UN Climate Scenario Committee Retires High-Emissions Pathway

The international scientific committee that designs climate scenarios for the United Nations retired SSP5–8.5 this April. The committee declared the scenario implausible and removed it from the framework that will underpin the next IPCC assessment. SSP5–8.5 was the successor to RCP 8.5, which was created in 2011 as a 90th-percentile worst-case stress test.

Modelers built the scenario on assumptions that included 12 billion people on Earth by 2100, technology frozen in place, and a fivefold increase in global coal use. Scientists began warning that the scenario was implausible in 2017. A 2020 paper in Nature stated that it becomes increasingly implausible with every passing year.

Former President Joe Biden’s EPA removed the scenario from regulatory analysis in 2022.

More than 17,000 papers from 2022 through 2025 cited the scenario. The U.S. National Climate Assessment relied on it as recently as 2023. Six states now mandate K–12 climate education built around projections drawn from the scenario. Textbooks presented the most extreme projections as outcomes.

A Lancet study of 10,000 young people found that 59 percent are very or extremely worried about climate change. One in five young Americans aged 16 to 24 reported being afraid to have children, according to a 2025 study.

The committee’s action follows years of continued use despite internal warnings. The Dutch newspaper de Volkskrant covered the decision on its front page. Major outlets including The New York Times, the BBC, Nature, Science, and The Guardian have not reported on the change. The scenario committee stated that SSP5–8.5 is implausible and removed from the framework.