Fourth National Climate Assessment Vol I + II
NCA4 Vol II: Impacts, Risks, and Adaptation in the United States
NCA4 Vol I: Climate Science Special Report
The Reports Library features scientific assessments, annual reports, strategic research plans, and other resources produced by USGCRP and the collaborative efforts of our member agencies. Select reports by other authoritative scientific bodies with whom we work, such as the Intergovernmental Panel on Climate Change (IPCC) and the National Research Council (NRC), are also accessible here. Most reports are available for download (open and click View); some can be ordered in print free of charge (open and click Add to Cart).
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This report synthesizes the contributions of Working Groups I, II, and III to the IPCC’s Fourth Assessment Report, and also draws on recent IPCC Special Reports. It draws together policy-relevant scientific, technical, and socioeconomic information related to climate change, with the goal of assisting governments and other decision makers in formulating and implementing responses.
This report is the contribution of Working Group I to the IPCC’s Fourth Assessment Report. It provides insights into the effects of human activity on the atmosphere; contains an evaluation of observed climatic changes using the latest measurement techniques; includes a detailed review of climate change observations and modeling for every continent; and features the first probabilistic evaluation of climate model simulations.
The Working Group I contribution to the IPCC’s Fifth Assessment Report (WGI AR5) provides a comprehensive assessment of the physical science basis of climate change.
The Working Group I contribution to the IPCC Fifth Assessment Report (WGI AR5) provides a comprehensive assessment of the physical science basis of climate change. Here, the Working Group I report is summarized for both technical and policy audiences.