The Science Has Spoken Against Climate Alarmism

National Review Online

Wednesday, May 20, 2026

 

‘The science” should not be a thing. Science is not dogma, but a voyage of endless intellectual exploration in which blind alleys are part of the process. Some scientific facts may be “settled,” but that’s a difficult determination when we are discussing projections far into the future.

 

And so we come to Representative Concentration Pathway (RCP) 8.5. This was the gloomiest of the four main scenarios prepared for the U.N. Intergovernmental Panel on Climate Change (IPCC) in 2014. Each “pathway” described what was thought would happen if greenhouse gases reached a certain concentration in the atmosphere. If RCP8.5 was followed, the “likely” increase in mean global surface temperature by 2100 would have been 2.6-4.8°C, with a mean of 3.7 °C, a large-scale increase.

 

RCP8.5 — and its roughly analogous but supposedly more sophisticated successor model, known as SSP5-8.5 — was always intended as an extreme scenario, but alarmist advocates and journalists often portrayed it as a baseline. Now, these trajectories have been found to have become “implausible” by the committee responsible for setting out the scenarios for the next IPCC assessment.

 

President Trump reacted to the news with glee: “GOOD RIDDANCE! After 15 years of Dumocrats promising that ‘Climate Change’ is going to destroy the Planet, the United Nations TOP Climate Committee just admitted that its own projections (RCP8.5) were WRONG! WRONG! WRONG!”

 

The truth is more complicated. The authors of the paper in which the scenarios were dismissed as “implausible” attributed the downgrade to “trends in the costs of renewables, the emergence of climate policy and recent emission trends,” an explanation that can be seen as a justification of current climate policy rather than a rejection of it.

 

On the face of it, that’s fair enough. RCP8.5 and SSP5-8.5 have long been described as outliers by more responsible voices in the climate debate, but, wonders AEI’s Roger Pielke, how plausible were they in the first place? In 1994, the IPCC had stated that a scenario must be “a coherent, internally consistent, and plausible description of a possible future state of the world.” That definition has since been repeated on various occasions, but did RCP8.5 or SSP5-8.5 meet its standards? For example, their assumptions included a dramatic, implausible increase in coal’s role as a primary energy source. This appears ludicrous when compared with coal’s weakening share in the early 2010s and, despite coal’s persistence, still does. Similarly, although predictions about the size of the global population have bounced about, the assumption in RCP8.5 that there would be 12 billion of us in 2100 looked very unlikely.

 

In theory, there’s nothing wrong with a forecast — one among many — being found not to measure up. The problem is that for years the forecasts contained within RCP8.5 were described, not as outliers, but as “business as usual,” the planet’s inevitable destination if humanity didn’t adopt a radical course correction. The phrase has long been a staple of alarmist argot, used to portray anything like the energy status quo as a danger and moral abomination. Try as hard as one might, who can forget Greta Thunberg’s “how dare you” at the U.N.? The full sentence read as follows:

 

How dare you say this can be solved with just business as usual and some technical solutions?

 

And Thunberg was only one of a vast horde of activists, rent-seekers, academics, journalists, and politicians who seized on an out-of-date and flawed hypothetical to pursue an extreme climate agenda. If the downgrading of RCP8.5 and SSP5-8.5 changes that, we will be delighted, but we suspect that we will be disappointed. Apocalyptic climate scenarios are too useful to the left to be abandoned easily — whether what they call “the science” supports them or not.