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Moreover values were not used for the full arctic (60-90N).
While I agree that accuracy is important, and appreciate Zeke's work on this, it really is obscene to be carrying on this debate as though we're still serious about the possibility of keeping warming well below 2C given what other recent studies have said, and the early results for ECS from CMIP6.
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wdmn,
I generally do not have time to address most of the assumptions that work their way into various posts in this thread, but I thought that I would clarify my position on some of the matters that you raise.
First, the Arctic Circle is from 66° 33' 39" N. to 90
oN, so the plot you referenced is more relevant than Zeke Hausfather's; and I was merely pointing out that different posts were comparing apples to oranges.
Second, in Zeke Hausfather's following linked article on the SSP scenarios, he notes that SSP2 is most comparable to the relatively new RCP 7.0, and he claims that these scenarios are more likely to be more representative of future anthropogenic forcing than either SSP5 baseline or RCP 8.5. However, before the end of April 2019 global population will be at 7.7 billion people, which is above all of the SSPs estimated global populations in 2019 as shown in the first image from Hausfather's article, and I note that in 2100 RCP 8.5 assumed a world population of about 12 billion while SSP5-baseline assumes a world population of about 7.38 billion people (indicating that SSP5-baseline was rigged to match the radiative forcing of RCP 8.5, significantly by ignoring global population projections). Thus SSP5-baseline seriously underestimates global population, which means to me that even if the people ignored by SSP5-baseline were to only use sustainable energy (see the second attached image for the year 2018) then we would still be following SSP5-baseline and not SSP2.
Title: "Explainer: How ‘Shared Socioeconomic Pathways’ explore future climate change"
https://www.carbonbrief.org/explainer-how-shared-socioeconomic-pathways-explore-future-climate-changeExtract: "While RCP8.5 lives on in the form of the SSP5 baseline, it is now just one of many possible no-new-policy futures. The fact that only one of the SSPs, SSP5, can reach the level of emissions found in RCP8.5 suggests that it may not now be best suited for use as the sole baseline scenario in future research.
If any SSP can be said to be characteristic of current conditions it is SSP2, where social, economic and technological trends do not shift markedly from historical patterns. Greenhouse gas concentrations in the SSP2 baseline roughly correspond to the new RCP7.0, which shows lower emissions and nearly 1C less warming than RCP8.5 – though still 3.8-4.2C of warming above pre-industrial levels."
The second image comes from the IEA report on global energy use thru 2018 at:
https://www.iea.org/geco/Finally, I remind readers that I think that we will only follow SSP5-baseline through circa 2060 when I expect global socio-economic collapse will drop anthropogenic GHG emissions down to something like SSP1.
Best,
ASLR
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