For more than a decade, the Representative Concentration Pathway 8.5 (RCP8.5), the high-emissions climate-model scenario, dominated climate research and policy, treated as the “business-as-usual” pathway. It projected global temperatures to rise by 4.3℃ or more by 2100.
Many climate researchers were on the record noting from the outset that RCP8.5 was “implausible” and shouldn’t be treated as expected or business as usual, yet that didn’t stop many of those same scientists, and the vast majority of others publishing in the peer-reviewed literature and speaking to the mainstream media, from treating it as such, calling for government heads and policymakers to impose a rapid transition away from fossil fuels in order to prevent the disastrous social, economic, and environmental outcomes that RCP8.5 forecast.
Exact counts fluctuate daily, but as of mid-2026, tens of thousands of peer-reviewed climate studies have used RCP8.5. By early 2020 alone, researchers were publishing roughly 20 studies per day using it, with estimates exceeding 8,500 papers in an 18-month period.
I critiqued the use of RCP8.5 for climate science and policy as far back as 2017 in Climate Change Weekly, and I have hammered it repeatedly since then. I have argued, based on scientists’ own statements, that RCP8.5 was not just implausible but impossible. There are many reasons RCP8.5 was a false rallying point for climate policy from its inception, foremost among them perhaps being the fact that not enough recoverable coal exists in the world to produce the assumed fivefold increase in use by 2100. In addition, the human population is not on track, and not under any foreseeable scenario will it be, to increase to the 12.6 billion to 14.5 billion range assumed in the RCP8.5 scenario. In short, my critiques were right: RCP8.5 was a lie from the beginning. All the scientists who used it despite its known weaknesses were wrong.
You don’t have to trust me to know this is true. The U.N. Intergovernmental Panel on Climate Change—which wielded RCP8.5 like a cudgel for years to beat government climate negotiators into multiple unjustified climate treaties—admitted it in mid-April 2026.
In the immortal words of celluloid Die Hard hero John McClane, “Welcome to the party, pal.”
Better late than never, I guess.
Shockingly, RCP8.5 has been used as a reference case in more than 70 peer-reviewed articles despite its official repudiation. The journals publishing these stories can’t even be bothered to withdraw them or post them with a caveat noting the illegitimacy of their findings in light of the key metric for their alarming claims being withdrawn. So much for the vaunted peer-review process.
The IPCC and the lapdog media are treating this conclusion like it’s a new discovery, but it is not. RCP8.5’s implausibility, indeed impossibility, was known to its promoters from the start, but instead of jettisoning it, they built a massive edifice of publications, laws, and regulations based upon its false predictions. In this, they simply followed the advice of an early climate alarmist, the late Dr. Stephen Schneider, who admitted that being honest about the science would undercut efforts to get governments to enact the policy prescriptions alarmists desired. Schneider told Discover magazine,
On the one hand, as scientists we are ethically bound to the scientific method, in effect promising to tell the truth, the whole truth, and nothing but—which means that we must include all doubts, the caveats, the ifs, ands and buts. On the other hand, we are not just scientists but human beings as well. And like most people we’d like to see the world a better place, which in this context translates into our working to reduce the risk of potentially disastrous climate change. To do that we need to get some broad-based support, to capture the public’s imagination. That, of course, means getting loads of media coverage. So we have to offer up scary scenarios, make simplified, dramatic statements, and make little mention of any doubts we might have. … Each of us has to decide what the right balance is between being effective and being honest. I hope that means being both.
Science, as a way of expanding knowledge and discovering truths, is undermined when its practitioners practice Plato’s art of the (ig)noble lie in the pursuit of political ends. That’s just what the IPCC and its fellow travelers have been doing.
“The integrity of science depends on its capacity to provide an ever more reliable picture of how the world works,” wrote Roger Pielke Jr. and Justin Ritchie in their blog post on the public withdrawal of RCP8.5 and the furor that has surrounded its long use and final repudiation. “Over the past decade or so, serious threats to this integrity have come to light,” Pielke and Ritchie write.
“The expectation that science is inherently self-correcting, and that it moves cumulatively and progressively away from false beliefs and toward truth, has been challenged in numerous fields,” the authors write. “A failure of self-correction in science has compromised climate science’s ability to provide plausible views of our collective future,” Pielke and Ritchie accurately state.
I recommend CCW’s readers read their in-depth, informed discussion of the rise and fall of extreme climate scenarios in full.
Now there is an entire website dedicated to bringing to light the whole sordid RCP8.5 scandal. The new website, “they-knew.com,” was established by the Hon. Jason Isaac of the American Energy Institute. Isaac describes the website as follows in the press release announcing it:
They-Knew.com, a comprehensive public record documenting the systematic misuse of RCP8.5, the extreme climate scenario that powered nearly every alarming headline, regulation, court filing, and school curriculum on climate change for over a decade—and that the UN’s own scenario committee officially declared “implausible” in April 2026.
The site chronicles one of the most consequential scientific integrity failures of the century: scientists flagged RCP8.5 as unrealistic as early as 2017, published those warnings in the world’s most prestigious journals, and watched as governments, central banks, courts, educators, and advocacy organizations kept using it anyway.
They-knew.com provides a timeline of the creation, introduction, and misuses of RCP8.5. It documents the organizations and individual power brokers in both the public and private sectors who used RCP8.5 to push flawed, costly, liberty-limiting laws, regulations, and financial policies. The actions by large banks, investment houses, portfolio managers, bureaucrats, and public officials have resulted in private-sector malinvestments that have harmed businesses, retirees, employees, stockholders, and the economy. RCP8.5 also underpinned unjustified government interventions in energy, transportation, infrastructure, and personal appliance markets that have endangered lives and left people poorer and with less choice than they otherwise would have.
All of this has resulted because business and government elites adopted RCP8.5 as the lodestar or guiding force behind corporate and government climate policies. Even if the elites did not actually believe the apocalyptic projections of RCP8.5 were likely or would come to pass, it gave them the “scientific” cover to impose policies they wanted anyway, whether for pecuniary, paternalistic, hubristic, or megalomaniacal reasons.
They-knew.com notes that perhaps the most durable and damaging impact of RCP8.5 is that it was used to indoctrinate and scare a generation of children into the belief that the world was ending because of their and their parents’ energy choices, based on a scenario that scientists privately knew was fiction. They-knew.com details all this and more. Check it out.
I’m sure you will be appropriately disgusted.
This piece originally appeared at Heartland.org and has been republished here with permission.
