I’ve been getting a lot of media queries about a new paper on the AMOC (Atlantic Meridional Overturning Circulation), which has just been published. In my view this large media interest is perhaps due to confusing messages conveyed in the title of the paper and in press releases about it by the journal Nature and by the Met Office. Whether intended or not, these give the impression that new model results suggest that the AMOC is more resilient than previously thought. That’s (unfortunately!) not the case.
This new paper does not (and does not claim to) contradict earlier modeling studies about future AMOC changes and their climatic impact, as one of the authors (Richard Wood) has confirmed to me (we are presently both attending an AMOC workshop in Utrecht). It’s the same models, showing the same things – just the wording is different. What previous studies have labelled an ‘AMOC collapse’ is now called ‘no collapse’. It’s essentially a discussion about semantics, not physics. Do you call it an AMOC collapse if a weak and shallow wind-driven overturning persists after the thermohaline part has collapsed? Or not?
That is not about any difference in climate impact. The AMOC’s climate impact in these model simulations is the same as in previous studies, which have indeed used the same models and often in fact the same model experiments, as this study has analysed existing model runs.
A typical example of those is the paper by Bellomo et al. 2023 using the EC-Earth3 model – that same model is also included in the new paper by Baker et al. If you try to kill the AMOC by adding a lot of freshwater to the northern Atlantic (no greenhouse gas increase), you get the following change on Atlantic overturning (Fig. 1).
It is clear that – as usual – some overturning remains. The climate impact looks similar to other models (Figure 2): massive cooling in the Northern Hemisphere.
Figure 2 Surface temperature change in response to a near-shutdown of the AMOC.
Another example is the analysis of CMIP6 results which I showed in my presentation last October at the Arctic Circle Assembly, when presenting the open letter by 44 experts to the Council of Nordic Ministers. The preprint of this work has been online since last September. CMIP6 is the current model generation, also used in Baker et al.
It presents a selection of standard climate scenarios with those CMIP6 models, as shown in the last IPCC report, in which the AMOC largely grinds to a halt in the next century, as shown in Figure 3.
Figure 3 AMOC strength and ocean heat transport at 26°N in a selection of CMIP6 models in which the AMOC nearly collapses.
It is clear that some overturning remains in all of them – as is indeed expected, as it is the density-driven (i.e. thermohaline) part of the AMOC which has a well-known tipping point, due to Stommel’s (1961) famous salt transport feedback. It has been well-established since the 1990s (Toggweiler and Samuels 1995) that the AMOC also has a component driven by the winds, which will persist as long as the winds won’t stop blowing (except possibly if it switches to the North Pacific rather than North Atlantic). We actually pointed out in our preprint mentioned above that we focus on whether “the deeper thermohaline part of the AMOC becomes weak and/or collapses, since it is only this part of the AMOC that possesses a tipping point.” Now the new paper focuses on the wind-driven part, which thus complements our study, but it does in no way contradict it.
It does not change the assessment of the risk and impact of future AMOC changes in response to human-caused global warming.
(Please post a link in the comments if you see media coverage of the Baker study.)
Post script: As an aside, together with my Australian colleague Matt England I published a systematic study on the wind-driven part of the AMOC already in 1997.
https://social.heise.de/@heiseonline/114071080822555955
Thanks for providing this insight.
A question that has often occurred to me, to be forgotten before I have a chance to research (or even ask), is
How does an AMOC shutdown affect the planet’s energy imbalance?
Cooler Northern Hemisphere means reduced energy transfer there. I don’t see any compensation for that, so my preliminary guess is that it accelerates overall warming?
Thanks
BJ
This article was written by AI, if you study AI, the way it writes, you’ll see that this is an example of how news can be fabricated to the public.
If I were writing this article or ANY article using acronym, at the first use of the acronym I would make a point of defining what it stood for.
Many may know but many may not, requiring them to google or click on a link to know what
AMOC stands for in this case.
