For various reasons I’m motivated to provide an update on my current thinking regarding the slowdown and tipping point of the Atlantic Meridional Overturning Circulation (AMOC). I attended a two-day AMOC session at the IUGG Conference the week before last, there’s been interesting new papers, and in the light of that I have been changing my views somewhat. Here’s ten points, starting from the very basics, so you can easily jump to the aspects that interest you.
1. The AMOC is a big deal for climate. The Atlantic meridional overturning circulation (AMOC) is a large-scale overturning motion of the entire Atlantic, from the Southern Ocean to the high north. It moves around 15 million cubic meters of water per second (i.e. 15 Sverdrup). The AMOC water passes through the Gulf Stream along a part of its much longer journey, but contributes only the smaller part of its total flow of around 90 Sverdrup. The AMOC is driven by density differences and is a deep reaching vertical overturning of the Atlantic; the Gulf Stream is a near-surface current near the US Atlantic coast and mostly driven by winds. The AMOC however moves the bulk of the heat into the northern Atlantic so is highly relevant for climate, because the southward return flow is very cold and deep (heat transport is the flow multiplied by the temperature difference between northward and southward flow). The wind-driven part of the Gulf Stream contributes much less to the net northward heat transport, because that water returns to the south at the surface in the eastern Atlantic at a temperature not much colder than the northward flow, so it leaves little heat behind in the north. So for climate impact, the AMOC is the big deal, not the Gulf Stream.
2. The AMOC has repeatedly shown major instabilities in recent Earth history, for example during the Last Ice Age, prompting concerns about its stability under future global warming, see e.g. Broecker 1987 who warned about “unpleasant surprises in the greenhouse”. Major abrupt past climate changes are linked to AMOC instabilities, including Dansgaard-Oeschger-Events and Heinrich Events. For more on this see my Review Paper in Nature.
3. The AMOC has weakened over the past hundred years. We don’t have direct measurements over such a long time (only since 2004 from the RAPID project), but various indirect indications. We have used the time evolution of the ‘cold blob’ shown above, using SST observations since 1870, to reconstruct the AMOC in Caesar et al. 2018. In that article we also discuss a ‘fingerprint’ of an AMOC slowdown which also includes excessive warming along the North American coast, also seen in Figure 1. That this fingerprint is correlated with the AMOC in historic runs with CMIP6 models has recently been shown by Latif et al. 2022, see Figure 2.
Others have used changes in the Florida Current since 1909, or changes in South Atlantic salinity, to reconstruct past AMOC changes – for details check out my last AMOC article here at RealClimate.
4. The AMOC is now weaker than any time in the past millennium. Several groups of paleoclimatologists have used a variety of methods to reconstruct the AMOC over longer time spans. We compiled the AMOC reconstructions we could find in Caesar et al. 2021, see Figure 3. In case you’re wondering how the proxy data reconstructions compare with other methods for the recent variability since 1950, that is shown in Caesar et al. 2022 (my take: quite well).
5. The long-term weakening trend is anthropogenic. For one, it is basically what climate models predict as a response to global warming, though I’d argue they underestimate it (see point 8 below). A recent study by Qasmi 2023 has combined observations and models to isolate the role of different drivers and concludes for the ‘cold blob’ region: “Consistent with the observations, an anthropogenic cooling is diagnosed by the method over the last decades (1951–2021) compared to the preindustrial period.”
In addition there appear to be decadal oscillations particularly after the mid-20th Century. They may be natural variability, or an oscillatory response to modern warming, given there is a delayed negative feedback in the system (weak AMOC makes the ‘cold blob’ region cool down, that increases the water density there, which strengthens the AMOC). Increasing oscillation amplitude may also be an early warning sign of the AMOC losing stability, see point 10 below.
The very short term SST variability (seasonal, interannual) in the cold blob region is likely just dominated by the weather, i.e. surface heating and cooling, and not indicative of changes in ocean currents.
6. The AMOC has a tipping point, but it is highly uncertain where it is. This tipping point was first described by Stommel 1961 in a highly simple model which captures a fundamental feedback. The region in the northern Atlantic where the AMOC waters sink down is rather salty, because the AMOC brings salty water from the subtropics to this region. If it becomes less salty by an inflow of freshwater (rain or meltwater from melting ice), the water becomes less dense (less “heavy”), sinks down less, the AMOC slows down. Thus it brings less salt to the region, which slows the AMOC further. It is called the salt advection feedback. Beyond a critical threshold this becomes a self-amplifying “vicious circle” and the AMOC grinds to a halt. That threshold is the AMOC tipping point. Stommel wrote: “The system is inherently frought with possibilities for speculation about climatic change.”
That this tipping point exists has been confirmed in numerous models since Stommel’s 1961 paper, including sophisticated 3-dimensional ocean circulation models as well as fully fledged coupled climate models. We published an early model comparison about this in 2005. The big uncertainty, however, is in how far the present climate is from this tipping point. Models greatly differ in this regard, the location appears to be sensitively dependent on the finer details of the density distribution of the Atlantic waters. I have compared the situation to sailing with a ship into uncharted waters, where you know there are dangerous rocks hidden below the surface that could seriously damage your ship, but you don’t know where they are.
7. Standard climate models have suggested the risk is relatively small during this century. Take the IPCC reports: For example, the Special Report on the Ocean and Cryosphere concluded:
The AMOC is projected to weaken in the 21st century under all RCPs (very likely), although a collapse is very unlikely (medium confidence). Based on CMIP5 projections, by 2300, an AMOC collapse is about
as likely as not for high emissions scenarios and very unlikely for lower ones (medium confidence).
It has long been my opinion that “very unlikely”, meaning less than 10% in the calibrated IPCC uncertainty jargon, is not at all reassuring for a risk we really should rule out with 99.9 % probability, given the devastating consequences should a collapse occur.
8. But: Standard climate models probably underestimate the risk. There are two reasons for that. They largely ignore Greenland ice loss and the resulting freshwater input to the northern Atlantic which contributes to weakening the AMOC. And their AMOC is likely too stable. There is a diagnostic for AMOC stability, namely the overturning freshwater transport, which I introduced in a paper in 1996 based on Stommel’s 1961 model. Basically, if the AMOC exports freshwater out of the Atlantic, then an AMOC weakening would lead to a fresher (less salty) Atlantic, which would weaken the AMOC further. Data suggest that the real AMOC exports freshwater, in most models it imports freshwater. This is still the case and was also discussed at the IUGG conference.
Here a quote from Liu et al. 2014, which nicely sums up the problem and gives some references:
Using oceanic freshwater transport associated with the overturning circulation as an indicator of the AMOC bistability (Rahmstorf 1996), analyses of present-day observations also indicate a bistable AMOC (Weijer et al. 1999; Huisman et al. 2010; Hawkins et al. 2011a,b; Bryden et al. 2011; Garzoli et al. 2012). These observational studies suggest a potentially bistable AMOC in the real world. In contrast, sensitivity experiments in CGCMs tend to show a monostable AMOC (Stouffer et al. 2006), indicating a model bias toward a monostable AMOC. This monostable bias of the AMOC in CGCMs, as first pointed out by Weber et al. (2007) and later confirmed by Drijfhout et al. (2011), could be related to a bias in the northward freshwater transport in the South Atlantic by the meridional overturning circulation.
9. Standard climate models get the observed ‘cold blob’, but only later. Here is some graphs from the current IPCC report, AR6.
10. There are possible Early Warning Signals (EWS). New methods from nonlinear dynamics search for those warning signals when approaching tipping points in observational data, from cosmology to quantum systems. They use the critical slowing down, increasing variance or increasing autocorrelation in the variability of the system. There is the paper by my PIK colleague Niklas Boers (2021), which used 8 different data series (Figure 6) and concluded there is “strong evidence that the AMOC is indeed approaching a critical, bifurcation-induced transition.”
Another study, this time using 312 paleoclimatic proxy data series going back a millennium, is Michel et al. 2022. They argue to have found a “robust estimate, as it is based on sufficiently long observations, that the Atlantic Multidecadal Variability may now be approaching a tipping point after which the Atlantic current system might undergo a critical transition.”
And today (update!) a third comparable study by Danish colleagues has been published, Ditlevsen & Ditlevsen 2023, which expects the tipping point already around 2050, with a 95% uncertainty range for the years 2025-2095. Individual studies always have weaknesses and limitations, but when several studies with different data and methods point to a tipping point that is already quite close, I think this risk should be taken very seriously.
Conclusion
Timing of the critical AMOC transition is still highly uncertain, but increasingly the evidence points to the risk being far greater than 10 % during this century – even rather worrying for the next few decades. The conservative IPCC estimate, based on climate models which are too stable and don’t get the full freshwater forcing, is in my view outdated now. I side with the recent Climate Tipping Points report by the OECD, which advised:
Yet, the current scientific evidence unequivocally supports unprecedented, urgent and ambitious climate action to tackle the risks of climate system tipping points.
If you like to know more about this topic, you can either watch my short talk from the Exeter Tipping Points conference last autumn (where also Peter Ditlevsen first presented the study which was just published), or the longer video of my EPA Climate Lecture in Dublin Mansion House last April.
It’s a sniper’s bullet pointed right at our heads. It might be 1,000 yards away, but, if we don’t move, it’s going to kill us.
Well, as you can see clearly a shutdown of the AMOC will save our asses here in europe with lovely colder temps. But the question is what are the effects in other regions of the planet.
Lovely colder temperatures may not be great for growing crops, you do eat food, right?
clearly food is lacking nutrition
Shutting down the AOMC would be a great way to create a worldwide famine. Such a large change in the circulation would induce both oceanic and atmospheric changes through teleconnections, changing the climate everywhere in ways that might not be very predictable. The problem for food is that everyone grows crops that are best adapted to the normal weather in their particular area. If that normal changes abruptly, farmers don’t know what to grow, and their accustomed crop is likely to yield poorly or fail entirely. It also affects the seed supply. Even if your climate has shifted so that you are now better off growing soybeans than wheat, it won’t help you if you can’t get the equipment or seeds for your new crop.
This has happened to me on a very local scale. When I first took on an allotment in 2013, I managed to get a reasonable variety of crops from it (potatoes, broccoli, leafy greens, beans, leeks) for a few years. When 2018 arrived we had a ridiculous locked in weather pattern in spring and early summer which resulted in hardly any rain for many weeks. It was difficult to keep my crops alive and some of them failed. Ever since, I have been subject to locked in weather patterns bringing either weeks of bone dry or soaking wet weather and I can no longer get much out of the allotment despite the amount of work I put in. This year is the last straw, planting out three beds of brassicas after a soaking wet spring followed by five weeks of zero rain followed by a wet July. The transplanted seedlings failed to establish and after a week on holiday got swamped with weeds and wrecked by molluscs. All I have to show for my efforts so far is French beans and potatoes. I think it is time I threw in the towel and leave the food production to those who know what they are doing. Gardening never used to be this hard in the UK.
