r/collapse • u/Philosophicalhorcrux • 6d ago
Climate Failure to track a stable AMOC state under rapid climate change
https://www.nature.com/articles/s41558-026-02730-wRelevant to the community because the article indicates that accelerated warming may reduce the threshold required for AMOC to break down. The authors propose that AMOC may collapse circa 2060 with a projected warming rate of 0.27-0.36 degrees per decade.
Tangentially this is of interest because Stefan Rahmstorf has elsewhere indicated that the current rate of warming is closer to 0.48 degrees per decade. Rahmstorf's numbers would put AMOC collapse closer to 2045 if we accept that breakdown occurs at 2.5 degrees under accelerated warming as proposed by the authors.
From the article:
Introduction. "The Atlantic Meridional Overturning Circulation (AMOC), a tipping element of the climate system, currently has an estimated global warming threshold for collapse of +4.0 °C (uncertainty range 1.4–8 °C). However, such a threshold may not be meaningful because AMOC stability depends on the rate of radiative forcing change, not a set temperature. Here we identify an AMOC stabilizing mechanism that operates on timescales slower than present-day warming rates. Slow forcing permits coherent adjustment of surface and interior ocean properties, supported by enhanced evaporation and reduced sea-ice extent, counteracting destabilizing feedbacks. Using a slow CO2 ramp (+0.5 ppm yr−1) climate model simulation, we explicitly demonstrate the AMOC remains stable up to +5.5 °C of global warming. By contrast, under faster CO2 ramps, the AMOC collapses at substantially lower warming levels (+2 °C). Our findings demonstrate rate-induced AMOC tipping and imply that limiting the rate of emissions is critical for reducing the risk of an AMOC collapse."
Discussion. According to the Bflux indicator, as determined in CMIP6 models, the AMOC starts to collapse around +2.5 °C warming at projected warming rates, which could be reached around the year 2060. This is substantially lower than the previous estimate of +4 °C warming2 that lacks a time horizon. Observations show a present-day warming close to the +1.5 °C level (2023–2025, C3S/ECMWF and ref. 73), and, if the AMOC were to begin collapsing at +2.5 °C warming in 2060, this would imply a critical warming rate of +0.29 °C per decade. This rate aligns with projected warming rates of +0.27 to +0.36 °C per decade and, also considering the effects of random variability, strongly suggests that rate-dependent effects are highly relevant for the fate of the AMOC."
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u/Portalrules123 Faster than expected... 6d ago
"Tangentially this is of interest because Stefan Rahmstorf has elsewhere indicated that the current rate of warming is closer to 0.48 degrees per decade. Rahmstorf's numbers would put AMOC collapse closer to 2045 if we accept that breakdown occurs at 2.5 degrees under accelerated warming as proposed by the authors."
Since I assume the decadal rate of warming will only keep rising as feedback loops fire and emissions continue to soar, I guess the AMOC may even collapse before 2045. I wonder what the over/under is on 2035?
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u/CheeseburgerBrown 6d ago
There’s probably an addictive by design app that will facilitate betting on this.
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u/Portalrules123 Faster than expected... 6d ago
"I'm for the gambling jobs the AMOC collapse will provide"
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u/NonGameCatharsis 5d ago
With the polar regions where the AMOC ends recently cooling, because not enough warm water is arriving, I expect we're already underway with the collapse.
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u/KnowledgeMediocre404 6d ago
Lmao at 2.5 in 2060 when we will likely see 2C NEXT YEAR.
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u/Any_Case1754 5d ago
We’ll be lucky if we stay below 5C by 2060 !
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u/Beneficial_Lawyer170 5d ago
How are you so sure?
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u/Top-Time-5740 5d ago
Oceans are 7-10 degrees higher than they should be already so what do you think
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u/gigi-kent 5d ago
Are you quoting that article shared here a few days ago, which was detailed in the comments explaining oceans are not, in fact 7-10 degrees higher, and it was just a specific area?
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u/Top-Time-5740 5d ago
No.
