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And I can't state this enough: Our estimates of high climate sensitivity are based on the best estimates of available observations. There is a high probability (from a risk perspective) that climate sensitivity is even higher than our seemingly 'higher' (than e.g. IPCC's +3°C for 2xCO₂) estimates.

Climate News@climatenews.bsky.social

Exactly the same logic applies to climate sensitivity. We need to work on the assumption that Dr James Hansen et al is correct with their higher climate sensitivity models because we won’t know if mainstream climate science is completely wrong about low climate sensitivity until it is too late.

Do you have a set of milestones, which will rack up the confidence for the lay person, that ECS is indeed higher? Impacts faster than RCP8.5 expectations? Things do seem to be going fast: GMST, EEI, OHC, SST, MHW, SLR, Ocean (pH, O₂, °C), Sea Ice, Wildfires, 50°C occurrences, high min °C nights.

Hansen right (for 2027), but for the wrong reasons? Roll on another 10 years of data. Hopefully loess trend won't be suggesting we are around 2C be then.

Zeke Hausfather@zekehausfather.com

2027 is now expected to reach 1.7C in my model – exactly where Hansen predicted it would land (albeit in the GISTEMP dataset) back in December 2025: