19 ms·
A forthcoming collapse of the Atlantic meridional overturning circulation
- dvh 3y agoModel Intercomparison Project (CMIP) model simulations suggest that a full collapse is unlikely within the 21st century.
- Mvhsz 3y agoIn reference to the cmip model, the article says: > There are, however, model biases toward overestimated stability of the AMOC, both from tuning to the historic climate record, poor representation of the deep water formation, salinity and glacial runoff. The article goes in to say why they disagree with the cmip assessment, and rather believe it could happen “around mid century” of the current century.
- notamy 3y ago> Predictions based on observations rely on detecting early-warning signals, primarily an increase in variance (loss of resilience) and increased autocorrelation (critical slowing down), which have recently been reported for the AMOC. Here we provide statistical significance and data-driven estimators for the time of tipping. We estimate a collapse of the AMOC to occur around mid-century under the current scenario of future emissions. The abstract also says that the collapse would impact the north Atlantic region, but in what way? Assuming the prediction is accurate, what changes could we expect to see in that scenario? Wikipedia suggests that temperatures in northern Europe would drop significantly + sea levels would rise, but is that all? https://en.wikipedia.org/wiki/Atlantic_meridional_overturning_circulation https://en.wikipedia.org/wiki/Atlantic_meridional_overturnin...
- coremoff 3y agoIf nothing else, the UK would more closely resemble central Europe, as I understand it - colder winters, hotter summers
- richardwhiuk 3y agoGiven a full collapse, wouldn't the UK resemble northern Canada?
- pvaldes 3y agoThere is a good way to see the problem in a second Think about New York, is at 40 degrees N latitude. This means that if NY would be in the Atlantic coast of Europe would fall in Portugal! a little North to Lisbon! (38ºN). Sometimes Is easy to forget that NY is "Southern Europe" league. Southern than the North Coast of Spain. Now lets see Quebec (53ºN). Well, London is 51ºN. Without the sea current bringing hot tropical water, London should have practically the same climate than Quebec, and 90% of UK is higher than London, so would enjoy the full whole Canadian winter experience.
- deleted 3y ago[deleted]
- hathchip 3y agoBut the West Coast of North America is has milder winters than the East Coast, which has milder winters than the center. Shouldn't we expect London to end up with a similar climate as somewhere on the West Coast of Canada at the same latitude?
- pvaldes 3y agoProbably Yes, because NY is also warmer that it should be. It receives still part of this warm water before the current turns toward east, plus it has also a heath-island effect created by cars and houses. So if you remove this effect for both Europe and US, NY should be much colder than it is currently (And most of Europe also).
- saltcured 3y agoI think the hard part of this is predicting how the global jet stream and polar vortex winds might change in response to disruption of the Atlantic currents. It already changes for North America in response to the Pacific subtle temperature oscillation we call El Nino / La Nina. The proximity to the ocean and the general westerly winds of the mid latitudes mean that the west coast gets a moderating marine influence. The cold ocean surface provides us "air conditioning" in summer and yet is also a mild "heater" in winter, helping keep coastal air above freezing temperatures. But, this general background pattern is regularly disrupted by large high and low pressure systems that wander through the region and give us our weather of storms, cold snaps, and heat waves. These cyclonic systems can both carry a somewhat distinct air mass inside them and also disrupt the normal westerly surface flow. And the jet stream is largely in control of steering these systems, making them track further north or south or even helping them stall out temporarily in their generally eastward course.
- troupo 3y ago> Wikipedia suggests that temperatures in northern Europe would drop significantly + sea levels would rise, but is that all? Depends on the drop and the rise. Open a world map, and draw parallels passing where large Northern European cities are. [1] E.g. Canada's Montreal roughly corresponds to Paris. [1] Or this gif from reddit: https://preview.redd.it/dm7xwsmp3aa81.gif?format=mp4&s=a16738d03fdcbbbf1373621cab50d55d178fb7c3 https://preview.redd.it/dm7xwsmp3aa81.gif?format=mp4&s=a1673...
- snowwrestler 3y agoIreland and Great Britain are at about the same latitude as Labrador in Canada, but benefit from heat transported across the North Atlantic from the Caribbean by warm water. Absent the current that is transporting that warm water, one would expect the GB climate to more closely resemble Labrador’s. In other words, much colder.
