The United Nations climate committee has formally scrapped its worst-case warming scenario. The move, finalized earlier this month, retires RCP8.5 and its successor pathways SSP5-8.5 and SSP3-7.0. Those projections assumed a near-tripling of global coal use, no climate policy, and population growth far above any plausible trajectory. For 15 years, they were treated as a baseline. Now they are gone.
President Donald Trump celebrated the decision on Truth Social on Friday. He called it a victory over what he termed “Climate Alarmism nonsense.” He wrote that the projections were “WRONG! WRONG! WRONG!” and accused Democrats of using them to push a “GREEN NEW SCAM.” The president framed the retirement as a win for “TRUTH, SCIENCE, and FACT.”
The real stakes here are not political. They are practical. For more than a decade, governments, central banks, and news outlets used RCP8.5 as a default worst case. It shaped trillions of dollars in investment decisions. It guided insurance risk models. It set the terms for every major climate policy debate. And it was built on assumptions that, by the committee’s own admission, were never plausible.
Consider what RCP8.5 assumed. Coal use nearly triples. No government anywhere enacts meaningful climate policy. Population growth hits the upper bound of demographic projections. That is not a realistic future. It is a stress test. But it was repeatedly presented as “business as usual.” That framing drove headlines, funding, and public fear.
The committee’s decision to retire those scenarios is the most significant shift in climate-scenario practice since the IPCC’s Fifth Assessment Report. The new CMIP7 modeling framework, adopted earlier this month, does not include them. That means the next generation of climate projections will start from a different baseline. One that is, at least, grounded in reality.
What this does not mean is that climate change is not happening. The report does not say that. The committee does not say that. What it says is that one specific set of projections was wrong. Overstated. Implausible. That distinction matters. For years, activists and officials pointed to RCP8.5 as proof of imminent catastrophe. That was a mistake. The data did not support it.
The practical consequence is that policy debates can now be based on actual science, not on a worst-case scenario that was never going to happen. That does not mean the problem is solved. It means the framing has been corrected. And that correction has been a long time coming.
President Trump’s reaction is predictable. He sees the retirement as vindication. He is using it to attack the Green New Deal and climate activism broadly. But the core fact remains: the UN’s own climate committee acknowledged that its signature worst-case projection was implausible. That is a big deal. It changes the terms of the conversation.
For investors, it means risk models need updating. For regulators, it means stress tests based on RCP8.5 are no longer credible. For the public, it means the most alarming climate headlines of the past decade were built on a foundation of sand. That is not a small thing. It is a fundamental shift in how we understand the future.
The committee did not say climate change is a hoax. It did not say warming will stop. It said the worst-case scenario used to scare people was not realistic. That is the truth. And it is a truth that has been a long time coming.
