RCP8.5 Update

This is a re-post from And Then There's Physics

If you’ve been paying attention to the climate debate on social media you might have noticed the RCP8.5 debate rearing it’s ugly head again. This is because a new set of emission/concentration projections have been developed for the climate modelling community (CMIP7). These new projections no longer include an RCP8.5-like projection and so all of those who have been critical of its use are now crowing about this proving them right.

I’ve written about RCP8.5 numerous times before. My views have probably evolve somewhat over time, but my previous posts are probably a reasonably good reflection of them. So, if you do want to know them, you could read some of these earlier post. I don’t want to delve too much into the re-invigorated “debate” but instead thought I’d post links to other posts/articles that I think explain the situation pretty well. If you want to read alternative takes, they’re not all that difficult to find. You can probably guess the authors.

I will, though, repeat the sub-heading of Gavin’s Realclimate post:

The fantasy version of the normal updating of scenarios for a new round of CMIP simulations doing the rounds is bad faith BS.

Links to other posts:

Scenarios, Schemarios – Gavin Schmidt at Realclimate.
On the death of RCP8.5 – Zeke Hausfather, Glen Peters and Piers Foster at Climate Brink.
Factcheck: Trump’s false claims about the IPCC and ‘RCP8.5’ climate scenario – multiple authors at Carbon Brief.
IPCC does not create scenarios – Reto Knutti at Linkedin
Sorry, climate change is still dangerous, no matter what nonsense Trump emits – Bulletin article by Genevieve Guenther

Posted by Ken Rice on Monday, 25 May, 2026


Creative Commons License The Skeptical Science website by Skeptical Science is licensed under a Creative Commons Attribution 3.0 Unported License.