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A response from former USGCRP leaders on proposal to revise the Fifth National Climate Assessment

Editor's note: As part of our coverage of how climate experts are responding to the government's plan to amend the Fifth National Climate Assessment, we're publishing in full this comment submitted to the Federal Register by former senior leadership of the U.S. Global Change Research Program. 

The National Climate Assessment is mandated by law in the Global Change Research Act of 1990. That Act established a cross-government coordinating body that was most recently known as the U.S. Global Change Research Program (USGCRP—a consortium of “at least” 14 agencies named in the Act). Among a number of responsibilities assigned to the USGCRP was the publication of a “scientific assessment” which has been known as the National Climate Assessment (NCA). The Act lays out the NCA as follows:

On a periodic basis (not less frequently than every 4 years), the Council, through the Committee, shall prepare and submit to the President and the Congress an assessment which—

  • integrates, evaluates, and interprets the findings of the Program and discusses the scientific uncertainties associated with such findings;
  • analyzes the effects of global change on the natural environment, agriculture, energy production and use, land and water resources, transportation, human health and welfare, human social systems, and biological diversity; and
  • analyzes current trends in global change, both human-induced and natural, and projects major trends for the subsequent 25 to 100 years.

The language above is the verbatim guidance provided to USGCRP by Congress. Since 1990, USGCRP has published five NCAs (note that NCA4 was released by the first Trump administration). In each of those assessments, the NCA was produced by a large team of scientific experts from across the United States, including Federal employees and contractors, academics, and representatives from the private sector. The development, contents, and authors were developed in an open, transparent manner with multiple rounds of public review and comment at all phases of the assessment process.

In the fifth NCA, authors were directed to assess the most recent science in the area of their chapter (generally meaning research published since the previous NCA). They were not told which science to consider (or not), and they were not told which climate modeling scenarios to consider (or not). They were told to use their scientific expertise to evaluate recent advances in our understanding of the observed and projected changes in the Earth’s climate, and the impacts of those changes on the United States.

Their proposed approach was laid out in an annotated outline that was reviewed by the agencies of the USGCRP and was released for public review and comment. At multiple points throughout the development process, drafts were approved by the USGCRP and released for public comment. The penultimate draft underwent independent, external peer review by the National Academy of Sciences. Each instance of public feedback was recorded and the authors responded to each comment. Those comments and responses were previously available on the USGCRP website, which was dismantled under the current administration.

RCP 8.5 (a "representative concentration pathway") is one of a number of possible future scenarios that the worldwide scientific community uses to evaluate potential future climate conditions. 

Scenarios are just that—possible futures. They are not predictions or forecasts. The range of scenarios considered includes options that span the range of plausible futures, ranging from futures that would require drastic and immediate actions to reduce the release of greenhouse gases (e.g., RCP 2.6) as well as options that assume continued or expanded growth of our release of greenhouse gases (e.g., RCP 8.5). The point of these assessments is to provide policy makers and the public with a detailed description of the likely results of current and future policy decisions; as well as to inform decisions regarding investments in the future (e.g., infrastructure). 

The Fifth National Climate Assessment describes the state of climate science as of its time of publication—it does not predict the future, nor does it direct the Federal (or any other level of) government to take any action or policy direction. We strongly encourage readers to review Appendices A1, A2, and A3 of NCA5, which lay out the approach and rationale to develop the assessment, as well as its use of scenarios. 

The current administration has released a Federal Register notice alerting the public to its intention to “clarify the interpretation and Federal use of NCA5 statements, figures, tables, traceable accounts, regional summaries, public summaries, and derivative Federal communications that rely materially on RCP8.5, SSP5-8.5, SRES A2, or analogous high-emissions pathways.” Given that NCA5 was developed over four years, in the most open and transparent manner possible, and externally reviewed by the National Academy of Sciences, it is hard to imagine any objective of the current administration other than to water down the possible future impacts described in NCA5, and thus discourage actions that are needed and recognized in the majority of the world.

On the substance of the matter, NCA5 appropriately characterized the RCP8.5 scenario and assessed the literature that had used RCP8.5 (and other scenarios) in the years leading up to NCA5's publication in 2023. Further, the government's proposed amendment does not make clear how to distinguish between future scenario information that consists solely of emissions information and future scenario information that involves high-end climate outcomes. It would be a disservice to the Nation to imply that high-end rates of future climate change are implausible. That is not the case. We still have to, unfortunately, prepare for high-end future climate change scenarios even if current and future emissions turn out to be lower than those in RCP8.5.

In addition, it is not appropriate or ethical to change the published findings of an individual scientist or a team of scientists to fit the narrative of an agency, a publisher or an administration.

Doing so would constitute falsification of research and a serious breach of scientific integrity.

The authors of NCA5 were commissioned by the USGCRP agencies to prepare the report. The USGCRP agencies accepted the findings of the authors and published the report. We strongly encourage the administration to focus on the next required National Climate Assessment as mandated in the Global Change Research Act (GCRA) of 1990 and follow OMB guidance regarding highly influential scientific reports.

We object strongly to the proposed efforts to revisit the findings of NCA5, and instead encourage the administration to follow the law and past precedent by reconstituting the U.S. Global Change Research Program, and preparing the Sixth National Climate Assessment (which is due in 2027 as per the GCRA) in the open, transparent manner that has been the standard for past National Climate Assessments.

  • Michael Kuperberg, Ph.D., retired—Department of Energy, former Executive Director of USGCRP
  • Virginia Burkett, Ph.D., retired Chief Scientist for Climate and Land Use Change, United States Geological Survey, former Chair of the Subcommittee on Global Change Research
  • Anjuli S. Bamzai, Ph.D., retired Senior Science Advisor, U.S. National Science Foundation 
  • Jack Kaye, Ph.D., retired, Associate Director for Research, Earth Science Division, NASA, Principal to the Subcommittee on Global Change Research
  • Ben DeAngelo, formerly Director, US EPA Office of Climate Adaptation & Sustainability and Deputy Director of USGCRP
  • Philip B. Duffy, Ph.D., Climate Science Advisor, White House Office of Science and Technology Policy (2021 - 2024).

*The above authors are no longer associated with the Federal government and are commenting in their personal capacities.