Trump administration proposes revisions to how Fifth National Climate Assessment frames worst-case scenarios

The Trump administration has published a notice proposing changes to a Biden-era federal climate report, focusing on how the Fifth National Climate Assessment describes its highest-emission, worst-case scenarios. The proposal is part of an effort to revise a specific portion of the assessment rather than replace the full report, according to the notice described by The Hill.

The notice addresses how the assessment characterizes extreme outcomes under high-emission futures. The Hill reported that the administration is seeking to reframe the report’s “worst-case” depiction after U.N. scientists said earlier this year that a worst-case scenario was not plausible, a premise that the administration says should be reflected in the federal assessment.

The National Climate Assessment is produced through a federal process that brings together scientific and technical information for federal planning and public communication. In the notice, the Trump administration characterized the changes as a way to adjust the assessment’s portrayal of high-emission risk based on updated scientific context, as reported by The Hill.

According to the reporting, the administration is not disputing that climate change impacts are occurring, but is targeting the language used to describe the tail end of potential outcomes. The Hill said the proposal would alter how the assessment’s scenario framing is presented, including the description of the most severe outcomes associated with high-emission pathways.

The proposed changes arrive after years of debate about how federal climate assessments communicate uncertainty and the range of possible future impacts. Critics of prior assessments have often argued that the worst-case language can be misread as a single likely endpoint, while supporters have said such framing is important for risk planning. The Trump administration’s notice, as described by The Hill, centers on the specific scenario depiction and how it is justified in light of the U.N. scientific commentary.

The notice also sets up a public process for response, with the administration’s proposal inviting comments before the assessment is finalized. The practical effect, if adopted, would be a revision to the way the federal report communicates the severity of potential climate outcomes under high-emission conditions, which could shape how agencies reference the assessment in planning, rulemaking, and program design.

No immediate legislative action was described in the reporting. The next step would be the administration’s completion of the review process for the notice and consideration of comments, followed by publication of any final updates to the Fifth National Climate Assessment’s wording in the targeted section.