Good point, done.
https://www.zeit.de/wissen/umwelt/2025-02/amoc-stroemung-kanada-temperaturen-europa
https://www.theguardian.com/environment/2025/feb/26/total-collapse-of-vital-atlantic-currents-unlikely-this-century-study-finds
https://www.spiegel.de/wissenschaft/natur/klimawandel-studie-widerspricht-kollaps-des-golfstroms-im-21-jahrhundert-a-51a181db-733b-4bfa-940a-65203a9111ad
Unfortunately, the prediction of a misinterpretation of the findings of the mentioned study by the media seems to hold.
It was obvious that it would, given the irresponsible way in which the paper’s headline and abstract were worded.
I’m in two minds whether the authord and publisher were intentionally irresponsible (in order to get more publicity for the paper), or unintentionally so (in the sense that they genuinely had no idea how laymen would interpret it). The latter is no better than the former, in my opinion. It wouldn’t cost much to employ layman proof readers.
Also in Poland – even in left-of-the-centre Gazeta Wyborcza, with the obligatory denier’s pun:
26/02/2025 “Let’s not let ourselves run amok. New study on the future of the Gulf Stream”
Global warming does not mean that Europe is cooling, scientists write in Nature. […]
You probably remember the headlines from recent years: “The Gulf Stream is weakening”, “A threat to the Earth”, “The Gulf Stream may disappear”.
Where does this hysteria come from?”
=================
The people who wrote the paper seem to have no idea about communication – what they wrote in the headine and the abstract could hardly be more misleading to a layman – and in the current politcal climate (!) I think that is irresponsible.
Surely it should be possible for authors of papers like this – and for the publishers – to get the wording of headlines and abstracts checked by someone who understands how laymen are likely to interpret what they write, before publication?
Herr we go:
https://www.spiegel.de/wissenschaft/natur/klimawandel-studie-widerspricht-kollaps-des-golfstroms-im-21-jahrhundert-a-51a181db-733b-4bfa-940a-65203a9111ad?sara_ref=re-xx-cp-sh
I’m no scientist so maybe explain this in common language? Thanks.
[Response: New scientific study says that what nobody has ever predicted (namely that a particular ocean current vanishes completely, to zero, nothing) is not going to happen, just like all previous model simulations have already shown. The lead author says this is “reassuring”. Lay people might misunderstand this as saying that the severe climate impacts resulting from a major weakening of that current are not going to happen – but these severe impacts have been demonstrated in models where this current also didn’t reduce to zero, and the new study says nothing about climate impacts. So there is nothing new and reassuring about these climate impacts. -Stefan]
https://www.theguardian.com/environment/2025/feb/26/total-collapse-of-vital-atlantic-currents-unlikely-this-century-study-finds
https://apnews.com/article/climate-abrupt-shutdown-atlantic-current-amoc-113045605001da12127166e1b562f4c0
https://www.irishtimes.com/environment/climate-crisis/2025/02/26/amoc-will-weaken-but-may-not-collapse-this-century-study-finds/
https://www.metoffice.gov.uk/about-us/news-and-media/media-centre/weather-and-climate-news/2025/climate-change-amoc-likely-to-withstand-future-warming
I am very interested in learning more about the connection, interaction, the modification of the southern deep ocean and AMOC slow-down. Please elaborate more on this combined construct, so far this appears to be only being assessed independently from each other, and how it potentially will affect Europe and the U.S. East coast.
https://nos.nl/collectie/13871/artikel/2557408-oceaanstroming-die-europa-verwarmt-kan-fors-verzwakken-maar-stopt-waarschijnlijk-niet
https://www.knmi.nl/over-het-knmi/nieuws/in-hoeverre-zal-de-golfstroom-verzwakken-onder-klimaatverandering-amoc-tipping-point
Dutch paper: https://www.nrc.nl/nieuws/2025/02/26/belangrijkste-stroming-in-atlantische-oceaan-zal-deze-eeuw-nog-niet-stilvallen-a4884512
https://www.aoml.noaa.gov/atlantic-meridional-overturning-circulation-weakening-in-the-deep-sea-of-north-atlantic/
Here is actual observational data.
I am not a scientist but I think one problem with the new paper is a communications issue, namely the word resilient in the abstract. This has a certain scientific meaning, but to the public it says the AMOC will be just fine even with strong warming. The subsequent statements that the AMOC will weaken won’t matter to the public because they have that word resilient planted in their brain, and they WANT to believe everything will be fine.
