National Climate Assessment

• 1. Legislative Origins And Mandate

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  The Global Change Research Act of 1990 established the legal framework for the National Climate Assessment. This law required a report to the President and Congress every four years. The mandate integrated findings from the U.S. Global Change Research Program. It analyzed effects on natural environments, agriculture, energy production, land resources, water systems, transportation, human health, social systems, and biological diversity. The federal government produced these reports through thirteen collaborating agencies. Administrative support came from the University Corporation for Atmospheric Research. The National Science Foundation sponsored that corporation. A team of experts coordinated under the program's auspices.

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• 2. Evolution Of Published Reports

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  The first assessment appeared in 2000 with the title Climate Change Impacts on the United States. It contained twenty regional studies involving dozens of scientific experts. Industry representatives and environmental groups participated in those studies. The second report arrived in 2009 titled Global Climate Change Impacts in the United States. That publication sought measures to adapt to climate change. The third report became available to the public on the 6th of May 2014. More than 300 authors contributed to this version. Over 4000 comments were received during the public review period ending the 12th of April 2013. Volume one of the fourth assessment released in October 2017 stated human activities are the dominant cause of observed warming since the mid-20th century. Volume two followed on the 23rd of November 2018. The fifth report published on the 14th of November 2023 completed the series before work halted.

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• 3. Federal Coordination Mechanisms

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  Thirteen federal agencies collaborated to produce these assessments. The list included NOAA, the Department of Agriculture, Commerce, Defense, Energy, Health and Human Services, Interior, State, Transportation, Environmental Protection Agency, NASA, National Science Foundation, Smithsonian Institution, and USAID. One thousand people assisted with the fourth assessment including three hundred leading scientists. Roughly half came from outside government. The U.S. Global Change Research Program coordinated the team. Administrative support for the program was provided by the University Corporation for Atmospheric Research. This corporation received sponsorship from the National Science Foundation. The Global Change Information System serves as a key access point for all reports. It provides coordinated links to products selected by the thirteen member agencies. Scientists, decision makers, and the public use this open-source web-based resource.

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• 4. Advisory Committee Dynamics

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  The National Climate Assessment and Development Advisory Committee formed in December 2010. It consisted of sixty members who oversaw the draft Third NCA report. Richard H. Moss chaired the successor committee established in 2015. That fifteen-member group focused on sustained national climate assessment efforts. The first Trump administration disbanded the advisory committee on the 18th of August 2017. A second committee also faced termination on the 20th of August 2017. NOAA stated that disbanding would not impact completion of the Fourth National Climate Assessment. The Department of Commerce originally established the initial committee under the Federal Advisory Committee Act of 1972. Support came through the National Oceanic and Atmospheric Administration. These committees helped fulfill the legal mandate under the Global Change Research Act.

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• 5. The Fourth Report Controversy

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  Volume two of the fourth assessment released on the 23rd of November 2018. The New York Times reported an attempt to bury the report occurred during the first Trump administration. Officials timed the release for the day after Thanksgiving. Volume one had arrived earlier in October 2017 as the Climate Science Special Report. That volume contained high confidence findings about human-caused warming since 1951. Volume two warned of growing losses to American infrastructure without mitigation efforts. The report emphasized increasing vulnerability of human health and safety. Administrative lead agency status belonged to the National Oceanic and Atmospheric Administration. The timing drew criticism from scientists who viewed it as political interference.

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• 6. Cessation Of Scientific Work

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  Work halted on the 28th of April 2025 when funding was eliminated during the second Trump Administration. All authors, scientists, and contributors scheduled for the sixth assessment were fired that day. The administration canceled a contract with ICF International providing technical consulting. On the 30th of June 2025, the government website hosting all past reports was taken down. Scientists widely criticized a the 29th of July 2025 Energy Department report promoting climate change denial. Prominent climate deniers received government jobs to write that document. It contained an abundance of errors according to scientific consensus. The scope of future reports remained under re-evaluation while experts faced dismissal. The program effectively ceased operations following these administrative actions.

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