Europe will turn glacial. Those cold temps won’t be so lovely, unless you live in an igloo.
And the quality of the debate below shows how firmly we are routed to the spot.
Can commenters please not use metaphors that threaten the reader with gun violence? Thank you.
The Earth’s rotation and the Coriolis effect also play a large part in the AMOC mechanism. It’s non-intuitive but in the inertial frame the flow would eventually stop, however enough other gradients exists that it sustains itself. The other aspect is tides — if lunar forces are enough to modify the earth’s rotation rate, verified by measurements of length-of-day, then these torqueing forces will also cyclically impact the flow. Perhaps this is better illustrated by the AMO as contrasted to the AMOC.
Interesting math of flow and waves here, where they explain how certain Kelvin waves follow shorelines and interfaces only in a specific direction, again according to Coriolis:
https://www.quantamagazine.org/how-quantum-physics-describes-earths-weather-patterns-20230718/#comments
This is from a few days ago, but I have been following that work for several years now and am only surprised how little attention it’s getting. Could be that the math of quantum physics is a little too heavy. I’ve been applying it for modeling various climate indices: https://geoenergymath.com/2023/07/17/the-big-10-climate-indices/
Re: Paul Pukite 24 JUL says
On a technical matter – haven’t you just … stormed out of here?
Paul Pukite 11 JUL:
“What happened to my response to Piotr? Where I paid tribute to 2 late collaborators of mine? Perhaps it’s not worth my time here, or as they used to say on the blogs GBCW. Find me on Threads.net/PaulPukite ”
W not C anymore?
I suppose you don’t have anything technical to contribute, eh Piotr? Just the typical gatekeeper duties?
Paul Pukite Jul 25 Suppose you don’t have anything technical to contribute, eh Piotr?
To your current recurring complaining why the other people are not into things that interest you (Paul P., Jul 24: “ surprised how little attention it’s getting“) I have already contributed my suggestion: here.
As for your Jul 11 dramatic exit from this site (“GBCW” – Good Bye Cruel World, right?) – I couldn’t comment then – on an off-chance that had meant what you said. With your return, and behaving as if nothing happened, we know that you hadn’t. Still, I couldn’t stop the chuckle seeing how little time it took you to do the 180.
Just the typical gatekeeper duties?
Nah, I ain’t no gatekeeper: I don’t decide who can post here and who can’t.
My “duties” are to learn new things about the subject (climate change), test
my views against those of others, and/or to learn something about myself or others. I feel I have learned something about you, Paul… And if you let your guard down for a moment – you could too.
Do you have anything of any value to add Piotr? You apparently don’t understand how science works since you naively point out somebody doing “research for the sake of research”. In fact that’s how fundamental understanding is achieved — no one is going to understand how an El Nino is going to be strengthened with climate change unless the foundational mechanisms of El Nino are understood in the first place. That’s how it’s always been in EVERY scientific discipline. Too bad your aperture is so small.
BTW, everyone should know that GBCW is a sarcastic joke meme, especially those of us that have been blogging and on DailyKos since the early days, circa 2004.
Paul Pukite Jul 27: Do you have anything of any value to add Piotr?
Since I am replying to your posts, it depends on what I have to work with. ;-):
See here – My first reply was to your Good Bye Cruel World post
not exactly scientifically Earth-shattering material. Despite that, I still managed to learn a few lessons:
– don’t leave slamming the door behind you, unless you are really, really, certain that won’t be crawling back 2 weeks later. Poor form.
– if you do – at least have the class to admit that you were wrong. A bit of distance to oneself goes a long way: “You may be right, I really didn’t think it through”, would have closed the case.
That these lessons are of no value to you surprises me not – based on our previous encounters, you seem a humourless, insecure, man, unable to admit, much less learn from, own mistakes.
My second reply was a repeat of our earlier discussions, you know:
– you’d express bitter surprise that the area of your interests, NATURAL oscillations, is not more appreciated and more intensely researched.
– I’d point that climate CHANGE studies, predicting effects of anthropogenic climate CHANGE, are incomparably more urgent societally – because they provide important and ACTIONABLE information.
– your work with OSCILLATIONS – hence no trend, plus these are NATURAL, so there is little if any actionable information from that research.
To me, the above justifies the large priority, in the resources and research effort, between the climate change research vs. research on the oscillations around the mean.
– To which you’d lecture me on not understanding how science works, and how better predicting of the OSCILLATIONS around the mean is AS important to humanity as prediction of the (AGW) TREND. or quantifying the effects of alternative emission scenarios.
Since you are unable/unwilling to accept the arguments that question your dogma – I can see why would you claim these arguments have “nothing of any value to add“.
Paul Pukite Jul27: no one is going to understand how an El Nino is going to be strengthened with climate change unless the foundational mechanisms of El Nino are understood in the first place
1. It’s an OSCILLATION – so during each cycle its “down” part …CANCELS entirely or at least, mostly, the “up” part. The noise around the trend does not alter the trend.
2. The only effect on the trend would be if the “up” part grew over time more than the “down” part (=>net warming), or vice versa (=>net cooling)
3. The net values in p.2, if ANY, would be small and/or negligible:
– ENSO is a small compared to AGW over 30, 50, 100 yrs.
AND we re talking not even about the max-min of ENSO, but only a small fraction of it – the difference between the increase in the “up” part over the increase in the “down” part.
4. Most important – we CAN’T do anything about ENSO, we can do A LOT about AGW.
That’s why the global climate CHANGE research is the MAIN priority in climate science, and deserves to be such.
Paul P.: “BTW, everyone should know that GBCW is a sarcastic joke meme”
So what – you announced, unsarcastically, that RC is not worth your time, you invited, unsarcastically, people to follow you to your webpage, and when nobody or very few did – you returned, tail between legs, to RC.
Does “ GBCW [being] a sarcastic joke meme” change any of that?
Paul P: especially those of us that have been blogging and on DailyKos since the early days, circa 2004
So what? The older the joke, the funnier it gets?
Contrary to Piotr’s claims, I have nothing to lose by continuing to comment here. The math and physics of geophysical fluid dynamics (GFD) is still in it’s infancy AFAICT. Geoff Vallis, who is an authority on GFD, tweeted recently that the AMOC isn’t collapsing soon and the headlines are overly melodramatic. In contrast, Vallis was quoted that the reduced-dimensional topological wave analysis is a significant advance that will provide a “foundational understanding” of Earth’s fluid systems. A bit of a cross-roads quandry here: which path does climate science want to follow? (1) Horse-race journalism of who can make the most doom-laden predictions, or (2) leave it to the classic peer-reviewed research path where groundbreaking ideas prove their worth methodically and over the course of time.
Paul Pukite: “Contrary to Piotr’s claims, I have nothing to lose by continuing to comment here.”
Must be some other Piotr, because I have claimed no such thing. I merely smirked at how QUICKLY you returned to RC, after saying you bitter goodbyes because RC was not worth your time.
You see, I am a believer in learning from mistakes, my own or of others. You provided the latter. The first lesson I learned from you was:
[P Jul27:] -don’t leave slamming the door behind you, unless you are really, really, certain that won’t be crawling back 2 weeks later. Poor form
See? Nothing about your “losing by continuing to comment here”. You lost however a bit your shine, when you proudly announced DISCONTINUATION of your commenting here because it was not worth your time, and inviting others to follow you to your site, and less than 2 weeks later …change your mind and returned to RC as if nothing happened.
Hence the second lesson:
– if you do – at least have the class to admit that you were wrong. A bit of distance to oneself goes a long way: “You may be right, I really didn’t think it through”, would have closed the case.
Let me continue then (since I don’t care what you think Piotr). The topological wave analysis that Geoff Vallis said provided a “foundational understanding” of Earth’s fluid systems, is something I first cited in 2018, in Mathematical Geoenergy, where in part inspired by this work I outlined a simplifying ansatz on how to model climate behaviors such as ENSO and AMO. The AMO model in particular is an eye-opener because it works on many time scales, from the rapid fluctuations that operate year-to-year to the multidecadal variation that gives AMO it’s name. This aspect of the Atlantic Ocean dynamics must first be understood before the AMOC is speculated on, since the variations in AMO can obscure what AMOC is doing.
https://user-images.githubusercontent.com/2855758/255345824-05e54dbf-3ff2-49db-8f64-3782143ffd6e.png
The ansatz in the book is straightforward but I have since added a first-order intuitive explanation that can take one most of the way there in a cookbook style. My confidence is high on this approach, in contrast to the room-temperature superconducting findings recently announced, because there is no trickery or magic incantations involved — anybody can duplicate the math model by following the cookbook recipe.
Paul Pukite: “Let me continue then (since I don’t care what you think Piotr).
Lady doth protest too much. Out of your 7 posts in this thread, 5 were direct at me or mentioned me in your posts to others. And in the July UV thread – the last thing that pushed you over the edge and made you quit RC, (PP: “ Perhaps it’s not worth my time here, or as they used to say on the blogs GBCW“) was …
“ What happened to my response to Piotr?…
Or, since you like your “ sarcastic joke memes” ” how about this:
(continued) Fluid flows tend toward stratification and staircases if the energetics are favorable. That’s an assumption that I make in my model of an annual (monomictic) metastable transition modulated by tidal forcing. The staircase “risers” that form show a slight linear decay toward a long term mean value. This is crucial, as the primitive equations of fluid dynamics — in this case Laplace’s Tidal Equations (LTE) — are straightforwardly solvable in these linear regions, since the 2nd-order divergence terms go to zero (i.e. 2nd time-derivative of a linear rise = zero). I hinted earlier at a first-order intuitive explanation, and that’s it. What happens to satisfy the LTE derivatives during the non-linear step transitions is a “don’t care” for now, as the model effectively cross-validates all the cyclic fluctuations in AMO, ENSO, etc given the calibrated cyclic tidal forcing. Conventional tides have always demonstrated a non-linear character, as evidenced by the Mt, Mq, Msm, etc factors and this is an exaggerated example of a tidal response when operating on a metastable thermocline. Essential idea published in late 2018 by Wiley/AGU and I have been cross-validating the models since.
Paul Pukite, Jul. 24 “if lunar forces are enough to modify the earth’s rotation rate, then these torqueing forces will also cyclically impact the flow.”
“Cyclically“! I.e. of relevance to the climate CHANGE (the main subject of this forum) only, as the NOISE that one has subtract to get a more accurate reading of the TREND.
And unless you postulate that these natural oscillations would change the trends – it remains a research for research sake – a problem that is neither affected by what we, as a species, do, nor does is affect the trends of things we do have an influence on.
In other words, studying the exact mechanisms of the natural oscillations that happened as long as the Moon is around – cannot inform the society on the consequences of our actions or inactions, which is an important part of
raison d’être of the modern science in general, and climatology and oceanography in particular,
Which may explain why most of the people in the field have … different priorities. And why you really shouldn’t be “surprised how little attention it’s getting“.
