change. The IPCC does not conduct any research nor does it monitor climate related data or parameters. 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”.

The IPCC website is a key resource for Climate Change assessment.

IPCC Fourth Assessment Report: Climate Change 2007

The AR4 Synthesis Report Working Group I Report
"The Physical Science Basis"
Working Group II Report
"Impacts, Adaptation and Vulnerability"
Working Group III Report
"Mitigation of Climate Change"