Especially during times when things are judged based on appearance (headlines) instead of the actual conclusion and scientific process (consensus and how it is derived, what is lacking, overall opinion from the actual experts).
Chris, agreed. The following is a perfect example of headlines, with a media outlet miragenews.com reporting on the new AMOC study. Their headline reads :”AMOC Resilient Against Future Climate Warming:”,
https://www.miragenews.com/amoc-resilient-against-future-climate-warming-1415556/
The media have cherrypicked exactly the text they wanted from the study to possibly deliberately convey the impression the AMOC is in great health so theres no need to worry. Many people only read headlines as you mentioned. The popular definition of resilient conveys the impression that the AMOC is in great shape while the scientific meaning is more subtle. I’m not sure of the solution to the dilemma because the paper has not done anything wrong using the term resilient. Perhaps if they had explained what they meant in brackets this would have helped. I have enormous respect for scientists, but I feel need to better consider how the public and media will interpret their words,, and not hand the denialists ammunition.
Agree with respect to anything complex and analytic. But I actually find for most political-type/current event-type news ALL you need to read is the headline. Everything else is fluff or propaganda.
Easy to see the same effect here in posts from our resident deniers here as well.
“What previous studies have labelled an ‘AMOC collapse’ is now called ‘no collapse’.”
Seriously? (Shakes head.)
“It does not change the assessment of the risk and impact of future AMOC changes in response to human-caused global warming.”
Does that imply that there is a correlation with an increase in human-added CO2?
Ken Towe: “Does that imply that there is a correlation with an increase in human-added CO2?”
CO2 does not DIRECTLY drives AMOC. First – “the human added CO2” is countered in part by the natural CO2 uptake and increased removal via CO2-fertilization. The remaining increase in CO2 nonlinearly increases GMST, with the increase being amplified by positive feedbacks with various elements of the water cycle and albedo of ice and snow. The Arctic component of GMST rise is then nonlinearly translated into the increased melt of Greenland ice-sheet and reduction in ice formation. These are then transported around by surface currents, depending on winds. Then this transported signal, with added on top weather variability in the ocean south/east of Greenland – affects the amount of formed sea-ice. and the T and S of the resulting water (which is also affected by the changes in the T and S advected horizontally from other parts of the ocean), determines the changes in the density of surface water, and only then influences the volume of the water that is dense enough to sink, thus driving the thermohaline part of AMOC.
Knowing about these complexities, spatial and temporal variability, and nonlinearities of the involved multiple interactions – why would ANYONE even ask about a … linear correlation between AMOC and “human-added CO2”????
Expecting high-school statistics tools to provide any meaningful insight into AMOC – is like asking a microscope-repair technician whether they tried to use a 1-pound hammer you have provided them to fix the microscope.
Ignoring your insult. I never said anything about a direct or linear correlation. Human caused global warming is the result of oxidizing carbon that is putting at risk the future of AMOC.. If true why the comment?
Kein Kollaps des Golfstroms bis zum Jahr 2100 auf derstandard.at
https://www.derstandard.de/story/3000000259038/kein-kollaps-des-golfstroms-bis-zum-jahr-2100
With the headline transpayin english: “good news- no collaps of the AMOC”
Toujours la semiotique.
It’s surprising that until now, even on a blog like RC, nobody has thought to address the issue of how words are used in communicating science to the public, eh.
zebra: “ It’s surprising that until now nobody has thought to address the issue of how words are used in communicating science to the public”
Perhaps because the problem is not in your hobby-horse – definition of the words – but in the … psychology?
I don’t think Baker et al. had problems with definition of words – rather they have suffered from the selective blindness caused by the confirmation bias
– the authors MUST have known that AMOC is made of two different parts – the shallow wind-driven and the main-part driven by thermohaline conditions – the word thermohaline although not mentioned in their text – is in four of their references.
But they have ignored it – because their goal was to make their mark in science by becoming the paradigm changers – nobody would be interested in their paper, certainly not Nature – if they just confirmed what other people have been saying already for decades.
