When scientists quietly update a technical climate modeling framework, it rarely makes headlines. But when President Trump posted on Truth Social declaring that the United Nations’ own climate scientists had admitted their projections were “WRONG! WRONG! WRONG!” the world suddenly needed to understand what RCP8.5 was — and what its retirement actually means. The answer matters. Not because Trump’s version of events is accurate (it isn’t), but because a real development in climate science is being weaponized to tell the public that global warming is no longer a serious problem. That claim is false, and the stakes of getting it wrong are enormous.
The immediate trigger was a peer-reviewed paper by Van Vuuren et al. 2026 laying out new emissions scenarios for the upcoming IPCC Seventh Assessment Report. Trump responded by posting that “the United Nations TOP Climate Committee just admitted that its own projections (RCP8.5) were WRONG.” The post drew immediate criticism from the scientific community — not because the scenario wasn’t being retired, but because the president’s interpretation of why, and what that means, was deeply misleading.
What the Science Actually Says
Contrary to Trump’s claims, the emissions scenarios used by climate scientists are not developed by the IPCC itself. The process is driven by a group of earth system modeling experts convened by the Coupled Model Intercomparison Project, or CMIP. ScenarioMIP released its CMIP7 scenario design in April 2026, eliminating RCP8.5 and related high-end pathways from priority use, citing their divergence from current realities. Previously dominant in research for decades, these scenarios assumed unchecked fossil fuel growth without significant policy intervention.
Why was RCP8.5 retired? Primarily because of what has been done right to reduce emissions since the scenario was first published 15 years ago. Clean energy has become far cheaper, coal expansion has not materialized at the projected scale, and renewable deployment has accelerated dramatically. Those are genuine climate policy successes. But they come with a critical caveat that Trump’s post omits entirely.
The new “high” scenario still projects warming of around 3.3°C by 2100, with a range spanning 2.5°C to 4.4°C. To be clear, that level of warming would still come with catastrophic climate impacts. Van Vuuren himself states the world is “now on a trajectory to 2.5–3°C of warming.” The new scenarios also show it is “not possible” to limit global warming to 1.5°C without significant overshoot, and projections suggest the world remains on course for 2.5°C to 3°C, a level previously described as “catastrophic” by the United Nations.
In other words, the update is not good news dressed up in scientific language — it is a recalibration of how bad things are likely to get, not a reversal of whether they will be bad at all.
The Physics Doesn’t Change With the Politics
There’s a deeper problem with how the RCP8.5 retirement is being framed in conservative media and by the White House. Research has shown that feedbacks in the climate system — where warming triggers the release of more CO2 and methane, which warms the planet further — could mean that human-caused emissions lead to a greater climate impact than initially assumed. This means that even a scenario projecting 3°C of warming from emissions alone could ultimately produce significantly higher actual warming, depending on how carbon feedbacks play out in practice.
Lead author Van Vuuren and Johan Rockström, director of the Potsdam Institute for Climate Impact Research, were explicit: even with the lowest projected warming, “we enter danger,” Rockström said — from extreme events like floods, heat waves, and droughts, as well as from the risk of crossing critical tipping points such as the loss of coral reefs and glaciers.
The National Academy of Sciences issued a report disputing White House climate claims, stating that “human-caused emissions of greenhouse gases and resulting climate change harm the health of people in the United States.” Separately, a group of 85 scientists wrote a letter describing Trump’s characterizations as “misleading or outright wrong.” Meanwhile, Trump’s administration has been rolling back the very policies that made the more optimistic new scenarios plausible. Project 2025, the policy blueprint that shaped much of the Trump administration’s agenda, had already identified the elimination of RCP8.5 from federal use as a “day-one” priority, pushing for the removal of “unrealistic climate scenarios” from EPA regulatory frameworks.
There is a certain irony in a president who has spent his second term dismantling clean energy programs, reopening coal plants, and blocking climate research now citing climate progress as evidence that nothing needs to be done. Climate scientist Zeke Hausfather noted there is still a scenario envisioning what happens if climate progress is rolled back and fossil fuel use expands — describing it as a “very Trumpian future.”
The real conclusion from the updated scenarios is not reassurance — it is urgency with a different label. A world that has made enough progress to retire one worst-case model is not a world that has solved its climate problem. It is a world that has marginally improved its odds while still heading toward temperatures that, as the IPCC’s own assessments have documented, will bring mass displacement, agricultural disruption, and economic instability across multiple continents. Retiring a scenario is not the same as retiring the crisis.
Original analysis inspired by Genevieve Guenther and Michael E. Mann from Bulletin of the Atomic Scientists. Additional research and verification conducted through multiple sources.