- fmstack 3y agonot gonna lie, a scenario where a big nasty effect of climate change pastes Europe first might make the powers that be wake up to the impending disaster faster. For the folks with the big money one death in Europe might be more shocking than 100 deaths in India.
- RandomLensman 3y agoIf Europe expends much more energy to deal with cold and food production in the cold not sure that would help the world much.
- IKantRead 3y agoThe trouble with climate change has always been that by the time you notice the "big nasty effect" it's already too late to prevent catastrophe. To be clear, it's never too late to improve our fate, but by the time something like the AMOC shutting down destroys Europes climate, you've already signed up for an incredible amount of climate pain. Maybe such an event will wake us up enough to prevent out right extinction, but if this happened the collapse of industrial civilization would be virtually guaranteed.
- kinjba11 3y agoIsn't that what this and other papers say - that AMOC is doomed to collapse, it's just a matter of time? I'm not sure I'd equate AMOC collapse to industrial civilization collapsing. My understanding with climate change is that we have signed up for a lot already, but much more is on the way if we don't make big changes faster. Humanity is a crisis-motivated species. The trouble with climate change is the effects so far have nearly no impact on power. If AMOC were to shut down in 2030 devastating Europe's economy, that could be the wake-up call to everyone to actually stop fossil-burning ourselves to doom for short-term conveniences.
- ridgeguy 3y agoLast sentence in the Abstract: "We estimate a collapse of the AMOC to occur around mid-century under the current scenario of future emissions."
- aport 3y agoFurther in the paper "The mean of the bootstrapped estimates of the tipping time is 〈tc〉 = 2050, and the 95% confidence interval is 2025–2095."
- digdugdirk 3y agoWhoof. Those are some spooky error bars.
- mikeyouse 3y agoEspecially since almost every "long term" problem seems to be happening in the much shorter term than was originally predicted. Not great!
- stoneman24 3y agoClimate change was sometimes dismissed (or reduced) by saying that’s it an issue for our grandchildren. With those error bars (NOW to +40 years), the immediate nature of the problem and the required response should hit home. Given recent heatwaves, I think nature is starting to hit us with the clue stick. I hope the important people are listening.
- mschild 3y agoAn article from livescience.com that may be worth a read. TLDR: if slowdown occurs, temperatures could drop by 5C in Europe and North America. What a 5C drop actually looks like they don't say. https://www.livescience.com/planet-earth/climate-change/gulf-stream-current-could-collapse-in-2025-plunging-earth-into-climate-chaos-we-were-actually-bewildered https://www.livescience.com/planet-earth/climate-change/gulf...
- gabereiser 3y agoAt this point we can’t even manage 0.1C, how are we going to get 5C?
- kneebonian 3y agoSo if this continues it will result in a 5C drop in temprature across North America and Europe? Am I understanding this correctly. Which for reference a 5C drop should mean that New York is covered in glacier according to this source https://xkcd.com/1732/ https://xkcd.com/1732/
- i_am_jl 3y agoNYC was covered in a glacier the last time the global average temperature was 5C cooler. That's not the same thing as Europe and NA cooling by 5C.
- AbrahamParangi 3y agoWhile strictly true, that doesn't mean 5C cooling wouldn't eventually result in NYC under ice.
- postmortembees 3y agoYou've misunderstood the source. While temperatures locally will drop by 5C, the global average will not. That chart shows global averages, ie, the whole world was 5C colder. NY might have been much, much colder than that.
- jmclnx 3y ago
- rcarr 3y agoAnyone else think that all these predictions are going to happen sooner rather than later in terms of the given prediction range? I can't help but think that a study focussing on a specific area like this one, antarctic sea ice, wildfire predictions etc must only be able to take so many variables into account and that second order effects, third order, fourth order and beyond from other climate subsystems are going to compound and significantly accelerate the timeline.
- onlyrealcuzzo 3y agoThere is some P that all those unknown variables act in opposite directions, rather than the same direction. My guess is it's pretty close to 50% - otherwise they probably would've studied those variables. But predicting the future is basically impossible. So who knows. We're all basically guessing.
- callalex 3y agoNo, the entire field of climate science is not “basically guessing”. That’s not what scientific study is.
- post-it 3y agoOh absolutely. Environmental scientists are very conservative and anti-alarmist with their predictions, and every successive generation of derived data skews towards the more conservative end.
- Brusco_RF 3y agoSatire?