That’s why they ignored the part of their knowledge that was telling them otherwise, and that’s why they have ignored Feynman’s warning: “The first principle is that you must not fool yourself and you are the easiest person to fool.”
As for the editor(s) of Nature – they are not specialists – so they rely on the peer reviewers and since the reviewers didn’t flag it out – they went along with as strong a claim as they could – since the ability to recognize and publish the paradigm-shifting paper – is the primary consideration in evaluation of how good an editor you are. And with this goal in mind, you silence any doubts “ how comes that nobody else before has figured it out?” As they say in Poland: ” you don’t check the teeth [an indicator of health – P] of the gifted horse”.
Now why the third part of this mess, peer-reviewers, have missed it – I have no idea.
After all they have had nothing to gain, but a lot to lose – if they missed a massive and very consequential misrepresentation of the paper they reviewed – and they, the supposed gate-keepers of the good science, had allowed to slip it.
And they will be reminded of this failure forever – as the deniers will be using the paper the reviewers OKayed – to dismiss the dangers of climate change and to attack the credibility of climate science – any attempt to correct the public perception of the Baker et al. paper will be presented forever as the science establishment trying to silence/censor the scientist brave enough to challenge the climate change orthodoxy. Quite a burden to carry, even if they names are not known to the public.
It is ironic that the climate science deniers do use papers from genuine climate scientists, to bolster their case that climate science is invalid. Of course the deniers misquote the papers, misinterpret them or misrepresent their findings, but one would think the contradiction would prevent them from doing this. I suppose the message is: ‘Look, even the climate experts are now admitting that they were wrong!’
Rory, the point I’m raising (and have often raised) is that the way to counteract misinformation as you describe is to do a better job of communicating and educating the public.
That requires skill, and discipline in writing, and there is a real lack of that even in discussions (as here on RC) which are ostensibly aimed at readers who may be sincerely interested in improving their level of understanding, but with limited background.
I’ve given some examples/models on UV,
https://www.realclimate.org/index.php/archives/2025/02/unforced-variations-feb-2025/#comment-830339
In my experience, “the public” is quite capable of understanding and internalizing the important fundamentals. But there has to be a consistent use of (correct) basic terminology, and brevity/simplicity, and yes, repetition. Not filling the page or showing off how many words one knows.
And if anyone wants to challenge and distort such a presentation, they would have to challenge the basic physics, and established definitions. I’ve seen some pretty good “plain-language” sections on papers lately, but they seem to be in the minority.
Note: Stefan’s response to NCFM Eighty above is good, but that should be the norm in the form of an introduction. Don’t start talking to one’s peers right away.
Piotr: Please take your own advice. A judicious and hostility-free use of words would make what are often excellent points emerge from the welter of excess, rage (or at least anger), and self-certainty in your lengthy arguments and. condemnations. Please stop getting in your own light.
Real observational data, not a computer study, shows a 12% reduction in the abyssal limb of the AMOC.https://www.aoml.noaa.gov/atlantic-meridional-overturning-circulation-weakening-in-the-deep-sea-of-north-atlantic/
Stefan:
This response is slightly off-topic, but this instance of how climate science data are interpreted and then reported helped provoke the query, which is this:
how many physicists worldwide are actively working on climate change in all of its permutations and phenomenal realms (atmospherics, biospherics, cryospherics, hydrospherics, and lithospherics, to say nothing of chemistry, et cetera)? What might the total population (approximately) of physicists working directly on climate sciences in the world today be?
Considering the dynamics inherent to climate sciences, considering the challenges of employing consistent data sets and modeling, considering also the outright disputes in measurement and assessment (and explanation) that continue to occur, I begin to wonder whether we have quite enough physicists at work on tracking down the elusive climate data and whether enough physicists are engaged already so that even more disputes do not break out.
I’ve begun thinking of this outlay of “physicist resources” comparing the population of space sciences physicists (including astrophysicists) in all space science and space exploration and astronomy and cosmology domains with the population of physicists working across the distinct areas of the climate sciences. Are the numbers in the respective populations commensurate to the tasks, the challenges, and the threats entailed within “celestial” sciences versus “terrestrial” sciences?
