A Truth Social Post Meets the Literature
On May 16, 2026, Donald Trump posted on social media: “The United Nations TOP Climate Committee just admitted that its own climate projections (RCP8.5) were WRONG! WRONG! WRONG!” As CBC News reported the following week, the claim collided with the actual record in almost every particular. The projection in question was retired not by a UN committee, but by scientists in an April review paper. And the reason was not failure but partial success: emissions have come down enough that the worst-case pathway now looks implausible.
The scenario itself, RCP 8.5, was one of four Representative Concentration Pathways published in 2011, sketching futures that ranged from aggressive mitigation to unrestricted coal and fossil fuel burning through the rest of the century. If the extreme branch had played out, global average temperature was estimated to climb as much as 4.3 C over pre-industrial levels by 2100. Skepticism about it predates Trump by years; University of British Columbia researchers Justin Ritchie and Hadi Dowlatabadi argued back in 2017 that the pathway “dramatically overestimated future coal use.”
Why the Worst Case Faded
Zeke Hausfather, a climate scientist at Berkeley Earth and a lead author on the upcoming IPCC Seventh Assessment Report, walked CBC through the mechanics. “When this scenario was created, the world had just seen a huge increase in CO2 concentrations,” he said, noting the RCPs followed a decade in which global emissions rose 30 per cent. The pathway, he added, was often misrepresented as the default future rather than an extreme one. The April paper judged it implausible because climate policy emerged, renewables kept getting cheaper and more widely adopted, and emissions trends shifted; the same paper proposed a new scenario set. “I think there is a welcome re-centreing of what is actually likely to happen based on how the world has changed,” Hausfather said.
Rick Smith, president of the Canadian Climate Institute, called the retirement “truly a good news, bad news story”. The ceiling is lower than feared, he said: “The worst-case scenario of how terrible things might get in terms of warming by the end of the century is not quite as bad as we thought”. The floor, though, has risen too. Wind and solar development, which has now surpassed coal generation globally, slowed heating but did not stop it, and he put the world on a trajectory toward an average rise of 2.5 to 3 C in the coming decades, against the 1.5 C the Paris Agreement targeted in 2015.
The Scenario That Survives
One new pathway still imagines progress rolled back and fossil fuels ramped up, what Hausfather described as a “very Trumpian future.” He argued for keeping it in the set because, as current US politics shows, such turns can happen. His verdict on the whole affair was quiet: “This is just an example of how science works”. Canada, for its part, has warmed roughly double the global average, about 2.5 degrees since 1950, which is why Smith called the remaining trajectory a big concern rather than a victory lap.