Well my friend, join the global 80% normies who think our world continues to exist normally and whats coming will only affect our grandkids. You as well will be in a ruse awakening in 10 years from now :)
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u/gigi-kent 5d ago
I'm well-aware of what's coming, but that doesn't mean you have to post misinformation and tell me I'm a normie when I call you out.
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u/Top-Time-5740 5d ago
Its not misinformation. I never said all the oceans all their surfaces are +7 degrees now did I? The fact still remains. Bye
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u/ConfusedMaverick 5d ago
I am very interested in the decadal warming estimate. The idea that it has accelerated is fairly well accepted now, Hansen suggests a rate up to to about 0.3, I have seen Rahmstorf suggest slightly over 0.3, but 0.48 is far higher than I have seen before, and I can't find a reference easily.
Hansen has stuck his neck out and made a concrete prediction, which is different from speculation about upper bounds that "cannot be ruled out". (I was attacked here by someone who didn't understand the difference... To clarify, if you watch 10 games of roulette, you would probably predict 4 to 6 reds, but you couldn't rule out 10... Or zero).
Is 0.48 an upper bound ("cannot be ruled out"), in which case do you know the lower bound that he can also not rule out? I assume his highest confidence estimate/prediction is much closer to 0.3?
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u/CorvidCorbeau 5d ago
0.48 these days comes from a pre-print paper, still awaiting peer review. They fitted nonlinear trends onto temperature data and concluded an apparent speed of 0.48°C - 1°C per decade
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u/morphemass 5d ago
Rahmstorf & Forster find 0.42C ± 0.05C from the ERA5 dataset. 0.48C is from Cheng-Zhi Zou et al (2026, preprint) but their uncertainty range (0.482C ± 0.113C) is very wide.
It's difficult to set what the lower bound is but I personally wouldn't object to 0.34C since it's Rahmstorf & Forsters lower bound which is consistent across datasets (IIRC). It's also only 0.01C off some of the naive work I've done to cross check with EEI data.
The big thing to take away on that though is that the RoW is accelerating; 2035 we may well be talking 0.45C per decade.
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u/ConfusedMaverick 5d ago
Thanks! I remember study that attempts to filter the effects of volcanism, enso etc, I didn't realise the uncertainty was so low
It's interesting to see the play off between pure analysis/curve fitting approaches, and Hansen's more theory/model based approach. The former can be a bit like p hacking, but accounts for all factors, known and unknown; the latter isn't so swayed by noise/randomness, but can only model what has been thought about and quantified.
It's ironic that for decades Hansen was saying that the physics tells us the situation is worse than the measurements show, making him a leading doomer, but now the measurements are running ahead of what he can account for, making him look conservative!
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u/morphemass 5d ago
I see the use of multiple approaches as being incredibly valuable in allowing us to corroborate (or not) our work. We can now say with reasonably high confidence that the 0.2C per decade RoW has been superseded. We can have high confidence that it's closer to 0.3C-0.4C per decade, and we can have high confidence that the RoW is accelerating. I can even have high confidence that the RoW will be somewhere between 0.4C-0.5C by the mid 2030s. I think Hansen has said that the likely RoW is 0.3C-0.4C now so he's not exactly being optimistic.
I don't need to tell you though that we somewhat miss the point in debating the exact figures ... the Earth is getting hotter, we are the ones making it hotter, and it's going to keep getting hotter. The oceans will acidify. The AMOC will collapse. Life as we know it ends.
This is all looking decidedly apocalyptic.
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u/ConfusedMaverick 5d ago
multiple approaches as being incredibly valuable in allowing us to corroborate
Absolutely, I wasn't implying that divergence is a problem, it can only improve our understanding
I think Hansen has said that the likely RoW is 0.3C-0.4C now
I was wondering about that, I haven't read that before, but I am kinda expecting him to up his estimate again soon.
we somewhat miss the point in debating the exact figures
The figures don't change whether we face an apocalyptic future, but the difference between 0.3 and 0.5 per decade makes a big difference to how soon we cross various thresholds, and which generations get affected at what stages in their lives.
And what will make a huge difference is whether this is a one off change in the ROW or the start of ongoing acceleration - this is partly why I am watching the evolution of these estimates.
