https://richardtol.substack.com/p/new-scenarios
By RICHARD TOL
The latest set of non-IPCC scenarios are out at last. The data are here.
Recall that the governments that ultimately rule the IPCC, find it difficult to sign off on scenarios showing that the promises they made to their electorates may not materialize. Scenario-builders therefore created a consortium that cross-my-heart-and-hope-to-die has nothing to do with the IPCC — they just happen to be much the same crowd.
These are the previous scenarios, SSPs, for carbon dioxide emissions, decomposed according to the Kaya Identity:
And here are the new ones, let’s call them MIPs:
The scenarios for population, per capita income, and energy intensity are much the same. They just ditched SSP4 and SSP5, the two scenarios with really high average income in 2100.
The scenarios for carbon intensity are very different. The much-critized, return-to-coal scenario has been retired. This was just about not-implausible when the SSPs were conceived but already untenable when published. Instead of the two no-renewables SSPs, we now have three MIPs with very rapid decarbonization. Very rapid. Very, very rapid.
…
The large integrated assessment models keep growing by adding more detail on energy technologies, which now includes agriculture. Unfortunately, they do not add to the economics and politics. Indeed, the difference between SSPs and MIPs is energy supply — as if we didn’t have 15 years of additional data and insights into demographics, economic growth, and energy demand. As Chris Bateille noted, I’m “not sure whether to comment seriously or laugh hysterically”.
