RCP8.5 Between Planning and Stress Tests

The Trump administration has proposed amending the Fifth U.

S. National Climate Assessment to identify RCP8.5, SSP5-8.5, and equivalent pathways as implausible expected or baseline futures for federal planning. The pathways would remain useful for climate-model experiments, impact analysis, and stress testing, while researchers debate how much uncertainty in climate sensitivity and other Earth-system factors supports retaining them for high-end risk assessment. The proposal has also reopened wider disputes over the assessment’s evidence, citations, scenario framing, and governance.