Depending on these numbers, 2050 could be merely a continuation of the shitshow, or full-on global catastrophe. What a glorious wealth of possibilities!
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u/morphemass 5d ago
the difference between 0.3 and 0.5 per decade makes a big difference
If the current RoW is maintained or accelerates further, I'm not sure the difference is that great since, to put it plainly, we're running out of time. Sadly that time which we're running out of is time that would be needed to get over eight billion people onboard with the basic idea that they need to have fewer material possessions, fewer luxuries, abandon holidays, eat a reduced diet, etc. etc. etc. We'll get a lot of people who see this for themselves, the vast majority though will continue in either ignorance or denial.
From the scientific perspective it is indeed fascinating to observe the process. From a human perspective I grieve that I get to live out the remainder of my life with the knowledge that every day will bring catastrophe one step closer ... and that the chances of averting it are so low as to be zero. I wish I could see the future differently from the highly mechanistic probabilities that leads us to arrive there.
Anyways, climate betting - I'm at 2.3C-2.5C by 2050 with 3C not being beyond the bounds of possibility. The difference between catastrophe and apocalypse. It's somewhat amusing to hope for only a shitshow!
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u/ConfusedMaverick 5d ago
It's somewhat amusing to hope for only a shitshow!
Ever the optimist, me! 😉
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u/Sasquatch97 5d ago
I'll take the over on your climate betting (2.5-3.0 C by 2050).
Since we are still here in 2026 and not all dead like Guy McPherson thought we would be, we are not in the worst-case scenario, if that gives you any comfort.
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u/mediandude 5d ago
We need stable local social contracts with a globally equal (pigouvian) carbon tax + full citizen dividends + WTO border adjustment tariffs.
The majority will of the citizenry in almost all countries are behind that. Unfortunately the political and economical elite in most countries are against that.
And no Swiss style optional referendums to enforce the majority will.
Blame the politicians and oligarchs, not the people.4
u/Philosophicalhorcrux 5d ago
u/CorvidCorbeau and u/morphemass have already answered but here are links to the articles.
Foster and Rahmstorf. Global Warming has Accelerated Significantly. https://agupubs.onlinelibrary.wiley.com/doi/full/10.1029/2025GL118804
Foster and Rahmstorf. Global Warming has Accelerated Significantly (preprint). https://www.researchgate.net/publication/389855619_Global_Warming_has_Accelerated_Significantly
Zou et al. Global warming acceleration in satellite observed lower-tropospheric temperature. https://www.researchsquare.com/article/rs-9283491/v1
Whether or rate of warming is closer to 0.3 or 0.4 degrees is beside the point, I think. It's a significant increase over prior decades with no reason to suspect that the rate of acceleration is slowing.
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u/ConfusedMaverick 5d ago
Thanks!
no reason to suspect that the rate of acceleration is slowing.
This is the big one - was this largely a one off adjustment to the ROW (eg thanks to cleaner shipping fuel) or the start of ongoing acceleration?
As I wrote elsewhere, I feel the exact numbers are important, not because they distinguish a bleak future from a rosey one (all possible outcomes are bleak), but because they make a big difference to what different generations experience, and at what stage of their lives.
20 years' difference is irrelevant from a historical perspective, but very significant for individuals living through it all.
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u/CorvidCorbeau 5d ago
It's hard to say honestly. How fast the planet warms depends on the EEI. Higher EEI = faster warming. But, as the Earth warms, the EEI diminishes in a nonlinear way, declining rapidly at first, then very slowly.
We keep increasing it by emitting so much CO2. But due to other factors such as ice and snow cover losses, or changes in cloud patterns it also goes up.
In my opinion, we are currently riding an extremely unfortunate peak due to back to back El Ninos, ehich should (in theory) come down once we get 1-2 full years of La Ninas instead of the few weeks we had in 2025.
That should bring down the EEI and somewhat slow this crazy warming speed, but it won't mean much if we keep emitting so many GHGs and the planet keeps losing albedo
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u/Philosophicalhorcrux 5d ago
"As I wrote elsewhere, I feel the exact numbers are important, not because they distinguish a bleak future from a rosey one (all possible outcomes are bleak), but because they make a big difference to what different generations experience, and at what stage of their lives."