Are enough physicists at work addressing the challenges, threats, and perils of Technogenic Climate Change? If not, have you or your colleagues at RealClimate any reason to think that the situation is changing so that a commensurate number of physicists will begin tackling climate sciences in requisite numbers within the next decade?
Sincerely,
Edward Burke
P. S. (of course)–will the promised advent and arrival of emerging AI tech help or hinder efforts of data collection and assessment and modeling going forward?
[Response: Interesting question. I am a physicist, so are many of my colleagues at the Potsdam Institute (in fact, even some working on climate economics have physics degrees). The number of papers published last year on the search term “climate change” is 56,000 according to Web of Science. The number of scientists involved will be of the same order of magnitude (say, on average each scientist published 3 papers that year, and each paper has 3 authors). If only a few percent of these scientists are physicists, there will be thousands of physicists around the world working on climate change. But it would be nice to see a more detailed analysis. -Stefan]
Edward, I appreciate this question in the context of broader physics. The majority of climate scientists working on this topic follow the line of conventional wisdom and build on what everyone else is doing. OTOH, physicists are often a different breed and will go off on tangents and explore models that have little to do with the mainstream GCMs.
For instance, there are a handful of physicists that are working the category of topology applied to climate dynamics. There’s a group comprised of physicists from Brown U and universities in France. And there’s this recent paper, which is unfortunately pretty vague and they don’t cite the other work:
“Topology shapes dynamics of higher-order” networks” https://pure.unamur.be/ws/portalfiles/portal/107091767/topology_shapes_dynamics_short_v3.pdf
This falls under the field of fluid dynamics, which very few physicists even get to study as part of their education, apart from understanding the Bernoulli principle. This is a huge gap. Geoff Vallis, who has written extensively on geophysical fluid dynamics posted this https://bsky.app/profile/gkvallis.bsky.social/post/3lj433goiz22h
“Important to note that our conclusions depend not just on the results of model integrations, but on our understanding of the mechanisms involved. Still, little is certain in this business, and it does not mean the risk of collapse is not there, even if we think it is unlikely.”
Machine learning will be a great equalizer, as it is being increasingly used by climate scientists — who will not necessarily not know how to interpret the results, so that they will have to task physicists to figure out what it all means.
A really encouraging example (behind paywall, I guess):
https://www.sueddeutsche.de/wissen/atlantik-stroemung-abschwung-klima-kipppunkte-europa-li.3208350?reduced=true
Headline basically reads “Even a weakening of the Atlantic Circulation can be fatal”
And what follows is a really, really thorough and informed article including a good summary of potential effects. I actually felt sort of dizzy with excitement after reading, because I braced for the usual misrepresentation and was presented with a real gem of an article
The authors’ response to Stefan Rahmstorf’s blog post:
Our study shows that under extreme scenarios, 3 out of 34 models simulate the AMOC weakening to just below 5 Sv (often considered a collapse threshold) after 100 years. Most models project an AMOC strength between 5 and 12 Sv, with a few exceeding 12 Sv. However, it’s important to note that these are extreme climate change experiments—not what we’d expect under more realistic conditions. Under the high-end “realistic” SSP585 scenario (https://agupubs.onlinelibrary.wiley.com/doi/full/10.1029/2023GL103381), the minimum AMOC strength by 2100 across 27 models is about 7 Sv, with an average decline of 44%.
Across both extreme and realistic scenarios, our analysis reveals that wind-driven upwelling in the Southern Ocean is essentially the only AMOC upwelling pathway that remains active in most models. Since the Pacific overturning circulation (PMOC) doesn’t develop under realistic forcings, the sustained wind‐driven upwelling in the Southern Ocean maintains a stronger AMOC. This finding reinforces our confidence that the AMOC “stability” seen in these models is grounded in robust, physical mechanisms. Our conclusion that the AMOC is unlikely to collapse this century is drawn from these realistic forcings—i.e., based on what we expect to happen; though it is important to note that “unlikely” isn’t the same as “impossible”—the risk is real.