To borrow from Juliusz Slowacki – “No time to grieve for roses, when the forests are on fire”.
Pjotr
Be aware 0f the sudden catastrophic and “unlinear” happenings in nature and in the physics, in business, in science, and in life,…, that may have quite minoresque microscopic ” causes” by very large, dramatic even overwhelming outcomes.
An el- dorado also for supersticion and conspiration theories.
The moon , even the cat, causing this and that, is not strange and uncommon at all. It may be the truth.
Because, take the moon or take the cat away, and it would definitely not have happened, that is for sure.
Pjotr
I can tell it even more distinct.
Lord rayleigh, who was a great performer and magician in the lab and on the stages, designed an experiment of a laminar flow gas flame that suddenly flaps over into turbulent state….
…..that is obviously another flow mode…
……..and back again…..
……. on tiniest impact signas from several steps away, as if he were a Magician and higher spiritual SHAMAN or Vhichdoctor in CIRCVS.
by saying “….ssssSSSss….” or
by …rissSsle…. by a bunch of keyes in the air.
Beat that first and you will only be above Lord Rayleigh in the grades in science..
It is called “critical phaenomena” that are quite important for minute detection by extreemly high natural amplification with hatural and critical avalanche- effects.. The geiger counter for instance. where a tiny electron causes a spark in the tube and a large bang inn the loudspeaker.
Rayleigh also showed laminar current in water fountains that changed form and modul dramatically and largely by tiniest and invisible impact causes. The musical flames and the musical fountains. For Royal Society performance at the royal festivals.
Another example, the tiny drop that makes the very beacher flow over.. or the tiny bump that makes the fameously large and high loaded waggon tilt over. That travels very smooth and regularly until that special bump that was ignored……..
Also called “tipping points”. “Unlinear…”, ………and…….. “highly irreversible behaviours”.
Be aware of this when you criticize and correct on Paul Pukite (@whut),……
……because he is also working and searching in theese kind of fields. namely in the ENSO.
I took at look at this link. To my knowledge, all fluid phenomena (from hypersonic flow to geophysical fluid dynamics) are well modeled by the Navier-Stokes equations. To show anything new here the authors referenced would have to at least demonstrate a failure of Navier-Stokes to adequately model a natural GFD phenomenon. And even that would only constitute an inadequacy in the NS model The NS equations themselves are of course only a model of an underlying physical reality. Other physical dynamical phenomena governed by other similar systems of partial differential equations may bear qualitative similarity to fluid flow. This says nothing about the actual physics. At best it’s a simple analog which says more about the governing mathematics than the physical phenomenon.
Piotr said:
I have given it serious thought to stay away from earth sciences publications and concentrate on physics or applied physics for the work I am doing. Given the potential breakthroughs other groups are making applying topological analogies from solid-state physics (see https://www.quantamagazine.org/how-quantum-physics-describes-earths-weather-patterns-20230718/) it may be the only way to give the discipline a kick-in-the-pants. The strange behavioral patterns of fluid dynamics are only beginning to be revealed and from what I am finding, the math is not that difficult, only changing our perceptions and expectations remains challenging. Physics publications have no problems with looking at new paradigms, in contrast to the staid world of the geosciences where progress historically moves at a glacial pace.
Jonathan David was implying that there must be a failure of Navier-Stokes for this to happen. I don’t think so as N-S can accommodate various behaviors due to its nonlinear nature. More behaviors in fact that anyone can possibly dream up.
@ Paul Pukite
Here, you tell a lot of things that is hardly integrated, hardly keeps mtogether and hardely systematic.
I chose the keyeword “Kelvin- wave” to try and look into it, and found back into model theoretical conscepts that are hardly appliciable to waves and vibrations oscillation in molecular matter recardless ofv scale and size from the atoms up to tyhe galaxies.Kelvin waves are as illusoric as the absolute cylinder, the absolute cycle, the absoluteb straight line and the absolute parabel in the so0lar system.
Kelvin waves and “plane waves” are a mostb blocking and misleadsing idea in wind instrument acoustrics and radio tecyhnology and practical navigation.
Rather set onn the oscilloscope that shows anyting bgut Kelvin waves, ande rather set on the chladni experiment with violin bow or with electromagnetic vibrator. Take that rather for reality, and take4 a further looki at https://no.wikipedia.org/wiki/urnesstil
@ Paul Pukite
Here, you tell a lot of things that is hardly integrated, hardly keeps together and is hardly systematic.
I tried the keyeword “Kelvin- wave” to try and look into it, and found back into model theoretical conscepts that are hardly appliciable to waves and vibrations oscillation in molecular matter recardless of scale and size, from atoms and molecules via the 7 seas, up to the galaxies.
“Kelvin waves” were we say the much more precise “pure sinus”, ……are as illusoric as the absolute cylinder, the absolute cycle, the absolute straight line and the absolute parabel in the universe. which are all things that simply do not exist. Only in the qvasi- religious delusions of people.
Kelvin waves and “plane waves” are the most blocking and misleading model conscept- ideas in musical wind instrument acoustrics, radio technology, meteorology, and practical navigation / engineering. .
Rather set on the oscilloscope that shows anyting but Kelvin waves, and rather set on the chladni experiment with violin bow or with electromagnetic vibrator. Take that rather for reality, and take a further looki into https://no.wikipedia.org/wiki/urnesstil
which is an early human model conscept on UNESCO- list rather closer to physical, meteorological, scientific, and climatic, oceanographic reality.
And a bit Irish also.
It is not “kelvin waves”.
It is dispersion, interacting with real climate and real, quite common matter, the understood, operational way They could not disqualify that early understanding from before, so they put it for display until doomesday on the northside of the Temple.
It is typical timeless wisdom.
Try rather and get aquainted to timeless wisdom on UNESCO- level, and you may dissolve even the pacific not to speak of the atlantic ocean.
I could crack and de- chiffer most impossible understanding and engineering problems of plain and clear historical wind music by simply taking the Urnes- dragons as shown on oscilloscope, for real and serious.
People have understood it before. whereas the kelvinwave modellings will only lead you into MEDUSA and a thornehenge of quantum mechanic statistics & speculations on the computer.
re Piotr: Actually, I tend to side with Paul Pukrite on this point: it is difficult to understand a change in a system if you don’t understand the system. Regarding ENSO, from a purely niave perspective, one could imagine the shape, and size, and frequency, and mean of the fluctuation could vary with climate – on that last point, I remember some time ago there being talk of a permanent El Nino state being a possibility (not sure where the science is on that).
And if work done one phenomena is applicable to another simply due to the same mathematical structure or class thereof, so be it. It’s not all that surprising.
Although: from https://www.quantamagazine.org/how-quantum-physics-describes-earths-weather-patterns-20230718/#comments : “ The equatorial waves existed, just as predicted. But Matsuno’s equations didn’t explain everything about the waves. And they weren’t enough of an explanation for everyone; just because you can solve an equation doesn’t mean you understand it. “Are you really satisfied with the ‘why’?” Biello said.” – well, how does using math from quantum-mechanics make it any more grok-able? ( https://en.wikipedia.org/wiki/Grok ) … I understand/agree with Biello’s point – I have considered how lines of vortices will create vorticity anomalies that strengthen or weaken each other to gain a qualitative understanding of Rossy (vorticity) wave group velocity. I expect going over the physics as if one is engineering the wave (rather than solving general equations to show they can exist) would allow a similar level of understanding for Kelvin waves.
Also from the same source: “These scientists wanted a more intuitive, physical explanation for the waves’ existence; they wanted to understand the phenomenon in terms of basic principles and to answer questions like: What’s so special about the equator that permits a Kelvin wave to circulate there? And “why the heck does it always travel east?” said Joseph Biello, an applied mathematician at the University of California, Davis.” – well, I could have expained it to them.
Kelvin waves and inertio-gravity waves are gravity waves modified by the coriolis effect.
Basic gravity wave: a wave pattern in mass (ie. height of a density discontinuity surface of a fluid layer) propagates; it creates a pressure gradient force (PGF), which accelerates the fluid, which creates a velocity oscillation, which creates regions of divergence and convergence, which change the mass distribution, thus propagating the wave. Shallow water version (simplification – ignore the need for motion of the overlying fluid (air) – **not sure offhand how this would affect the rest of these points**): phase speed is independent of wavelength (deeper water: I infer due to the vertical accelerations, the PGF acceleration decays with depth so the wave acts like it is not using the full depth of fluid; dispersion due to phase speed depending on wavelength, correct?).
Coriolis effect turns the velocity around – this should tend to increase the frequency, more so when the frequency is low because the effects of planetary rotation will be felt more on time scales that are not much shorter than the period of rotation. When the frequency approaches the Coriolis parameter f, you approach inertial oscillation, which would occur with zero PGF and therefore corresponds to infinite wavelength. So…(I may come back to this another time).
Anyway, with Kelvin waves there is a boundary that gets in the way of transverse motion caused by coriolis effect, so a PGF balances the coriolis force instead; the setup which achieves this for propagation along a straight edge (not sure about curves) is an exponential decay of wave amplitude toward the left in the Northern Hemisphere of wave propagation (decay length scale proportional to 1/f). A boundary must then exist to the right side (N.Hem.). The equator works qualitatively as such a boundary because f is 0 there, 0 to the North (it is proportional to the sine of latitude). So Kelvin waves can propagate eastward along the equator (until they reach a coastline).
Things get a bit more complicated with multiple fluid layers (internal waves) or continuously stratified fluids (generally, the atmosphere). As I recall, vertically-propagating gravity waves in a continuously strat. fluid (important in driving the QBO) are transverse waves (right?), whereas they are (absent Coriolis effect) longitudinal waves in the shallow water case. If I remember correctly, group velocity is up when phase planes are tilted so that phase propagation appears downward (relative to fluid motion) – this can be reasoned through the same way as one can reason through Rossby wave behavior, because in this situation, gravity waves have vorticity – in this case, the ‘restoring force’ is not a PV (potential vorticity) gradient but the stratification – buoyancy anomalies are produced by vertical motion, and their juxtapostion generates and destroys vorticity of motion in the vertical plane. The result is qualitatively similar to a Rossby wave with respect to vertical group velocity. Note that now you can understand how vertical variations in wind shear would affect gravity wave propagation.
I want to thank Paul Pukrite for that link; I now have some sense of what a topological insulator is.
But as for gravitational tidal influences (besides butterfly effect), I’m… well, I don’t know about ENSO, but I’m very doubtful about it playing a significant role in QBO. Note that LOD (length of day) variations can be due to internally (as in within the Earth’s inner core + outer core + mantle + crust + ocean + atmosphere ) driven rearrangements of angular momentum.
