A twitter thread by Dr. Roger Pielke Jr.

Over coming days, I’ll have a few follow up threads on my @FT piece published online today . . .


🧵The @NGFS_ climate scenarios are interesting in notable respects . . .

In June 2020 @NGFS_ recognized that RCP scenarios underpinning most scenario-based climate studies “do not match well with recent emissions trends”👍

Thus new scenarios were needed, lest they rely on outdated science

So the NGFS created new scenarios…

The new scenarios add even more complexity to the already Byzantine world of climate scenarios … but once you go down the rabbit hole, one can quickly realize that the new scenarios repeat key mistakes of the old scenarios they were to replace…https://data.ene.iiasa.ac.at/ngfs/#/workspaces

The @NGFS_ baseline scenario – called “Hot House World” – is simply implausible projecting ever-increasing emissions to 2100, accelerating late century

Using such an implausible future as a plausible baseline expectation is bound to mislead . . .

Red line is more plausible

A more technical illustration of the same point can be seen below

“Hot House World” is not as extreme as IPCC baselines (SSP-7.0 & SSP-8.5) but it is still far too extreme to serve as a plausible baseline scenario, falling about midway between SSP6.0 & 7.0 outcomes

There is an urgent need to not just update climate scenarios, but to implement a process whereby they can be kept instantaneously current … we can do this, we know how

More here:

More tomorrow … 🔥

Originally tweeted by Roger Pielke Jr. (@RogerPielkeJr) on May 9, 2021.

via Watts Up With That?


May 9, 2021