Stefan mentions in his blog that our study “does not change the assessment of the risk and impact of future AMOC changes in response to global warming”. After discussing this further on Bluesky, he confirmed that his view aligns with the IPCC’s medium confidence that the AMOC will not collapse before 2100. This confirms that we are more aligned than it seems at first glance. Our study provides additional evidence in support of this statement.
While it’s long been recognised that wind‐driven upwelling contributes to the AMOC, our work shows that in future scenarios, it becomes the primary AMOC upwelling mechanism that remains active, unlike upwelling in the Pacific. Our method separates these pathways, and consistently across all models, the wind‐driven upwelling in the Southern Ocean is what keeps the AMOC running, even under extreme forcing.
We believe it’s not valid to completely separate the “thermohaline” component from the wind‐driven part of the circulation. Even under extreme forcing, deep and dense water formation in the North Atlantic continues (albeit at reduced rates and with a shifted location). This deep water formation is especially evident under realistic forcing scenarios, despite the wind‐driven upwelling being the dominant upwelling pathway of the AMOC.
Finally, when we conclude that an AMOC collapse is unlikely this century, we are referring to a collapse as defined in several other studies —not a complete cessation of circulation to zero. In our paper, we use “collapse” to mean zero circulation when referring to extreme scenarios, but “collapse unlikely this century” refers to the broader definition used in other studies. A weakening AMOC is expected and poses significant climate risks, but a collapse isn’t what the CMIP6 models indicate under realistic forcings.
[Response: Thank you Jonathan. We don’t disagree on the science, I think my article here makes that clear upfront, and I told the Science Media Centre that it is a valuable study. My concern is about the framing in the article title and the press releases – which have led to a lot of misleading media articles – and particularly misleading headlines even where the articles were balanced. I have spoken to quite a few colleagues working on AMOC issues during this week, and comments on that framing typically ranged from “how did this title get past peer review?” to “shocking”. Stefan]
J. Baker: “ We believe it’s not valid to completely separate the “thermohaline” component from the wind‐driven part of the circulation.”
Why not valid? One is shallow, driven by winds and as such – UNLIKELY to change without MAJOR reorganization of the winds. The other is much deeper and thicker, driven not by wind, but by changes in T and S, and such – vulnerable to the climate change. So why would not clearly separate them?
The differences in the seawater needed to slow down the thermohaline (THC) part of AMOC – are not very large, so even a small increase in T or a small decrease in S, may easily change the rate of NADW formation. This makes THIS part of AMOC uniquely sensitive to the climate change: to less winter cooling, and, more importantly given that the density changes in polar regions are dominated primarily by S and not by T, sensitive to the decreases in S from the Greenland icesheet melt and from reduced sea-ice formation.
So given the different mechanisms, and very different vulnerability to climate change, different volumes and different time scales involved – what applies to one does not necessarily applies to the other. And the core of Stefan’s criticism is your conflating of the two: you took your findings of the resiliency of the wind-driven part of AMOC, and phrased it as if this was reflective of the ENTIRE AMOC, i.e. as if the other thermohaline part of AMOC didn’t exist or wasn’t important (the word “thermohaline” appears in your article – only in (a few) references) or as if, despite the very different mechanisms and vulnerability, for some reason responded in the identical way.
In a societally-important field of science such as climate change, one that can inform the civilization’s response to an existential threat, and as such – is a target of deliberate, ideologically-driven, misrepresentation – the scientists have the responsibility to leave as little room for misunderstanding or misrepresentation of their results as possible.
By this measure, seeing the titles from a range of media from different countries (see posts above) – you and your coauthors have failed spectacularly,
If even a non-denier, left-leaning, paper (“Gazeta Wyborcza”) writes:
“ Let’s not let ourselves run amok. New study on the future of the Gulf Stream ”
Global warming does not mean that Europe is cooling, scientists write in Nature. […] You probably remember the headlines from recent years: “The Gulf Stream is weakening”, “A threat to the Earth”, “The Gulf Stream may disappear”. Where does this hysteria come from?”
then you can imagine how your article will be used in the media owned/funded by the fossil fuel corporations and petro-states.
Hi Stefan, an interesting article and it seems pretty clear we need to do everything we can to prevent the AMOC collapsing.
