The Climate Change 2001 volumes of the Third Assessment Report of the IPCC provide the most comprehensive assessment of climate change since its second report, Climate Change 1995. This Synthesis Report provides a policy-relevant, but not policy-prescriptive, synthesis and integration of information contained within the Third Assessment Report and also draws upon all previously approved and accepted IPCC reports that address a broad range of key policy-relevant questions. For this reason it will be especially useful for policy makers and researchers, and as a main or supplementary student textbook for courses in environmental studies, meteorology, climatology, biology, ecology, and atmospheric chemistry.