PS to any doubters of the reality of gravity waves, they have been well documented – see Wilson et al., “Surfin’ U.S.A.”
patrick: Aug 4: “Actually, I tend to side with Paul Pukrite on this point: it is difficult to understand a change in a system if you don’t understand the system.”
Only if the oscillations affect _significantly_ the slope of the global warming trend
Paul Pukite has been bitterly perplexed at why most people are interested in TREND (global warming), instead of his hobby horse of the tidally controlled OSCILLATIONS. To which I gave (July 27) 4 reasons, I don’t see a convincing counter to ANY of the 4 in Mr. Pukite’s or your answer:
me Jul. 27: ” 1. It’s an OSCILLATION – so during each cycle its “down” part …CANCELS entirely or at least, mostly, the “up” part. The noise around the trend does not alter the trend.”
you: “one could imagine the shape, and size, and frequency, and mean of the fluctuation could vary with climate”
We are discussing a reverse problem – changing the shape of the fluctuations affecting the climate trend. And I have already addressed that contingency:
me, Jul. 27: “2.The only effect on the trend would be if the “up” part grew over time more than the “down” part (=>net warming), or vice versa (=>net cooling)”
but here came my follow-up argument why that is not likely to be significant compared to anthropogenic forcing of the climatological trend:
me, Jul. 27: “3.The net values in p.2, if ANY, would be small and/or negligible: – ENSO is a small compared to AGW over 30, 50, 100 yrs AND we re talking not even about the max-min of ENSO, but only a small fraction of it – the difference between the increase in the “up” part over the increase in the “down” part.
Even if we took the Low probability, maximum effect scenario- that in this century the world got stuck in the permanent El Nino – then if we assume that El Nino adds say
01.C- 0.2C to global temp. anomaly, that’s still NEGLIGIBLE compared to the temp rise anthropogenic global warming over the same period.
me, Jul. 27:”4. Most important – we CAN’T do anything about ENSO, we can do A LOT about AGW.
And that’s why the global climate CHANGE research is the MAIN priority in climate science, and deserves to be such. Maybe I missed something in your post, but I haven’t noticed anything that challenged my 4 points.
If I did – to my Perhaps because you seem to be again (see the water vapour discussions)
discussing a tree while missing the forest: you go into a few pages of very narrow technical arguments with, well, …somebody, while failing to address my main argument – which you could have done by showing, even SEMI-QUANTITATIVELY, how the changes in short-terms oscillation that “you could imagine” … could actually add to anything – i.e. could CHANGE SIGNIFICANTLY the long term climatic TREND.]
And if your maximum effect scenario – permanent El Nino – is not likely to do the trick (see above) then even more so in the much more realistic NOT-extreme case scenarioes.
Patrick said:
“Proof”: At altitudes directly above the QBO, the SAO is observed — this is an EXACT semi-annual oscillation of equatorial stratospheric winds. Can only be due to a tidal cycle, although it could be a thermal tide as density of these layers are less, but since the density increases for lower altitudes, gravitational tidal forces are strengthened. The statistical significance of this effect must be considered as the QBO cycle again matches EXACTLY as predicted for lunar cycles. Someone is dropping the ball in not addressing this (via cross-validation, number grinding, etc) in atmospheric science circles.
I’m now constantly reminded of the recent LK-99 superconducting material finding report. That demonstrates the proper way that science proceeds — once the details were known, other research teams tried or are trying to replicate the experiments. LK-99 may well be a topological material as well since the initial guess is that it is a 1D superconductor with the magnetic vortices perhaps pinned along grain boundary edges. Yet, as many have pointed out, even if the original findings are wrong, more eyeballs on the idea may lead to other discoveries since there is a wide-spread understanding that something novel is occurring.
If I remember correctly, group velocity is up when phase planes are tilted so that phase propagation appears downward (relative to fluid motion) – this can be reasoned through the same way as one can reason through Rossby wave behavior, because in this situation, gravity waves have vorticity […] The result is qualitatively similar to a Rossby wave with respect to vertical group velocity.
– Actually this may be for the along-phase line/plane component of group velocity, (orthogonal to the along-wave vector component; both having projections in the vertical direction)…
re Piotr – yes, the 1st paragraph was re you; next was a general statement; most of the rest was re Paul Pukite and re https://www.quantamagazine.org/how-quantum-physics-describes-earths-weather-patterns-20230718/#comments , and the last paragraph was re Carbomontanus, who seemed to doubt the reality of these waves.
re Paul Pukite –
I’m not expressing any doubt regarding the thermally-driven tides (which I know are called ‘tides’ but I tend not to think of them as such).
QBO: Where’s the momentum coming from? If LOD (length of day) varied by ~1 hour every ~2-3 years, I could see this driving 50 m/s variations in velocity at low lats, but that’s not happening. Maybe… well, we could figure some wave-mean interaction concentrating the momentum in that region from a more dispersed overall change in atmospheric relative angular momentum… but how much does LOD change in 2 years?
Scientists have identified a mechanism for the QBO and I get the sense that they have evidence/obs to back it up.
https://www.realclimate.org/index.php/archives/2023/05/cmip6-not-so-sudden-stratospheric-cooling/#comment-811812
https://www.realclimate.org/index.php/archives/2023/05/cmip6-not-so-sudden-stratospheric-cooling/#comment-811942
How hard did you have to look for the lunar cycle correlation? Remember, the harder you have to look for a correlation, the more likely you are to find a coincidence. (How precise is the match…)
Patrick said:
It took me a couple of days back in June 2014. I documented all this because I use my blog as a notebook, so my initial findings are posted here: https://geoenergymath.com/2014/06/17/the-qbom/
I did initially benefit from using a machine-learning utility called Eureqa, but that quickly turned into proprietary software.
Now It’s been nearly 10 years later and the exact same correlation exists, so that blog post was an official documented prediction and the current data provides an experimental validation.
What you seem to be missing is that these momentum changes are happening quickly because the tidal forces are changing over the span of days to weeks, not years. The reason that the triggering only takes place at longer time frames is because the annual swings provide the interval at which QBO reversals are most sensitive, i.e. metastable. This leads to the math of sideband frequencies and signal aliasing. As you can read in the blog post, I was able to reason about the aliasing arithmetic quite quickly, as that kind of stuff was second nature to me.
@ Patrick o twentyseven
“…Re carbomontanus whom seemed to doubt the reality of those waves…”
NO!
I am throwing doubt on patrick o twentysevens “take” on them for several reasons.
It is not adult, qualified, scientific, and professional to go in with a Porsche in combination with a broad “combine harvester” to find out and to sell that, , with less experience and understanding of what you are going into.
Could you elaborate/speculate a little on the likely consequences of AMOC instability/shutdown. I assume less efficient heat transfer from equator toward the poles means more rapid heat build-up toward the equator and mid-latitudes. What about the atmospheric jet stream? What happens to the Greenland ice sheet?
A good argument Dr. Doug, I have not seen it before.
They dream of AMOC breakdown as the opposite rather seems to happen.
@Doug,
while my interest pertains moreso to atmospheric heat transport and surface budgets, I realize it is necessary to conceptualize it in relation to the Earth system process.
What do you think of a supposed compensating mechanism between oceanic heat transport (dominated by sensible heat), and that of atmosphere which is dominated by latent heating and associated radiative cooling?
https://www.nature.com/articles/srep16661
Assuming a poleward atmospheric transport of heat depends largely on gradients of surface evaporation – I suppose a hypothetical heat build up towards equator in ocean could result in a compensating increase of equator to pole surface evaporative gradient.
hotter equatorial hots in the seas must initiate more atmospheric power. no ?
While atmospheric magnitude of heat transport exceeds that of ocean by a factor of 5x, the ocean transport of heat is rather limited to deep tropics.
Conversely, what of a hypothetical forcing to atmospheric heat transport (more or less)? Do you think ocean strives to compensate such a change?
A very important summary Stefan that needs to be read and studied by a much wider audience than the RealClimate website, and various, traditional publication strands, may reach. The great challenge for science is to dispel the myths and misinformation and educate and raise awarenss in the simplest of ways so that it becomes understandable by all. This is key if there is to be any chance of saving our world. As new insights like this emerge it is essential that they become mainstream knowledge as quicly as possible – IPCC reporting is far too slow.
Would tankers with brackish water from desalination facilities be used to disperse where needed? Probably just a drop in a bucket. But how many drops?
Randy V, “but how many drops?”
It depends on what % of glacial meltwater from Greenland (270 km3) hangs around until the deep water formation season. The rest is advected away and does not affect AMOC directly ( although if picked up by the Gulfstream may be brought back ….).
So in theory you could cancel up to 35km3/yr of the portion of the 270km3/yr of meltwater that hangs around and interferes with AMOC.
But then there is a small problem of shipping all this brine. across the world. The brine could be up to S=70, so you would need to ship ~ 20km3/yr of brine across the world. For a comparison, all oil tankers move 1.8Km3 of oil/yr.
To make things more interesting these 20km3 of brine would have to moved not over the year, but in a narrow time window (at the time of deep water formation – late winter?). Meaning also that you would need to build on-land storage for most of these 20km3.
And you would have to sprinkle it the 20km3 uniformly over thousands (?) of km2 of waters (if you dump more brine in one place , the plume will sink out, and won’t increase S of the surrounding surface water). So as it is with the geoengineering fixes – they are neither cheap nor easy.
What would be required to restart AMOC if it reaches the threshold? A new ice age, or does something less drastic suffice?
Basically just wait for some centuries, let turbulent diffusion do its job. That will slowly warm up the deep ocean and reduce the water density there, until it becomes less dense than the high-latitude surface waters so that convection can start again. A “drop dead” ocean without any overturning can’t last forever. In theory, an ocean with overturning only from Antarctica but not the northern Atlantic is also possible.
I shall looki at it.
It’s going to be just fine.
Just not for us.
Pardon!
If AMOC ends, how will that influence the Gulf Stream, and is there a possibility that new streams will occur, to level out differences in density?
Given Greenland meltwater discharge is now well-parameterized under the GRACE monitoring period, is it not a relatively simple exercise to integrate this into the generation of models that produce the correct response, but only express it well after its observation, say, in post-2080 scenarios (your Fig. 5 lower panels). The physics are clearly “largely correct” in the models, just lacking one or more positive feedback loops so that the rates of change (observed-model) jive more congruously. To my mind, beyond Greenland meltwater discharge, the effects of sea-ice loss on enhancing heat flux from the ocean surface to air (sensible, latent) is another area where these nasty little feedbacks may lurk. I agree with the author that the community is pressed to get these correct, for an audience much much greater than that of RC.