- empyrrhicist 3y agoNo, this has been pretty well documented and reported. https://www.scientificamerican.com/article/climate-science-predictions-prove-too-conservative/ https://www.scientificamerican.com/article/climate-science-p...
- igravious 3y agoIf the authors of the paper are reading this forum I bet them €10,000 (in 2023 money) that this event (collapse of the AMOC) will not occur this century.
- commandlinefan 3y agoI bet €10,000 that the government will use this as an excuse to raise our taxes anyway.
- post-it 3y agohttps://xkcd.com/1132/ https://xkcd.com/1132/ When the AMOC collapses, they may not have much use for your €10,000.
- jwilber 3y agoWhy stop there? I know plenty of PhD’s who would love to make bets with you about topics in their field - probably easy money for a smart guy like you!
- oceanthrowaway 3y agoI’m a physical oceanographer. While I have only skimmed this article I would like to make two quick comments. 1) The AMOC is one of the most studied parts of the world ocean and predictions about its collapse have been made since Stommel in 1961. I think in general any study on its imminent collapse should be taken with a grain of salt and it would be wise to wait for further replication and the consensus of the community. You can google AMOC collapse and find articles stretching back decades. 2) This may be my bias a dynamacist but I am skeptical of purely statistical models of AMOC collapse. The AMOC is complex and trying to predict the time of a complete collapse is a significant simplification (especially when, as the authors note, a slowdown rather than shutdown of the AMOC seems more likely from our current understanding). Nevertheless this is a very interesting study and contribution to the field. Edit: @abathur posted a wonderful link below that I wanted to spread further: https://www.sciencemediacentre.org/expert-reaction-to-paper-warning-of-a-collapse-of-the-atlantic-meridional-overturning-circulation/ https://www.sciencemediacentre.org/expert-reaction-to-paper-...
- retrocryptid 3y agoAre you comparing Stommel's Box model to Bower's recent work? I would argue the latter is more "expressive" though yes, it depends on measurements we weren't collecting in the 60s.
- oceanthrowaway 3y agoNo I am just noting that the AMOC bistability literature is decades long.
- bhouston 3y agoSo is the climate change literature, it stretched back decades before we had concrete evidence that it was happening. Just because something is long predicted to be a risk by experts in a field, doesn't mean its likelihood of happening goes down. I right read about AMOC back in 1997 while in university. It was fascinating and frightening back then. Still relevant today. It would be sad if it did actually end up happening in my lifetime, but humans are notoriously bad at reacting to bad things that might happening in the future - https://en.wikipedia.org/wiki/Tragedy_of_the_commons https://en.wikipedia.org/wiki/Tragedy_of_the_commons. We tend to only really react once the bad thing has happened.
- nprateem 3y agoIt's about time we start charging current and former heads of state for dereliction of duty and crimes against humanity.
- ShakataGaNai 3y agoPart of the challenge of this climate information is that it's so bloody complicated. Yes, Nature is doing a scientific write-up, but even reading the abstract all I get is "severe impacts on the climate in the North Atlantic region". What does that mean? Ok, well, why don't I at least look up the AMOC in the first place. Quick dash over to wikipedia [1] and I find out that... > The Atlantic meridional overturning circulation (AMOC) is part of a global thermohaline circulation in the oceans and is the zonally integrated component of surface and deep currents in the Atlantic Ocean. While I am not a scientist, I consider myself fairly well-read and not an idiot. But when the first sentence of a Wikipedia article needs an ELI5 translation by ChatGPT... you know you're in for a reading adventure. (But by the 3rd paragraph Wikipedia has a relatively understandable "what if this goes wrong" breakdown) [1] https://en.wikipedia.org/wiki/Atlantic_meridional_overturning_circulation https://en.wikipedia.org/wiki/Atlantic_meridional_overturnin...
- bullen 3y agoSo what would the consequences be? ~3-5 degree drop in temperature at the coasts?
- sieste 3y agoSomething on the same order of magnitude as projected global temperature increase. That's why you see a white/blue blob in the North Atlantic on maps of temperature trends. https://commons.wikimedia.org/wiki/File:NCDC_temperature_trend.png https://commons.wikimedia.org/wiki/File:NCDC_temperature_tre...
