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13 March, 2026
The American Meteorological Society and the scientific societies listed below are surprised and concerned with the decision by the Federal Judiciary Center (FJC) to remove the climate science chapter from the Reference Manual on Scientific Evidence, Fourth Edition and the subsequent letter of February 19, 2026 from 21 attorneys general to the National Academies of Sciences, Engineering, and Medicine (NASEM).
We are surprised because the climate science chapter from the Reference Manual on Scientific Evidence, Fourth Edition, is consistent with all other comprehensive, robust, and rigorous assessments of the science that we are familiar with. It reflects the broad scientific conclusions that result from comprehensive evaluations of evidence and that are based on the efforts of thousands of independent scientists[1]. The evidence relating to climate change has been comprehensively assessed hundreds of times by subject matter experts and scientific organizations that are motivated to be scientifically accurate—people and organizations whose credibility increases with scientific accuracy or diminishes with scientific errors.
Therefore, the FJC decision and the subsequent letter appear to us to be at odds with decades of intensive scientific investigation.
We also have two concerns: 1) that removal of the chapter will mean that public officials will not have access to the best available scientific knowledge and understanding with respect to climate change, and 2) that the actions of people in positions of power will discourage scientists from providing public officials with the best available knowledge and understanding.
The nation has long benefited from the independence of the NASEM in providing evidence-based scientific assessments. Maintaining the independence of the advisory process is essential for providing public officials with the best available scientific understanding. Congress and the Executive Branch have consistently supported the independence of the NASEM.
We stand ready to help all public officials access and use the best available scientific understanding with respect to climate change. Here we briefly summarize four broad conclusions that result from a comprehensive assessment of the scientific evidence.
Observed changes in climate are unusual and widespread. They are occurring throughout the world (in each state, all countries, and on all continents), and across a wide range of physical and biological systems (weather patterns; where oceans and coasts meet; the locations where species occur and the timing of species' key life events—migration, flowering, and bud-burst; to name a few).
The global climate changes people are causing are larger and faster than any humanity is known to have experienced for at least ten thousand years[2].
Multiple lines of scientific evidence confirm that people are overwhelmingly responsible for modern global warming. The warming effect of our greenhouse gas emissions is demonstrated through observations, laboratory, field, and computer-based experiments; evidence from past changes in climate on Earth; and the observed role of greenhouse gases on other planets.
Furthermore, the patterns of global climate change occurring cannot be explained by any plausible known combination of other factors alone: the sun, volcanic eruptions, aerosols, changes in land use, or natural variability.
Humanity's success over the last 6,000 years has come with a relatively stable global climate. A stable and primarily beneficial climate is a foundation of life as we know it. There have been variations in local and regional climates over that time. These have often had large impacts on the people affected. This illustrates that even small global climate changes (relative to those that people are causing now) can have big consequences locally and regionally.
Most of what people depend on is tuned to the climate and highly sensitive to climate change. This includes where and how we live, the food we produce, water resources, the goods and services that nature provides to us, and our built infrastructure. For example, climate determines many physical characteristics of the Earth (weather patterns, where land meets ocean, where ice and snow occur; the location, amount, and timing of water flows)[3]. Warming disrupts biological systems: altering species locations; shifting the timing of key life events; and changing the essential goods and services provided to people by natural and managed systems[4].
Harmful consequences of climate change are happening and are effectively certain to get worse as people emit more greenhouse gases. We cannot know how much more greenhouse gas we can emit before triggering highly detrimental consequences to humanity.
The scientific evidence has been assessed comprehensively by independent scientific institutions and independent experts who seek to consider and weigh all evidence based on scientific merit alone. The National Academies of Sciences, Engineering, and Medicine, The American Association for the Advancement of Science, the American Geophysical Union, and AMS all represent many fields of science. All four have examined and validated climate science. What these scientific organizations say about any one field has consequences for their credibility in all other fields. Rigorous, robust, and accurate assessments of scientific evidence for one field (e.g., climate change) enhance credibility and standing. In contrast, scientific errors and inaccuracies in any one area diminish credibility and standing in all other areas of science.
There are individual scientists who are familiar with the evidence but who reach different conclusions. Unusual perspectives and disagreement are important within the scientific process because they can generate alternative plausible explanations, identify needs for additional inquiry, or challenge the thinking of the larger community of subject matter experts. However, scientific assessments that emphasize unusual views are unrepresentative of the larger community of subject matter experts.
We are not aware of any credible scientific organization that has reached broadly contradictory conclusions.
Of course, science is always open to new evidence. If anyone has new scientific evidence that contradicts any of these conclusions, we welcome learning of it. All people should be aware, however, that the comprehensive assessments of evidence have already considered and accounted for that which might support alternate conclusions.
We encourage all public officials, including within the legal system, to seek and value the best available scientific knowledge and understanding on climate change and for any topic related to their public service. We stand ready to help whenever public officials wish to do so, and for any field of science that we know. We also urge all public officials to support efforts to bring the best available scientific understanding into public discourse.
Therefore, we urge reinstatement of the climate science chapter in the FJC version of Reference Manual on Scientific Evidence, Fourth Edition, and retraction of the letter of February 19, 2026.
Scientific societies adopting this statement:
[1] The science of climate change spans dozens of fields and sub-fields within the physical, natural, and social sciences relating to the Earth and environment. These include (but are not limited to) atmospheric physics, atmospheric chemistry, oceanography (physical, chemical, and biological), cryology, glaciology, biology, physiology, biogeography, biogeochemistry, health, and economics, among others. Each of these disciplines has hundreds of practicing scientists—tens of thousands of scientists overall.
[2] D. Kaufman et al., Sci. Data 7, 201 (2020). https://doi.org/10.1038/s41597-020-0530-7
[3] IPCC WG1, AR6: https://www.ipcc.ch/report/ar6/wg1/
[4] IPCC WG2, AR6: https://www.ipcc.ch/report/ar6/wg2/