[Response: Yes. We have already done this (paper in prep), but in our model it does not produce a significant (or detectable) response in the AMOC. This result might be sensitive to the climatological simulation (and any biases it has) and so you’d want this to be looked at in multiple models. – gavin]
Well the problem with that is that inter-annual variability of P-E is an order of magnitude larger then any FW flux anomalies from the Greenland Ice Sheet and they are not well constrained or observed and dominate the FW flux variability in the NA even on decadal timescales. The FW flux anomaly from Greenland has been approximately increasing over the last two decades but it’s still small compared to P-E variability. That could/will change in the future, and probably not so far in the future.
So what is causing the inter-annual variability in P-E (precipitation -evaporation balance of salinity)?
It really is all related to the sensitivity of the ocean’s thermocline to external forcing. The instant that the colder below-thermocline layer approaches the surface, is when the evaporation rate reduces significantly allowing more fresh water to enter the system through precipitation. If I’m not mistaken, isn’t that something of a positive feedback?
There’s a new tipping point abruptly appearing in the northern hemisphere. Soot from the recent forest fires has turned the ice and snow black, greatly increasing it’s melt rate. However, a slower flow rate in Atlantic currents does not necesarily mean cooler temperatures. Real time observations see warmer water farther north. The power driving Atlantic currents is in the solar gain of the southern oceans. Even as it slows, it will continue to warm. Looking more long term, when the ice of the northern hemisphere is gone, will the transfer of heat from the south increase dramatically?
There is no mention of the rapidly decreasing thermal gradient between the polar and tropical regions resulting from the more rapid warming at the polar latitudes in comparison to the tropical latitudes.
How might that impact energy transfer between those latitudes?
Hi Stefan, what is with this study: “The Atlantic Meridional Overturning Circulation at 35°N From Deep Moorings, Floats, and Satellite Altimeter”; Isabela Alexander-Astiz Le Bras, Josh Willis, Ian Fenty; Geophysical Research Letters, vol. 50, 2023; DOI: 10.1029/2022GL101931; online: https://agupubs.onlinelibrary.wiley.com/doi/full/10.1029/2022GL101931 (05.23.2023)
They state: “From 2004 to 2014, the Line W moorings measured a 0.7 Sv yr−1 slowing of the deep western boundary current (DWBC) offshore of Cape Cod. Here, we combine these deep mooring observations with float and satellite altimeter data and find that this DWBC change corresponded to a slowing of the cross-basin Atlantic Meridional Overturning Circulation (AMOC) of about 0.3 Sv yr−1. Our AMOC transport time series corresponds well with the Estimating the Circulation and Climate of the Ocean state estimate, particularly when the Line W mooring data influences our volume closure. We compare our 35°N time series with a similar time series at 41°N as well as the 26°N RAPID AMOC, and find AMOC declines across datasets from 2004 to 2014. However, when we extend our analysis to 2004–2019, there are no significant trends at any latitude. These observations suggest that AMOC decadal variability is meridionally coherent from 26°N to 41°N and that the DWBC may reflect this variability.”
Does there exist critique on it? As it would be for me important to understand the Earth system better if it is now slowing down or not
All the best
Jan
p.s. – this study I also found very interesting which you will not know I guess as they analyzed phytoplankton: Surface currents in the northern Atlantic has doubled their speed during the last 24 years: “Faster Atlantic currents drive poleward expansion of temperate phytoplankton in the Arctic Ocean”; L. Oziel, A. Baudena, M. Ardyna, P. Massicotte, A. Randelhoff, J.-B. Sallée, R. B. Ingvaldsen, E. Devred, M. Babin; Nature Communications, vol. 11, 2020; DOI: 10.1038/s41467-020-15485-5; online: https://www.nature.com/articles/s41467-020-15485-5 (06.06.2023)
Here is a new study thematizing the increased outflow of Arctic water through the East Greenland Current from 2003 to 2019
Here is the Abstract:
Significance The Arctic sea ice retreat has been one of the most dramatic climate changes in recent decades. Nearly 50 y ago it was predicted that a darkening of the Arctic associated with disappearing ice would be a consequence of global warming. Using satellite measurements, this analysis directly quantifies how much the Arctic as viewed from space has darkened in response to the recent sea ice retreat. We find that this decline has caused 6.4 ± 0.9 W/m2 of radiative heating since 1979, considerably larger than expectations from models and recent less direct estimates. Averaged globally, this albedo change is equivalent to 25% of the direct forcing from CO2 during the past 30 y. Abstract The decline of Arctic sea ice has been documented in over 30 y of satellite passive microwave observations. The resulting darkening of the Arctic and its amplification of global warming was hypothesized almost 50 y ago but has yet to be verified with direct observations. This study uses satellite radiation budget measurements along with satellite microwave sea ice data to document the Arctic-wide decrease in planetary albedo and its amplifying effect on the warming. The analysis reveals a striking relationship between planetary albedo and sea ice cover, quantities inferred from two independent satellite instruments. We find that the Arctic planetary albedo has decreased from 0.52 to 0.48 between 1979 and 2011, corresponding to an additional 6.4 ± 0.9 W/m2 of solar energy input into the Arctic Ocean region since 1979. Averaged over the globe, this albedo decrease corresponds to a forcing that is 25% as large as that due to the change in CO2 during this period, considerably larger than expectations from models and other less direct recent estimates. Changes in cloudiness appear to play a negligible role in observed Arctic darkening, thus reducing the possibility of Arctic cloud albedo feedbacks mitigating future Arctic warming.
“Upper ocean warming and sea ice reduction in the East Greenland Current from 2003 to 2019”; Laura de Steur, Hiroshi Sumata, Dmitry V. Divine, Mats A. Granskog, Olga Pavlova; Communications Earth & Environment, vol. 4, 2023; DOI: 10.1038/s43247-023-00913-3; online: https://www.nature.com/articles/s43247-023-00913-3 (07.23.2023)
I really wonder – if more warm water enters the Arctic and more leaves it, while the AMOC would weaken, this could translate in a reconfiguration of the current system in and out of the Arctic Ocean. But if the AMOC is not weakening as the above study in my first post implies other currents are increasing their volume. Just some guesses, but I really would like to hear an expert opinion on these topics as we observe also more warm water reaching Svalbard… From my feeling, a coherent picture emerges, not necessarily including a weakening AMOC but likely an increased warmer water transport in and out of the Arctic (Also through the Bering straight) but with the possibility of a sudden breakdown of the AMOC as freshwater was (maybe also is) increasing in the Beauford gyre, which could be suddenly released into the northern Atlantic…
Here is another recent study, that comes to the conclusion that the AMOC was maybe not weakening as it was 20% stronger during the early 90s due to extreme winter storms that cooled the water and the decline happened when measurements began.
Here ist the Abstract:
Changes in the Atlantic Meridional Overturning Circulation (AMOC) represent a crucial component of Northern Hemisphere climate variability. In modelling studies decadal overturning variability has been attributed to the intensity of deep winter convection in the Labrador Sea. This linkage is challenged by transport observations at sections across the subpolar gyre. Here we report simulations with an eddy-rich ocean model which captures the observed concentration of downwelling in the northeastern Atlantic and the negligible impact of interannual variations in Labrador Sea convection during the last decade. However, the exceptionally cold winters in the Labrador Sea during the first half of the 1990s induced a positive AMOC anomaly of more than 20%, mainly by augmenting the downwelling in the northeastern North Atlantic. The remote effect of excessive Labrador Sea buoyancy forcing is related to rapid spreading of mid-depth density anomalies into the Irminger Sea and their entrainment into the deep boundary current off Greenland.
https://www.nature.com/articles/s41467-023-40323-9
Here what one of the study authors says:
As a result, the model simulations calculated an increase in Atlantic overturning transport of more than 20%, peaking in the late 1990s. The measurements of the circulation in the North Atlantic, which have only been carried out continuously since 2004, would then fall exactly in the decay phase of the simulated transport maximum.
“According to our model results, the observed weakening of the Atlantic circulation during this period can therefore be interpreted, at least in part, as an aftereffect of the extreme Labrador Sea winters of the 1990s,” summarizes Professor Dr. Arne Biastoch, head of the Ocean Dynamics Research Unit at GEOMAR and co-author of the study. However, he clarifies, “Although we cannot yet say whether a longer-term weakening of the overturning is already occurring, all climate models predict a weakening as a result of human-induced climate change as ‘very likely’ for the future.”
https://phys.org/news/2023-08-winter-storms-labrador-sea-gulf.html
Its just another piece that the AMOC was till now maybe not declining, what is backed by more warm water transport into the Arctic Ocean via the Atlantic, (also through the Bering Strait), faster surface currents across the North Atlantic and inside the Arctic Oceans. Or maybe the deeper Parts of the AMOC decline while upper water movements increase – really would like to hear an expert opinion how all this fits with a declining AMOC…
All the best
Jan
Jan Umsonst,
I’m no expert but I see the situation thus:-
The literature you link-to concerns direct measurement of the AMOC strength. Such measurement is not a simple task and the variability of the things being measured is very high. Thus the squiggles in the graphs on the Met Office Atlantic Ocean measurements dashboard.
Note also the GloSea5 reanalysis plots in two of the dashboard graphs. The basic variation in the AMOC appears readily in reanalyses. The reanalyses can be used to identify proxies for AMOC strength to thus allow reconstructions over decades.centuries/millennia. These yield a declining AMOC while in climate models AMOC is strongly predicted to show a big weakening under AGW.
Not all are convinced of the use of such proxies and see the measured evidence even as being “contradictory on the timing of AMOC decline (ie Kilbourne et al 2022) but such a position is apparently a difficult one given all analyses on the subject.
Thx a lot for your insight MA Rodger, as I follow the discussion since many years and it is still full of contradictions – but it is for sure a difficult task measuring these flows with the sparse data you folks have!
But one thing seems certain: more warm water is reaching the central Arctic Ocean, as many studies on sea ice and the central Arctic ocean mention/measured it which not many contradictions on the topic.
And to measure how the warm water blob under the surface o the central Arctic Ocean increases/warms caused likely by the warmer Atlantic water inflow which also comes closer to the surface is much easier than measuring current systems which are much more dynamic in nature by the end of the day. This is another reason why a slowing down warm water transport into the Arctic seems unlikely. But I will continue to monitor the discussion in the end of the day the experts will find the answer and connect all changes into a mechanisitic whole…
“It has long been my opinion that “very unlikely”, meaning less than 10% in the calibrated IPCC uncertainty jargon, is not at all reassuring for a risk we really should rule out with 99.9 % probability, given the devastating consequences should a collapse occur.”
I so wholeheartedly agree with this. We wouldn’t consider a 10% risk so negligible if it applied to most things in life. What sane person would enter a room if they were told there was a 10% risk doing so would release immediately fatal toxic fumes at them even there was a 90% chance it would shower huge amounts of money for them to collect and keep. The fact that as you say that 10% itself is an underestimate makes the situation even more genuinely concerning.
And now today there is this article in The Guardian.
https://www.theguardian.com/environment/2023/jul/25/gulf-stream-could-collapse-as-early-as-2025-study-suggests
Not another Damien Carrington Event?
