I really like Hansen's approach & delivery of his reasoning; and if I've learned anything about climate, it's that his projections prove quite prescient. I certainly wouldn't bet against anything he forecasts.
Really appreciate your work, this update, and the clarification/distinction between your underlying philosophies. 👍🏻
A connected question is why the El Nlno is so strong, and whether that is connected to a stronger aerosol effect than the IPCC's mean value. We may have to wait for the next El Nino to get a good answer.
... Of course the fact that Hansen might be right (or put otherwise, that the actual aerosol effect may be near the upper end of what the IPCC finds possible) is reason enough for urgent action, just in case.
I'm not a dynamicist but it seems unlikely for there to be a strong link between aerosols (at least the IMO shipping rules) and El Nino, given that their forcing impact is fairly localized and there are few shipping tracks in the ENSO regions. But I'm not too familiar with the literature here!
In the end, for me , it's record-schmecord. It's somehow entertaining, yes, but the bottom line is: the whole thing is becoming somewhat uncomfortably fast.
Slightly OT: cloud simulation has been the achilles heel of earth models until now - the biggest source of uncertainty. The discussion around lower albedo, faster warming is largely centered around clouds. Better modelling would be invaluable here. So, as a suggestion, I would really love to see a post about AR7 models and progress in cloud simulation.
In footnote 4, when you say, “I’d personally give a central estimate closer to 3.5C than Hansen’s ~4.5C, as well as a new preprint suggesting forcing from the 2020 IMO low sulfur shipping fuel regulations may end up somewhere between Hansen’s high and my low-end estimate,” are you implying that this new pre-print actually provides evidence that ECS is more modest than Hansen would guess?
I am partially curious because your estimate seems to have gone up—from 3C to 3.5C.
I've not followed Hansen or his team for long, but this isn't the first time he's made a less-than-pleasant remark towards Hausfather's way. Is this kind of behavior something he's known for?
That's good to hear. I thought your post was very gracious towards Hansen. I appreciate both methods, and there is definitely value in them both. The statistical method provides particular value when it varies from the observed values, and it is always good to look for the underlying physics. Anyway, thanks for all the work you put into this - much appreciated.
I’ve seen some discussion of this El Niño possibly causing a land temp of 3C. With how strong this El Niño is being forecasted to be, do you think that’s a possibility? (Also the fading old nag line feels kinda mean.)
Big fan of both of you.
I really like Hansen's approach & delivery of his reasoning; and if I've learned anything about climate, it's that his projections prove quite prescient. I certainly wouldn't bet against anything he forecasts.
Really appreciate your work, this update, and the clarification/distinction between your underlying philosophies. 👍🏻
A connected question is why the El Nlno is so strong, and whether that is connected to a stronger aerosol effect than the IPCC's mean value. We may have to wait for the next El Nino to get a good answer.
... Of course the fact that Hansen might be right (or put otherwise, that the actual aerosol effect may be near the upper end of what the IPCC finds possible) is reason enough for urgent action, just in case.
I'm not a dynamicist but it seems unlikely for there to be a strong link between aerosols (at least the IMO shipping rules) and El Nino, given that their forcing impact is fairly localized and there are few shipping tracks in the ENSO regions. But I'm not too familiar with the literature here!
In the end, for me , it's record-schmecord. It's somehow entertaining, yes, but the bottom line is: the whole thing is becoming somewhat uncomfortably fast.
Slightly OT: cloud simulation has been the achilles heel of earth models until now - the biggest source of uncertainty. The discussion around lower albedo, faster warming is largely centered around clouds. Better modelling would be invaluable here. So, as a suggestion, I would really love to see a post about AR7 models and progress in cloud simulation.
These little tussles amuse us at the end of times.
Congrats with this excellent analysis
Informative as always.
In footnote 4, when you say, “I’d personally give a central estimate closer to 3.5C than Hansen’s ~4.5C, as well as a new preprint suggesting forcing from the 2020 IMO low sulfur shipping fuel regulations may end up somewhere between Hansen’s high and my low-end estimate,” are you implying that this new pre-print actually provides evidence that ECS is more modest than Hansen would guess?
I am partially curious because your estimate seems to have gone up—from 3C to 3.5C.
Directionally, that is not reassuring.
I've not followed Hansen or his team for long, but this isn't the first time he's made a less-than-pleasant remark towards Hausfather's way. Is this kind of behavior something he's known for?
Jim and I get along well behind the scenes. I just read it as some good old fashioned shit talking 😉
I'm glad to hear that's the case, because when taken as some professional banter this is genuinely entertaining to read! :)
I love the idea of a dead heat between you and Jim. But, I'll be dead from that heat 🥵
That's good to hear. I thought your post was very gracious towards Hansen. I appreciate both methods, and there is definitely value in them both. The statistical method provides particular value when it varies from the observed values, and it is always good to look for the underlying physics. Anyway, thanks for all the work you put into this - much appreciated.
I like the idea of you and Jim together finish '26 in a dead heat. But, I'll be dead from the heat 🥵
Thank you, Zeke.
I’ve seen some discussion of this El Niño possibly causing a land temp of 3C. With how strong this El Niño is being forecasted to be, do you think that’s a possibility? (Also the fading old nag line feels kinda mean.)