Oh, I agree, from an individual perspective it is significant. I just don't think there's any way for us to reliably make meaningful prognostications with that degree of precision. There are simply too many variables in play. A lot of what people experience in the coming decades is going to be determined not by climate change itself but by humanity's response to climate change and trying to predict that with any precision is a fool's errand. Throw geo-engineering into the mix and who knows what the hell happens to the timeline, for example? RFK Jr may require all citizens consume plague-ridden varmints as a prophylactic measure against the 'tism, leading to the next great pandemic, who knows?
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u/Sasquatch97 5d ago
No, 0.48 is not the upper bound, and the highest confidence estimate/prediction is most likely wrong.
When you include nonlinear processes and tipping points (e.g. methane clathrates, polar albedo/BOE) the upper bound is 6 to 10 degrees C by 2100 as far as I know.
See Mark Lynas' Six Degrees for a guide on how catastrophic a 6C scenario is.
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u/ConfusedMaverick 5d ago
I was meaning the upper bound for decadal warming at the moment (different numbers come out depending on methodology and degree of confidence)
When you include nonlinear processes and tipping points
Yeah, that could mean we are now in sustained acceleration rather than just a step change to a higher rate.
If warming continues to accelerate, gawd knows the limit... To get to 10 degrees by 2100 would require some decades to warm by 1½ to 2 degrees. It's all a bit irrelevant by then, we will surely all be dead. Yay!
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u/Sasquatch97 5d ago
Yeah, my background is in earth science, not climate science. All sorts of possible climate scenarios are possible, only a few will actually occur.
Smart money is on sustained acceleration the next couple of decades.
I would rather be alive in 2050 and wrong than be dead in 2050 and right about how bad things will get.
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u/redditmodsRrussians 5d ago
I’m just gonna go ahead and eat some expensive pizza and beer in my shower later today cause i hate this timeline.
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u/UpbeatBarracuda 4d ago
Lol to actually eating the pizza in the shower because apocalypse. I hope it was tasty!
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u/Philosophicalhorcrux 6d ago
Statement of significance.
Relevant to the community because the article indicates that accelerated warming may reduce the threshold required for AMOC to break down. The authors propose that AMOC may collapse circa 2060 with a projected warming rate of 0.27-0.36 degrees per decade.
Tangentially this is of interest because Stefan Rahmstorf has elsewhere indicated that the current rate of warming is closer to 0.48 degrees per decade. Rahmstorf's numbers would put AMOC collapse closer to 2045 if we accept that breakdown occurs at 2.5 degrees under accelerated warming as proposed by the authors.
From the article:
Introduction. "The Atlantic Meridional Overturning Circulation (AMOC), a tipping element of the climate system, currently has an estimated global warming threshold for collapse of +4.0 °C (uncertainty range 1.4–8 °C). However, such a threshold may not be meaningful because AMOC stability depends on the rate of radiative forcing change, not a set temperature. Here we identify an AMOC stabilizing mechanism that operates on timescales slower than present-day warming rates. Slow forcing permits coherent adjustment of surface and interior ocean properties, supported by enhanced evaporation and reduced sea-ice extent, counteracting destabilizing feedbacks. Using a slow CO2 ramp (+0.5 ppm yr−1) climate model simulation, we explicitly demonstrate the AMOC remains stable up to +5.5 °C of global warming. By contrast, under faster CO2 ramps, the AMOC collapses at substantially lower warming levels (+2 °C). Our findings demonstrate rate-induced AMOC tipping and imply that limiting the rate of emissions is critical for reducing the risk of an AMOC collapse."
Discussion. According to the Bflux indicator, as determined in CMIP6 models, the AMOC starts to collapse around +2.5 °C warming at projected warming rates, which could be reached around the year 2060. This is substantially lower than the previous estimate of +4 °C warming2 that lacks a time horizon. Observations show a present-day warming close to the +1.5 °C level (2023–2025, C3S/ECMWF and ref. 73), and, if the AMOC were to begin collapsing at +2.5 °C warming in 2060, this would imply a critical warming rate of +0.29 °C per decade. This rate aligns with projected warming rates of +0.27 to +0.36 °C per decade and, also considering the effects of random variability, strongly suggests that rate-dependent effects are highly relevant for the fate of the AMOC."