Cue an Apple= remake of The Day After Tomorrow
Hmm. Did you happen to catch “Extrapolations” on AppleTV.
If so, I’m curious about your take.
Thank you very much for this update!
Is there any new and comprehensive summary of the potential consequences of AMOC decline, similar to Kuhlbrodt et al. 2009 https://link.springer.com/article/10.1007/s10584-009-9561-y ?
I second this question.
Hello all, I don’t know whether replying here enhances the visibility of my question on a comprehensive summary of AMOC decline consequences. This seems to me a more important question than some of the personal battles going on elsewhere in these comments.
Small typo: your Stommel quote should be “fraught” not “frought”.
Which Emission-scenario was used?
This is mind boggling, esoteric information but I’m not sure how it will motivate the masses to do what is necessary to save our planet if it is still possible. I think more time should be spent explaining why we have created the climate crisis we are in and how to save our planet if it is still possible. For example: https://thelastwhy.ca/poems/2017/7/31/climate-breakdown
This will be my only comment. If you want to help,
Regenerative Governance
Circa 2011~12
Ask me about it.
* Decision-making matrix aligned with regenerative principles, characteristics and patterns. Aligns with historically sustainable socio-political structures.
Why aren’t there more climate poems in The Stuffed Owl anthology?
When your confidence interval essentially includes a counterfactual today, how much confidence do you have in your results? I agree it’s hard to be 99.5 percent sure in that situation, although I’d have high confidence you’ve got a hell of a headline for the press to pick up on.
How would the AMOC change correlate with gulf stream changes? Will the azores arquipel become colder? Or Lisbon Portugal?
(Note for site admin – Comment form is displaying in a different language, “Kommentti”)
I had been hoping the “low likelihood” would persists. Not good news then.
Is there a likelihood of a long term oscillation where AMOC shutdown stops and restarts?
In the first couple paragraphs the AMOC is attributed 15 Sverdrup but then it says the Gulf Stream is “only” 90 Sverdrup…am I misreading?
Re: Bill 26 Jul “the AMOC is attributed 15 Sverdrup but then it says the Gulf Stream is “only” 90 Sverdrup…am I misreading?”
As the 90 Sv of Gulf Stream approaches Europe – it splits – most turns south – continuing to a part of the N.Atlantic gyre, but the lesser part turns north (then west, then south )- and part of it, 15Sv. sinks – driving Global Thermohaline circulation/AMOC.
And this explains why the mere 15Sv of AMOC “moves the bulk of the heat into the northern Atlantic so is highly relevant for climate” – the northern branch of Gulf stream carries warm waters north – giving off extra heat into the air, AND when this now cold surface waters is further cooled in winter,
and has same salt added from sea ice formation – it gets dense enough to sink. Sinking removes the “coldness” from air and surface waters, and deposits it at several km of depth – thus no longer affecting climate in Northern Atlantic, and moves in deep ocean southward (“the southward return flow”) until it ultimately deep reemerges at the surface, but in another part of the world and ~ many 100s/ over 1000 yrs later.
Now if the water supplied to the location of deep water formation is fresher (due to Greenland melting) – it doesn’t get dense enough to sink – so it stays at the surface. Meaning the formation of the cold blob – south of Greenland and weakening/shutting down of AMOC – because the water has no way to go.
Dear Piotr,
Thank you very much for this explanation.
Do you know / can you provide an additional explanation what happens with the rest of the Gulf Stream flow that do not sink as the AMOC?
It is my understanding that also this water cannot stay in high latitudes and must somehow return back to the Gulf of Mexico, am I right?
Greetings
Tom
TKalisz Jul.30: “what happens with the rest of the Gulf Stream flow that do not sink as the AMOC?”
If you mean the southern branch – I answered it the previous post: “As the 90 Sv of Gulf Stream approaches Europe – it splits – most turns south – continuing as a part of the N.Atlantic gyre”
If you mean the non-AMOC part of the northern branch – it could continue circulate for a while in north N. Atlantic, or be fed by the Labrador Current back into north-eastern part of Gulf Stream
TK “It is my understanding that also this water cannot stay in high latitudes and must somehow return back to the Gulf of Mexico, am I right?”
There is nothing to tell the high latitude surface water “you must return back to the Gulf of Mexico!”. If AMOC stops, less water would move into high latitudes , but this water would do what today’s non-AMOC water in the North Atlantic/Arctic. does – circulates around or joins the Lab current and joins the north-eastern part of Gulf Stream.
Your “return to the Gulf Mexico” might apply to the AMOC water – the deep water sinking in the N. Atlantic deep water formation zones – but even that not directly, but only many 100s or over 1000 years later – after that deep THC water – surfaces in Indian and Pacific ocean, and is then returned by the surface currents to the general area near your Gulf of Mexico. Check the “Thermohaline circulation” graphs.
As a Chemical Oceanographer that worked with Broecker, though briefly, may I respond to the commenter that proclaimed “This is key if there is to be any chance of saving our world”.
If we are to save this world my I suggest that we know and comply with the first sentence of US law?
It’s the King with no clothes and nobody wants to look at it but it is what will change our world much more quickly than anthropogenic controls.
Delightfully clear explanation and context about AMOC and tipping points. One typo that needs fixing- in point 6 you write: “Stommel wrote: “The system is inherently frought with possibilities for speculation about climatic change.”
Frought is spelled fraught. Maybe Stommel’s typo, not yours!
Hr Rahmstorf
It was not easy this time.
Fear- mongering is occuring and must be rinsed out first before I can make up any plausible hydraulic oceanic understanding for my own opinions.
Then there are contradicting contributions. , One of them mentioned by Jan Umsonst here, that the Plancton transport along the norwegian coast into the Barents sea has speeded up in recent decades. I have seen that also from Bjerknessenteret. .
There we have another and independent , important eyemark also, the eastern ices. The summer seasonal ice situation at Franz Josefs land and especially Severnaya Zemlya that has cleared up radically after 2000, for everyone to look at and to follow.
Severnaya zemlya first came on the worlds maps under Stalin , who borrowed the Graf Zeppelin airship for it. Those islands were not notices by Nordenskijøld, Fr. Nansen, and Roald Amundsen on their exp0editions but were assumed by the russians, who suggested Czar Nicolai IIs land for them. Quite recently one could sail all around them 2 times in the season, and Fr.Josefs land has been icefree all around several times.
The western ices, Amundsens Gjøa- route remains much more clogged, and that is what even I can follow. .
The fameous Dansgaard Oechsler events during the ice ages seem related to sudden and quite enormeous outbursts of glacial freshwater reserves known as “Jøkullhlaup” as icedams of meltwater are suddely breaking.
Where the Plausibe sources are Lake Agazziz, The Hudson Bay, and The Baltic Sea. next to and under the large glaciers.
As there are no such quite enormeous liquid freshwater reserves in the arctic today or maybe a quite large one under central Grønland, I find it some difficult to immagine further Damstgaard Oechser- events in the near fruture., and hope more for the fameous “Maelstrom”, Moskenesstrømmen to prevail.
Hi here I can help – that is actually a quite interesting development that could lead to an abrupt stop/decline of the AMOC – freshwater is accumulating in the Beaufort gyre – here is the Study which sees here a mechanistic possibility for a Dansgaard–Oeschger event if this fresh water would be suddenly released by the Beauford gyre…
“Labrador Sea freshening linked to Beaufort Gyre freshwater release”; https://www.nature.com/articles/s41467-021-21470-3
From an Earth system perspective I would say that it could be that the AMOC is declining making it more vulnerable towards a sudden freshwater release by the Beauford gyre. But I really wonder if the AMOC is really declining in strength as we have besides the study i linked also the observation that high up at Svalbard more warm water is flowing in…
“Increased ocean heat transport into the Nordic Seas and Arctic Ocean over the period 1993–2016”; Takamasa Tsubouchi, Kjetil Våge, Bogi Hansen, Karin Margretha H. Larsen, Svein Østerhus, Clare Johnson, Steingrímur Jónsson, Héðinn Valdimarsson; Nature Climate Change, vol. 11, 2021; DOI: 10.1038/s41558-020-00941-3; online: https://www.nature.com/articles/s41558-020-00941-3 (08.15.2022)
But we will see how this discussion will evolve in the future – but the mechanism and development for a sudden reduction/collapse of the AMOC is underway. But also here it is not clear if this will lead to a reduction of warm water entering the Arctic as the deep branch of the AMOC just could get shallower (as nI understand it, warm water has to go to the poles – one way or another – but this I would also like to ask the experts). Also I ask myself if a sudden collapse of the AMOC by a freshwater release would have long lasting effects or if it would only interrupt the AMOC for several years. But all these are just guesses from studies I read. But one thing is sure: it will be another surprise for us…
All the best
Jan
And what is also important to know is that not only the surface currents into the Arctic Ocean from the North Atlantic are speeding up, but also the currents of the Arctic Ocean – e.g. Beauford gyre and neighboring shelf currents. So also in this regard a coherent picture emerges – this was also further strengthened by a study studying why diatoms from the Pacific reach increasingly the North Atlantic – besides water temperatures they found that the water transport from the Pacific to the North Atlantic via the Arctic Ocean speeded up. Sadly I do not find this study anymore ;)
oops the last study i could not find I found it again – I was wrong they do not mention faster currents, only more warm water from the Bering strait entering the Arctic Ocean. https://www.mdpi.com/2076-3263/10/5/173 – but faster currents inside the Arctic Ocean are observed.
Hr. Umsonst
Have you heard of the fameous Berlevågfisk?
They noticed a new species from Berlevåg, an obvious Gadidae, Gadus or Pollacus berlevågensis. But after some years it came out that it is equal to the very fameous and very commercial Alascan pollock, a very good fish. Having swam through the Bering street all the way along the siberian coast.,
They are showing up more and more each year and were not known from before in Berlevåg.
Jan Umsonst 28 Jul. “ I really wonder if the AMOC is really declining in strength as we have besides the study i linked also the observation that high up at Svalbard more warm water is flowing in…”
Jan, =we have discussed this in the context of the Cold Blob (the symptom of reduced AMOC) in January.
In short – Stefan’s opening graph in this thread is a major simplification – there is more than one route to bring the water to the site of AMOC deep water formation:
the Gulf Stream approaching Europe first splits in southern and northern branches, and then the northern branch splits FURTHER into at least two subbranches
– the one, shown in Stephan’s graph, goes North by Norway and Svalbard,
– the other, not shown on his graph – goes ~ straight West toward Iceland/S. Greenland i .e. toward the region of deep water formation site
I argue that it is this Western subbranch that would be most “attracted” by the sinking of water (AMOC), while the North-West subbranch which is taking SO MUCH LONGER route through high Arctic – may be driven to much a larger extent by the non-AMOC forcings.
