Short answers, pulled from the story.
The National Climate Assessment is a federal research initiative mandated by the Global Change Research Act of 1990 that integrates scientific findings on how climate change affects the United States. It is produced by the U.S. Global Change Research Program, a collaboration of 13 federal agencies including NOAA, NASA, the EPA, and the Departments of Agriculture, Defense, Energy, and others.
Five National Climate Assessments have been published as of 2023. The first was released in 2000, followed by reports in 2009, 2014-2017-2018 (in two volumes), and the fifth on the 14th of November 2023. Work on the sixth assessment was halted in 2025.
The Fourth National Climate Assessment's Volume 1, released in October 2017, concluded that it is extremely likely that human activities, especially emissions of greenhouse gases, are the dominant cause of the observed warming since the mid-20th century, and that there is no convincing alternative explanation supported by the observational evidence.
On the 28th of April 2025, the second Trump administration fired all authors, scientists, and contributors working on NCA6, which had been scheduled for release in 2028. Funding was eliminated and a contract with ICF International providing technical consulting was also canceled. The scope of the report was described as being re-evaluated.
On the 30th of June 2025, the government website hosting access to all past National Climate Assessment reports was taken down. In late 2025, the organization climate.us established a separate website to host the Fifth National Climate Assessment outside of government servers.
The Third National Climate Assessment, released publicly in May 2014, was written by more than 300 authors drawn from academia, local, state, tribal, and federal governments, and the private and nonprofit sectors. It also received more than 4,000 public comments from 644 individuals and organizations during its public comment period.