I came across a study you commented on (https://fediscience.org/@rahmstorf/113119393622398266) that the Telegraph is jumping on as proof the AMOC is stable (https://www.nature.com/articles/s41467-024-51879-5).
Since the paper is about the Florida Current and later in the paper it discusses the effect on the AMOC trend which still appears significantly negative, is the point that the FC is just a small part of the AMOC so not particularly indicative?
Thanks for your updates here at realclimate, much appreciated
Nature does not like discontinuities and imbalances. The gulf stream exists because there is too much energy at the equator compared to the poles. The gulf stream stopping would mean that a large share of this excess heat remains at the equator. As it builds up, something has to take over and move it towards the poles. Nature often does that continuously. See for example in multiphase flow in pipes. The flow regime may change, but the pressure drop is continuous and quite smooth. But models missing phenomena may make it look like there is a discontinuity (which the gulf stream stopping would be). Now there could be transient hiccups on the way to a new regime, that may be disruptive to Europe and Africa. But I think this explanation that the winds will take over for the circulation sounds likely: this is Nature’s way to keep things smooth.
Die Schlagzeile einer Zeitung in Österreich treibt es auf die Spitze: “Die gute Nachricht: Kein Kollaps des Golfstroms bis zum Jahr 2100”
https://www.derstandard.at/story/3000000259038/kein-kollaps-des-golfstroms-bis-zum-jahr-2100
Stefan, I’m glad to hear we don’t disagree on the science—though, of course, scientific disagreements aren’t a bad thing when they’re based on fair and accurate communication. My concern is with how you’ve framed our study as not adding anything new. While the experiments themselves may be the same, our analysis demonstrates that robust physical mechanisms may explain AMOC “stability” in models—something that, to my knowledge, hasn’t been clearly shown before.
I understand your concerns about whether models might be overstable, which is a valid question. However, our study suggests this may not be the case—though, of course, further research is needed.
Additionally, your article doesn’t make it clear that while our experiments involve extreme climate change scenarios, our key message—that the AMOC is unlikely to collapse (i.e., to around 5-7 Sv) this century—is based on what is expected in the real world, i.e., under realistic forcings. If that wasn’t communicated clearly in our paper, I’ll check, but that is the case.
I agree that there’s no direct conflict between our findings and those in your preprint, and I wouldn’t necessarily comment publicly even if there were. However, I felt that you downplayed our findings here—that’s my main objection. With your large following, I felt it was important to make our findings clear. You are, of course, entitled to your opinion, but I will defend our research, just as I’m sure you would defend yours.
Regarding the title of our paper, it is factual, and I don’t see an issue with it. Only 3 out of 34 models analysed have an AMOC weaker than 5 Sv after 100 years of extreme forcing—that is what led to the title. As I mentioned before, I don’t write the headlines. In my comms, I believe I have consistently communicated that the AMOC is very likely to weaken, and that this, along with broader climate change impacts, presents significant challenges.
I appreciate your thoughtful response and look forward to discussing our research further at EGU—outside the public spotlight.
Jonathan Baker, thanks for the interesting commentary. You said: “Regarding the title of our paper, (Continued Atlantic overturning circulation even under climate extremes), it is factual, and I don’t see an issue with it.”
Yes its factual, but in my view it’s an unfortunate title because many people may interpret it to mean the AMOC just keeps flowing so there will be no problem. A better title might have been: “Continued weak Atlantic circulation even under climate extremes”, or “continued but reduced Atlantic circulation…” Just one more word makes a difference.
I know there is a desire for economy of words in titles and the content of research papers, but sometimes that has unfortunate consequence of the media and denialists being able to the downplay the severity of what’s happening. IMO James Hansen is one researcher who is careful with titles and words and also includes good background information in his papers that minimises the risk of people downplaying things.
Thanks for your work.
For CMIP6 models, a pre-publication by David Bonan et al. “Constraints imply limited future weakening of Atlantic meridional overturning circulation”, indicates that models with the largest decreases in AMOC are not supported by observational constraints (due to stratification bias). I think this supports your conclusions.
https://www.theguardian.com/environment/2025/feb/26/total-collapse-of-vital-atlantic-currents-unlikely-this-century-study-finds