The Fourth National Climate Assessment was written to help inform decision-makers, utility and natural resource managers, public health officials, emergency planners, and other stakeholders by providing a thorough examination of the effects of climate change on the United States.

A team of more than 300 federal and non-federal experts, including individuals from federal, state, and local governments, tribes and Indigenous communities, national laboratories, universities, and the private sector volunteered to produce the assessment. These experts also had input from external stakeholders at each stage of the process.

Participants included decision-makers from the public and private sectors, resource and environmental managers, scientists, educators, representatives from businesses and nongovernmental organizations, and the interested public.

This resource directs browsers to the products the USGCRP developed. Two major assessment products are The Impacts of Climate Change on Human Health in the United States: A Scientific Assessment and the Second State of the Carbon Cycle Report. In addition, USGCRP agencies contributed products that improve the thoroughness of this assessment, including the U.S. Department of Agriculture’s scientific assessment Climate Change, Global Food Security, and the U.S. Food System; NOAA’s Climate Resilience Toolkit, Climate Explorer, and State Climate Summaries.

USGCRP Scenario Products span a range of possible future changes (through at least 2100) in key environmental parameters. These new scenario products that people use include changes in average and extreme statistics of key climate variables (for example, temperature and precipitation), changes in local sea level rise along the entire U.S. coastline, changes in population as a function of demographic shifts and migration, and changes in land use driven by population changes.

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