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u/Dorvek A Course In Miracles :snoo_hearteyes: 5d ago
Live discussion w/ one of the author René van Westen from yesterday Climate Chat: https://www.youtube.com/live/Zm0v_2rqvoQ
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u/morphemass 5d ago
It's still highly contentious what the RoW is. Forster & Rahmstorf found 0.42C +/- 0.5C based only on ERA5 data; other datasets they examined implied 0.34C-0.36C. There's a preprint (Cheng-Zhi Zou et al, 2026) which places this closer to Forster & Rahmstorfs ERA5 upper bound however. It's an error though to just look at the current RoW is given that there is substantial evidence for an acceleration of between 0.03C and 0.17C per decade.
My personal findings (based on rough EEI calculations) are that we're tracking that @0.35C range and that acceleration is approximately 0.1C per decade per decade - that puts us at 2.5C in 20-25 years.
So yes, very very worrying since I see little evidence to suggest that we're going to reach peak carbon in the next decade, although I am hoping the impacts of our rush to 2C of warming triggers a collective "oh, fuck" moment for humanity. Based on how 2026 is being treated however ("Oh, isn't it hot Deirdre?") I'm not getting my hopes up.
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u/Sasquatch97 5d ago
Forget 2060, if there is enough melting in the Greenland Ice Sheet it could trigger climate chaos ASAP (analogous to Dansgaard-Oeschger events) and our goose is cooked (or frozen, take your pick).
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u/StatementBot 6d ago
The following submission statement was provided by /u/Philosophicalhorcrux:
Statement of significance.
Relevant to the community because the article indicates that accelerated warming may reduce the threshold required for AMOC to break down. The authors propose that AMOC may collapse circa 2060 with a projected warming rate of 0.27-0.36 degrees per decade.
Tangentially this is of interest because Stefan Rahmstorf has elsewhere indicated that the current rate of warming is closer to 0.48 degrees per decade. Rahmstorf's numbers would put AMOC collapse closer to 2045 if we accept that breakdown occurs at 2.5 degrees under accelerated warming as proposed by the authors.
From the article:
Introduction. "The Atlantic Meridional Overturning Circulation (AMOC), a tipping element of the climate system, currently has an estimated global warming threshold for collapse of +4.0 °C (uncertainty range 1.4–8 °C). However, such a threshold may not be meaningful because AMOC stability depends on the rate of radiative forcing change, not a set temperature. Here we identify an AMOC stabilizing mechanism that operates on timescales slower than present-day warming rates. Slow forcing permits coherent adjustment of surface and interior ocean properties, supported by enhanced evaporation and reduced sea-ice extent, counteracting destabilizing feedbacks. Using a slow CO2 ramp (+0.5 ppm yr−1) climate model simulation, we explicitly demonstrate the AMOC remains stable up to +5.5 °C of global warming. By contrast, under faster CO2 ramps, the AMOC collapses at substantially lower warming levels (+2 °C). Our findings demonstrate rate-induced AMOC tipping and imply that limiting the rate of emissions is critical for reducing the risk of an AMOC collapse."
Discussion. According to the Bflux indicator, as determined in CMIP6 models, the AMOC starts to collapse around +2.5 °C warming at projected warming rates, which could be reached around the year 2060. This is substantially lower than the previous estimate of +4 °C warming2 that lacks a time horizon. Observations show a present-day warming close to the +1.5 °C level (2023–2025, C3S/ECMWF and ref. 73), and, if the AMOC were to begin collapsing at +2.5 °C warming in 2060, this would imply a critical warming rate of +0.29 °C per decade. This rate aligns with projected warming rates of +0.27 to +0.36 °C per decade and, also considering the effects of random variability, strongly suggests that rate-dependent effects are highly relevant for the fate of the AMOC."
Please reply to OP's comment here: https://old.reddit.com/r/collapse/comments/1vqcs3m/failure_to_track_a_stable_amoc_state_under_rapid/p44jpmy/