- whalesalad 3y agoyoutube has some great visual references for understanding the size and significance of this circulation. - https://www.youtube.com/watch?v=LnV9oq_AewI https://www.youtube.com/watch?v=LnV9oq_AewI - https://www.youtube.com/watch?v=j2ETr6X1lOk https://www.youtube.com/watch?v=j2ETr6X1lOk suffice to say the implications of this system changing will be felt globally.
- abathur 3y agoI found a lot of helpful context for understanding the research (and the implications if its forecast proved accurate) in https://www.sciencemediacentre.org/expert-reaction-to-paper-warning-of-a-collapse-of-the-atlantic-meridional-overturning-circulation/ https://www.sciencemediacentre.org/expert-reaction-to-paper-...
- snowwrestler 3y agoOne of the predictions related to global warming that seems to surprise people is that most of the predicted sea level rise is attributed to the thermal expansion of warmer sea water. So when we think about major changes in how the ocean absorbs and distributes heat, we’re also thinking about how sea level will change in certain areas vs others. If the ocean starts storing a lot more heat around Cuba than Great Britain, Cuba will experience more sea level rise than Great Britain does.
- philipkglass 3y agoI don't think that is true. The oceans around Cuba and Great Britain are not separate bodies of water. Volumetric expansion from heating gets flattened out across all connected bodies of water by gravity. You could see differences of geography in how much different lakes expand, though.
- Mordisquitos 3y agoI don't know. Consider that a given mass of water would undergo the same gravitational force regardless of whether it is colder/denser/smaller/lower or whether it is hotter/less-dense/larger/higher. Also, as an analogy, consider how much the tidal range [0] varies between areas of the ocean which are absolutely connected as a single body of water. Note particularly the contrast between tides in the Mediterranean and the Atlantic Ocean at large on each side of the Iberian Peninsula, even though they are totally connected through the Straight of Gibraltar. [0] https://en.wikipedia.org/wiki/Tidal_range https://en.wikipedia.org/wiki/Tidal_range
- snowwrestler 3y agoThis isn’t hypothetical, water temperature is already known to be one factor in deviations of regional sea level from global sea level. If the conditions that create the heat differential are persistent, the height difference will persist as well.
- braaannigan 3y agoI've got a background in this field and I am very surprised to see this published in Nature. The model presented is purely statistical with no representation of the underlying physics. When we are dealing with a phenomenon that is driven by well-understood physical laws (e.g. geophysical fluid dynamics, radiation physics etc) then these physical models are the most reliable basis for prediction. When I say physical models here by the way I'm referring to physically-based mathematical models as well as numerical models. It seems that the authors have done a good job in developing their model. My issue is with Nature deciding to publish it. If this paper was not published in Nature it would receive little attention within or without climate science - in fact many such statistical models are published each year without much comment. However, Nature have published a paper that I think many ocean scientists would feel draws dramatic conclusions from a weak basis but will now inevitably draw much more attention than more insightful papers. MIT professor Carl Wunsch accused Nature in 2010 of near-tabloid science with a tendency towards sensational papers built on weak foundations. However, I've felt that Nature's choice of publications on climate in recent years has been high quality. This paper feels like a big step-down from that standard.
- gwerbret 3y agoThe publication is in Nature Communications, which is a bit of a different (lesser) beast than Nature.
- braaannigan 3y agoThanks for pointing this out, I missed that
- CamperBob2 3y agoThis is becoming a perennial refrain in HN stories based on scientific papers. ("Oh, wait, this dubious study or lazy meta-analysis isn't really appearing in Nature, it's some other publication to which Nature has whored out their name and credibility.") It sounds like the 150-year-old scientific journal of record has been taken over by private equity, or by MBAs with KPIs to optimize.
- irrational 3y agoSo, the current stops and things get colder in Europe, but they have been having serious heat wave issues each summer. Will things be worse in the winters, but better in the summers if the current did stop?
- dboreham 3y agoProbably worse than the sunbathing conditions changing: some crops that can currently be grown in, say, Scotland, wouldn't grow there any longer.
- ke88y 3y agoThe climate is an extremely complicated system. The first order effect of AMOC collapse might be cooler European summers, but eventual build-up of ice could effect atmospheric systems leading to hotter summers. Of course, more or less comfortable summers might not matter much with half of Europe starving to death from crop failure.
