Fourth National Climate Assessment

• 1. Legislative Origins And Mandate

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  President George H.W. Bush signed the Global Change Research Act of 1990 into law on the 16th of November 1990. This legislation established the United States Global Change Research Program with a clear mandate to understand and respond to global change. The act required reports to be submitted to Congress every four years starting from that date. The program aimed to promote discussions toward international protocols in global change research. It also sought to address the cumulative effects of human activities and natural processes on the environment. Only four reports have been released since the act was enacted despite the four-year requirement. The Fourth National Climate Assessment marked the first report produced under the Trump administration.

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• 2. Scientific Methodology And Authors

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  The National Oceanic and Atmospheric Administration served as the administrative lead agency for the NCA4 preparation. Thirteen federal agencies comprised the USGCRP team including NASA, NOAA, and the Department of Energy. Over 1,000 people assisted in producing the report during its two-year development period. Roughly half of these contributors were scientists working outside the government. Three hundred leading scientists participated alongside federal employees who formed the Federal Science Steering Committee. Representatives from NOAA, NASA, and DOE sat on this committee along with three Coordinating Lead Authors. All members of the Federal Science Steering Committee held federal employee status throughout the report's creation phase. The Obama administration released a review draft of the Climate Science Special Report with a public comment period running from the 15th of December 2016 through the 3rd of February 2017.

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• 3. Core Climate Findings And Projections

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  Researchers reported that it is extremely likely that human activities are the dominant cause of observed warming since the mid-20th century. No convincing alternative explanation exists supported by the extent of observational evidence for the warming over the last century. Without significant mitigation efforts substantial damages will occur to the U.S. economy, human health, and the environment. Annual losses in some sectors could grow to hundreds of billions of dollars by the end of the century under high emission scenarios. Damages across the United States are intensifying according to the report analysis. Poor and marginalized communities face the most negative impacts from intensifying storms and weather patterns caused by global warming. Risks remain highest for those already vulnerable including low-income communities, children, and the elderly. Climate change threatens to exacerbate existing social and economic inequalities resulting in higher exposure to extreme events.

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• 4. Political Release Timing And Reception

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  The White House announced on November 21 that it would release the NCA4 findings on Black Friday. President Trump told reporters he had seen and read some of the report but stated he does not believe it. White House spokesperson Lindsay Walters dismissed the climate report as largely based on the most extreme scenario. Steven Milloy called the report a product of the deep state and added that they do not care about its contents. The administration chose to release the document the day after Thanksgiving hoping it would get swept away by next days news. Collin O'Mara, President of the National Wildlife Federation, called the timing an absolute disgrace. He noted that authorities were still identifying bodies in California's unprecedented megafires when the report dropped. Articles described the release as a bleak black Friday report while others labeled it a massive grave climate warning.

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• 5. Public Response And Policy Debates

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  An article in The Atlantic said the report warns repeatedly and directly that climate change could soon imperil the American way of life. The Union of Concerned Scientists described how the 1,500-page report was based on the best available science. Brenda Ekwurzel served as both a NCA4 Report Author and Senior UCS Climate Scientist during this period. Andrew Cuomo reconvened a modified version of the science advisory panel chaired by Columbia University's Earth Institute's Richard Moss in January 2018. This states' panel cannot replace federal support for science including maintaining satellites or building better climate models. It will have no sway over federal climate policy despite assisting policymakers and private-sector officials with long-term planning. In May 2019 The New York Times reported that the Trump administration planned to make changes in climate modeling methods used for the next report due in 2022. They intended to project impacts only to 2040 rather than projecting to the end of the century as done previously.

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