Hence my conclusion then: “ not only it is possible to have colder water off Greenland, without cooling off Norway, but actually it is something to be expected.
Or even warming there – if the air temperatures off Norway get warmer as a result of global warming, and/or when the ocean at lower latitudes is warming and then the Gulfstream bringing this warmer waters into its [Norway/Svalbard] subbranch.”
Details of my reasoning in in: .
Piotr
That Blueblob southeast of Grønland is , up- welling , not down- sinking.
And it is not beeing cooled there. It is cold deepwater comingt up, that must have been cooled elsewhere and not by meltwater or icy winds from the thawing Grønland glacier..
I wrote that it is rotating clocvice. That was wrong. It is rotating anti- clockvice along with the surface current around it, and seems to disappear, get dissolved into the waters around. It seems to mix rapidly into the warm surface golfstream , then makintg it some cooler on its further way..
It may entail that the southward deepwater current from the polar bassin through the Fram- street has not been cooled enough in the arctics, probably because not enouh seawater has been frozen there in recent years So that deepwater current is too light and blobs up more and more where it should not. .The long snaky deepwater current down to Antarktis has got a leak……
Jan Umsonsts remarks of the Beaufort gyre are alarming. We must think over that. Hr Umsonst is suggesting a potencial Damsgaard Oechster- event in near future by it. How scaring.
we must also be aware that the colours are artificial and meant to tell the change of temperatures in recent time, not the steady mean temperatures.
I believe we can conclude from the picture that the surface water temperatures along the east Grønland coast may be lower than in the blueblob, but different from it , rising rather rapidly as they do for instance in the Barents sea.
Carbo: That Blueblob southeast of Grønland is , up- welling , not down- sinking.
Colder water is denser hence do NOT upwell, but tends to sink. Unless it is freshened enough to remain at the surface and is either advected or stays around south of Greenland registering as as “Cold blob”.
Piotr
be aware of that max density at +4 celsius of freshwater also, a basic +parameter of limnology
That max density creeps downwars as the waters are salted.
In the antarctic ice cristalline figures develop at the bottom of the shallow seas at near -1.5 celsius
As that blueblob is hardly a cold blob cooled from above to sink, and as the golfstream surface water is rather salty due to evaporation further souuth, the blueblob may come from below and be more fresh, coming from a lower temperature.
What is radically cooled and frozen out also to sink seems rather to be happening in the polar bassin where also the main atlantic overurning in the north occurs.
The golfstream crosses the atlantic eastward and much of it turning south via Biscaya Spania and Casablanca and enters the passatbelt and stream again with central gyre in the Saragossa sea. The fameous Azores High.
Then the question what one calls “The overturning” and what one terms “The golfstream”.
Learnings terms and 0pinions of that seem not allways to be stable conscistent.
The Golfstream has not in any case got its main branches and overturnings in the Baffin bay and east of Labrador. But there is a large anticlockvice but rather soft gyre in the north atlantic north of Island east of Grønland and west of Norway, found by Bjerknessenteret.no in Bergen. And a rather major gyre in the central arctic ocean and in the Saragossa sea both turning clockvice in the high pressure areas.
@ Pjotr
( Havent I got this in?)
Freshwater has a max density at +4 celsius wherefore freshwater lakes and pools “overturn” each year 2 times by surface waters passing that tempereature.
in saltwater, that max density comes at lower temperatures as also the freezinjg point sinks.
For ocean deepwater to keep near zero celsius worldwide, which it actually does, it must also be quite salty. due to freshwater having been frozen out from it in the polar winters and that remaining very salty water sinks . That is a major “overurning” thermo- dynamic, thermo- haline effect in the oceans that is driving sea currents.
Another effect is tropical evaporation that also makes seawater saltier and heavier, so that it may pass under cooler, brackish water, =the hypo- limneon effect also in large freshwater lakes and treshold- pools and fjords with cooler brackish water in the top layers.
Carbo: That Blueblob southeast of Grønland is , up- welling , not down- sinking.
Piotr: Colder water is denser hence do NOT upwell, but tends to sink.
Carbo: be aware of that max density at +4 celsius of freshwater also, a basic +parameter of limnology”
Piotr: So, you are claiming that the Cold Blob in North Atlantic -is the “upwelling” of lake waters? ;-)
Hint – the ocean is not “freshwater”. so your” “max density at +4 celsius does not apply. Hence my earlier statement about OCEANS:: Colder water is denser hence do NOT upwell, but tends to sink”
The rest of your stream of consciousness, based on your assumption that the oceans are made of freshwater, is therefore moot. Garbage in, garbage out.
Piotr
Never discuss garbage as long as you are alian to scrapdealers and to garbagology
I never wrote or suggested that the oceans were freshwater
You are lacking elementary pool and fjord practical and scientific limnology about salt, water, ices, temperatures, hypolimneons, and annual overturnings.
I am aquainted to all that and going out from that instead
The density curve of water to temperature showed alian to you. The 3rd or z dimension to that is salt content. That, you have to get aquainted to first.
Question:
Why do the lakes and pools freeze on the top and not from the bottom when Piotr is the teacher and expert on water logics here? and why does also saltwater freese from the top?
Next question: How can freshwater ice freeze directly out of saltwater and what happens to the remaining saltwater then?
Elementary reality first Messieur Potr, Elementary reality taken serious and understood first. Else just political LEGO, surrealisms and denialisms from your side.
My very good advice to you.
Carbo: “ Piotr Never discuss garbage as long as you are alian to scrapdealers and to garbagology”
I know one when I see one, e.g.: Carbo: “ I never wrote or suggested that the oceans were freshwater
WHAT ELSE have you implied, in the discussed exchange, I quote:
1. Carbo: “ That Blueblob southeast of Grønland is , up- welling , not down- sinking.
2. me: “Colder waters [“southeast of Grønland”] are denser hence do NOT upwell, but tend to sink.”
3. Carbo: Piotr, be aware of that max density at +4 celsius of freshwater also, a basic +parameter of limnology
WHY to the discussion of the OCEAN, would you EVER bring up the properties of the … “ freshwater ” AND “a basic +parameter of limnology ” UNLESS you thought that “freshwater” and “limnology” were APPLICABLE to the waters “ southeast of Grønland “?
So much for your current claim:
Carbo: “I never wrote or suggested that the oceans were freshwater“
Genosse Piotr
Never teach facultary physical chemists and empirical acousticians, fishers, saiolors and fresh and especially saltwater swimmers and divers about buoancies and densities, and especially not about salt, water, heat, chill, and temperatures.
My record is 17 meters down and up in the mediterraneans, and 12 meters down and up here in the fjord. Beat that first.
And then youi can perhaps discuss a waterbath thermostat with heatinjg or cooling element and propellars for me.
Thanks a lot for your kind answer and thx for the details, so the warmer waters reaching Svalbard is one branch of the AMOC – this was also what I understood that the AMOC has different routes (main corridors) but I never went into that detail. What is interesting in this regard is, that the cold blob south of Greenland is vanishing since some years – are least it is visible here: https://earth.nullschool.net/#current/ocean/surface/level/overlay=sea_surface_temp_anomaly/orthographic=-25.97,25.89,401
I also read some papers on the discussion on the cold blob – as I understand it there exist three possible theories: Aerosol emissions caused it, a reduction of the AMOC or meltwater from Greenland. But I also think that if this branch of the AMOC is declining, it should be the likeliest cause. What is also interesting – the outflow of the east greenland current has increased significantly the last years – so something is for sure changing – would like to see one day a 3D animation of which currents speed up, warm, cool, slow down, increase/decrease their volume etc. to get a better understanding on the changes of all these currents across the Arctic, as the Arctic will have a huge impact on the whole climate system. Here is the study with the east greenland current transporting more water out of the central Arctic https://www.nature.com/articles/s43247-023-00913-3
@ Jan Umsonst.
What I need to know is the saltiness of that “blueblob”, , its temperatures, and the way it rotates, and how it comes and goes related to summer and winter.
Then I can interprete it hydralically the wayI am aquainted in the chemical grassews and wessels..
And I am lacking a lot of such information here.
One thing seems sure and not mentioned. Only I and J Umsonst have pointed at it
namely the quite remarkable thawing of the eastern ices and dramatic higher temperatures at Svalbard and Severnaya Zemlya that are worlds records over large areas, combined with the higher speed of the northward surface norwegian coast warm stream, and seemingly also higher speed both at bottom and on the top soutwards in the Framj street. That together with the increased beaufort sea gyre.
Seemingly also more freshwater down the Baffin bay where deepwater currents will be inhibited. That entails melting of icebergs north of Canada and Grønland that froze in the east arctic and were blown over to the west arctic..
I look at the western ices. It is very clogged and remains tight in the globalo warmings, much more than the eastern ices.
Water, fishes and plancton coming in from the pacific and passing over to our side should mean that the outflow from the arctic east of Grønland through the fram- street has increased consciederably, ……..
…………and this whole picture seems conscistant
The atlantic seems to overturn faster and fraster not southeast of Grønland but in the arctic ocean that seems to be rather a major functional part of the atlantics.
And more important to global climate understanding and projection than even the ENSO.
Jan Umsonst: “ on the cold blob – as I understand it there exist three possible theories: Aerosol emissions caused it, a reduction of the AMOC or meltwater from Greenland”
Of these 3 – I am not sure how the aerosol emission into the atmosphere could have such a localized effect on seawater temperature. The remaining two are likely part of the same explanation – the increased freshness input from Greenland (and via surface currents other parts of the Arctic), when brought into the area of N.Atl. deep-water formation interferes with this formation, and therefore interferes with the force driving AMOC:
For (current) AMOC to work – the surface water in deep water formation areas in winter has to sink. It sinks only when the surface water gets denser than the water below – and it is denser when it is colder and/or saltier. In winter near Greenland there is not much room to get VERY cold – one your temp. drops to -1.9C, typically sea-ice starts forming – which prevents T from dropping below that, BUT which increases salinity – salt does not like ice – so when you freeze seawater – most of its salt is rejected into the surrounding water – making this water saltier, than it was before the sea-ice started to form. If the denisty of the surface water surrounding the forming sea ice is higher than the density of the water below, the surface water sinks, driving AMOC and removing “coolness” from the surface – as the winter cold is exported into deep ocean.
However for this to work – this surface water has to be cold AND has to have high enough S.
Salinity is high if you start with already relatively salty water thanks to the contribution of the salty waters of the Gulf Stream, and then S increases further by adding salt from the forming seaice.
Now, the global warming may interfere with that: if surface currents bringing in waters freshened by the input of the Greenland and Arctic icemelt – then your _starting_ S is already low, and the less cold winters may mean less sea-ice formation, thus less addition of S to the already lower S staring water.. Which means that winter surface water there does not have enough S => not dense enough to sink.