- mym1990 3y agoThis has been on my mind this past week(and is only lightly tangential)...but would we be able to observe adaptations being made by plants/animals/ecosystems on a timescale of years or decades...to the changing climate? Humans will be playing mental gymnastics and politics for quite a while before any true changes to move the needle are made...but all other biological things can just make the adaptations...given enough cycles to recognize that something is different(the last 3 seasons were much wetter or colder or hotter, etc...). I imagine these adaptations could be earlier/later migrations, reproduction habits, hibernation patterns, food gathering. Not necessarily changes in DNA.
- autoexec 3y ago> but all other biological things can just make the adaptations That only works with enough time, and changes are happening too quickly. Here's how animals have been adapting in just the last 50 years: https://phys.org/news/2022-10-wildlife-populations-plunge-wwf.html https://phys.org/news/2022-10-wildlife-populations-plunge-ww...
- bathMarm0t 3y agoIt's already being observed. Bird migrations have been happening earlier/later, and ranges of birds have increased. I'm sure the same thing is happening for whales / ocean animals. According to this one[1], they're adapting by leaving later, and flying faster/taking less breaks to make up for the lost time. The result being that less of them make it to the breeding grounds (6% decrease in survival rate). [1] https://news.cornell.edu/stories/2023/04/risky-strategy-helps-migratory-birds-offset-climate-change https://news.cornell.edu/stories/2023/04/risky-strategy-help...
- pvaldes 3y agoMigration in terrestrial animals has been blocked. By us. Nobody expects reindeer being allowed to pass the Holidays in France. Birds can fly. European terrestrial big mammals used to have extensive migrations like those in Africa. Not possible anymore with all the cities, agriculture and highways.
- TSiege 3y agoUnlocked WaPo article for the lay person https://wapo.st/3q6uuGQ https://wapo.st/3q6uuGQ
- fwungy 3y agoIn the big picture of the geologic time scale we are at risk for an ice age soon enough. The normal state of the Earth is cold and icy, but still habitable, perhaps barely. No one is sure why the ice ages happen, the most popular theory is that it's caused by perturbations in Earth's orbit.
- Tokkemon 3y agoTime to call Dennis Quaid and get to the NYPL. Is Roland Emmerich available?
- anjel 3y agoThis article makes no mention of and has me wondering if this model contemplates undersea hydrate and permafrost methane release and its effects on the climate slope? Or is it limited to what's already taken place and excluding potential accellerant events?
- marcfalk 3y agoDon't wanna downplay the seriousness of an ocean current collapse, however, articles covering this Danish study seems to grab the "we're gonna die soon"-angle by default. Danish media has found other scientists that do not quite accept the conclusion based on methods used. E.g. this abstract summarized by ChatGPT: > Climate scientist Steffen Malskær Olsen (specializing in ocean currents at the National Center for Climate Research under DMI) questions the predictions made by Peter Ditlevsen and Susanne Ditlevsen (authors of the study) about a potential collapse of thermohaline circulation. He cites limited data and uncertainty about the correlation between surface temperatures in the Northwest Atlantic and the thermohaline circulation as main concerns. Despite this, he acknowledges the study's importance for demonstrating the potential of advanced mathematical models in predicting climate phenomena. He believes that the IPCC's prediction, which deems a collapse highly unlikely, remains the most reliable. Peter Ditlevsen accepts this uncertainty, arguing they are working with the best data currently available. (https://nyheder.tv2.dk/klima/2023-07-25-danske-forskere-med-opsigtsvaekkende-klimastudie-danmark-kan-blive-helt-forandret-om-faa-aar https://nyheder.tv2.dk/klima/2023-07-25-danske-forskere-med-...)
- deleted 3y ago[deleted]
- bedhead 3y agoAlways some prediction of doom, yet the world keeps spinning and everything is magically always fine.
- swyant 3y agoSome additional useful context from RealClimate: https://www.realclimate.org/index.php/archives/2023/07/what-is-happening-in-the-atlantic-ocean-to-the-amoc/ https://www.realclimate.org/index.php/archives/2023/07/what-...
- blondie9x 3y agoThe worst part of climate change is our response. As world conditions worsen we burn more fossil fuels to simulate cooling/heating. It's a positive feedback loop. The more intense the summers get, and the cold snap of winter, the more fossil fuels we need, which then worsens further worsens the greenhouse gas effect. Then we need more fossil fuels on more days and so on. We aren't striving to consume less but to instead create green illusions and box ourselves in virtual reality or simulations. Maybe the simulation technologists say we are in is actually the one we focus on creating as Earth deteriorates more from our over-consumed lives.