In the past, when it worked – this winter “coolness” was removed with the sinking cold water into the deep ocean, now it stays at the surface, and is only moved around by the surface currents – in places where it gets concentrated – you get the negative T anomaly compared to the times when the deep water was formed at full rate. Hence on the map of temp. anomalies – you see the Cold Blob.
Very informative!
Hi Piotr,
again thanks for your kind answer – the formation of dense waters and the role of sea ice that sink down I studied, as I want to know all these things and how they work into the details. But I only thought on terms of the cold blob of the cold water from Greenland as one possible reason (but did not think that it could also reduce the sinking of cold salty water by diluting it in regard to the cold blob – so thanks here Piotr). But Ramsdorf explained in a post that the energy would not be enough to form this cold blob anyhow. So I went with Ramsdorf.
This is the study with the aerosols being one reason for the cold blob – but I also doubt it: “”Formation of the North Atlantic Warming Hole by reducing anthropogenic sulphate aerosols”; https://www.nature.com/articles/s41598-022-27315-3”
But what is interesting thou is that the main mass loss of Greenland has now moved to the north of Greenland – before it happened in the south near the cold blob – but I’m not 100% sure here, if you want I take a look at to confirm it. But as the cold blob seems to vanish the last years and if its a long-term trend then this shift could have some meaning for the previous as the melt water of Greenland will play a role – but if the amoc declines in strength likely via the secondary mechanism you explained Piotr.
Also the vanishing cold blob – if this trend persists, could be caused by a further warming of the golf stream as it is heating up fast – the current marine heat wave south of Greenland could be an expression of it.
So we live truly in interesting times…
Jan
Just took a look again on the sulfate study on the warming hole – I guess a small influence, as they just state that the reduction of SOx would increase the CO2 warming signal which is responsible for the AMOC decline if it declines. So all three reasons would point in the same direction. Now I can follow your reasoning Piotr that a warming hole is actually a good proxy for a decline in the AMOC as more colder water stays at the surface as it does not sink down as it is not so salty as you pointed out so nicely. But if the warming hole should now vanish things get interesting again.
On the other hand the sinking of dense waters of the AMOC, happens via “waterfalls” inside the water column (a km in diameter or so as I remember) for example near Svalbard is an area where they exist. So the whole thing is much more complex than just cold dense surface waters sinking down over large areas. So the question would be, what is needed to interrupt these subsurface “waterfalls”. And fresher warmer waters will for sure have an effect as it the opposite drives them. But somehow I have the feeling that a non-linear process with thresholds is involved here that leads to the closure of these waterfalls. I’m really curious what you folks will find out in the future on the changes in the Arctic and how it sums up and what feedbacks are involved.
All the best
Jan
Here is another insight of why I have doubts on the decline of the AMOC – at least as a whole: The inflow of Atlantic water into the Barents Sea has doubled in the last 30 years (Oziel et al., 2016; Oziel et al., 2020)
From this study here:
“Revisiting the footprints of climate change in Arctic marine food webs: An assessment of knowledge gained since 2010”; https://www.frontiersin.org/articles/10.3389/fmars.2023.1096222/full
I think the picture of the AMOC decline will be mixed if it is seperated into its different branches which enter the Arctic Ocean. So I would be really be interested in what exactly is declining and what is maybe even increasing…
Jan Aug.21: “The inflow of Atlantic water into the Barents Sea has doubled in the last 30 years
This does not invalidate a decline in AMOC – IF the extra water brought in the Barents Sea just moves around horizontally, but does not sink – then it does not strengthen the AMOC, at least not directly (indirectly, the saltier Gulf Stream waters could counter the freshening from ice melt).
Jan, Aug.20: “ The sinking of dense waters of the AMOC, happens via “waterfalls” inside the water column (a km in diameter or so as I remember) for example near Svalbard is an area where they exist. ”
It may be so, but the question is whether there is enough of them to make the Svalbard area of important deep-sea water formation – oceanographic texts typically place the MOST of it near the south Greenland – e.g. Irminger Sea in the east, Labrador Sea in the west.
Jan,Aug.20: “ I have the feeling that a non-linear process with thresholds is involved here that leads to the closure of these waterfalls”
Almost certainly are – formation/shutting down of these waterfalls is predicated on the right combination of factors – what’s the preexisting T and S of the surface water , what’s the winter air temperature – to lower this T enough to start making enough sea ice to add enough S to make the water sink. And the wind – which help the cooling from air enter the water column, but also if it spreads this cooling over too large depth – does the mixed-layer water gets dense enough to start the waterfall?
But you would never be able to resolve these local and short-term events in large scale measurements, or model simulations, of AMOC – which in effect look at the “integrated” (over large spatial and temporal scale) results of all this local, probably non-linear, and prone to switching on and off, “waterfalls”.
Jan Aug20: as the cold blob seems to vanish the last years
It does not prove restored AMOC – if the air over Greenland in winter is not as cold as in the reference period – then this would reduce the deepwater formation in winter. Now, normally it would mean that the cold surface waters are not removed into the deep ocean and stay at the surface – hence the Cold Blob. But if warmer than usual air continues into spring, summer and fall
– it would gradually warm this surface water – resulting in “vanishing of the Cold Blob“. Furthermore – wind will make the difference as well – if you have less wind in spring and summer, the warming is applied to a smaller thickness of water and therefore, would indicate “vanishing” of the Cold Blob
which is the surface mixed layer temperature.
In other words – the appearance of the Cold Blob is consistent with weakening of AMOC, but the reverse does not hold – the vanishing of the Cold Blob does not necessarily proves strengthening of AMOC, as the seasonal weather (temperature and wind) may “vanish” the footprint of the weakened AMOC.
Twenty years ago, I was firmly in the “skeptics” camp on anthropogenic global warming. Around 2007 or so, one of the arguments for our side going around was that both the AMOC and PDO were going into, or already were in what they were calling a cooling phase. So of course it was only a matter of time before we started seeing the warming change to cooling, and would those dumb climate scientists have egg on their faces.
It was an ongoing prediction featured of WUWT. They were sure of it. THOSE TWO PHENOMENA were the cause of much of the warming…. That and heat islands.
That was not what happened. If I recall, they did enter a cool phase for a bit, but there was no “global cooling” to be found. The scientists here were often criticized for not acknowledging when you got things wrong, which of course isn’t even true, it’s part of the scientific process. After a few years I started pointing out that WE were wrong. Of course the crowd had already moved on to the next big thing to explain why there was no global warming, and turned on me for having the temerity to ask that we admit when we’re wrong. I started making enemies for asking too many question regarding some of the comments. I got banned from one site for trying to explain that, if the sun was causing Jupiter and Neptune to warm enough to be detected by NASA, a story that was going around at the time, if changes in the sun were causing those two distant planets to increase temperature, our planet, much closer, would fry.
I had finally come to recognize the flaw of their endeavors, and my own flaws in reasoning that allowed me to get pulled into that side of the debate…. Or whatever it is.
I’m tempted to visit WUWT to see what nonsense they’ve written about this new report on the AMOC, but i’m afraid my eyes would roll so far in the back of my head, I would see my own frontal lobes.
Anyway, thank you Gavin and everyone for what you do. I’m planning to write a blog post soon about my journey from one side to the other, and it will include an apology to everyone here for the absolute crap I wrote back then.
Mike Alexander aka Sonicfrog.
Mike,
You are acting like a true scientist in that when new evidence came along that didn’t fit your original hypothesis, you changed your mind. Bravo. I am happy to have your voice on our side. Welcome.
Yes, Mike acted “like a true scientist” and like “a true skeptic” – a true skeptic is first and foremost skeptical toward oneself – their own errors, a priori beliefs, and blindspots.
Not many of those in the climate skeptics community … ;-)
Pjotr
The dammage here is done in US american public school , where being sceptic was to be obedient and consequently deny Darwin.
By having another traditional conscept of scepsis and scepticism on this side of the atlantic, we do easily see the flaw. .
On this side of the atlantic, being a bit sceptic means being in doubt and better look after and check up before you eventually buy it and swallow it or reject it.
Interesting article. I am interested in the dynamical modeling approaching a transition to a zero flow state. When modeled as a dynamical system, the actual transition from a stable constant flow-rate state to a zero flow rate state might be expected to be a little more complicated. That is, when modeled in a state space, each stable state would have a so-called basin of attraction which returns the system to stability under small perturbations. When the perturbations become too large one might expect unstable or chaotic behavior until the system settles into the basin of attraction of the zero flow state. What all this would mean is that the flow would not simply stop but would go through a period of random or oscillatory behavior e.g. slowing down then speeding back up again at unpredictable intervals probably on the time scale of the phenomenon which is years presumably. Is this relevant at all?
“It has long been my opinion that “very unlikely”, meaning less than 10% in the calibrated IPCC uncertainty jargon, is not at all reassuring for a risk we really should rule out with 99.9 % probability, given the devastating consequences should a collapse occur.”
Stefan:
If we treat this as “an interim takeaway” (through COP28 and, say, after conclusion of the AR7 cycle c. 2030) as we await further data, I assume European countries, peoples, and their governments will not begin to take any threats of disruption too seriously until after c. 2030 (although I understand the Irish are committing to a considerable livestock reduction already).
If incoming data subject to future analysis confirm the trends you, et al., have already established for AMOC weakening (and if those data begin to suggest acceleration of the weakening towards eventual collapse), what might anyone be able to say about 1) the timeline for climatic and meteorological disruptions across Europe (will a “West to East” pattern manifest itself at all sequentially with any significant predictive value, or will the outbreaks of disruptions of varying circumstances [drought here, floods there, cooling here, warming there] be intermittent, sporadic, and seemingly opportunistic based on other dynamical factors?)?–and 2) what might Europeans, their nations, and their governments actually be able to do to help forestall any perceived threats of AMOC weakening? As a lead researcher, how do you assess present political receptivity of “climate threat messaging” to date, and do you think public discourse on the matter today bodes well or ill for the political disruptions and challenges sure to be ahead if indeed data over the next six-to-eight years confirm AMOC weakening and/or acceleration of weakening with prospects for eventual collapse?
I assume modeling for the possible outcomes has begun both for each European country and continent-wide . . . right?
Keep up all good work.
Thank you very much for this very informative and timely article Stefan. I very much appreciate your writing style, and your ability to convey complex messages in an accessible way, using language which is simple enough for me to be able to understand it. Many thanks for that.
Following a few tweets and news articles about the latest AMOC insights I had been looking for a place where I can read up on this issue in order to better understand it, and your article has been most helpful.
Going further, if it is not too much trouble would you mind writing a follow-up article which explains the concrete consequences of an AMOC standstill, structured by region of the world? Or could you detail the consequences for a few geographical locations (say Brussels, Seville, Barcelona, Amsterdam…) to give readers an idea of what to expect should the breakdown occur? Thanks again!
Let me add, if Stefan Rayhmstorf also can get it.
That the so- called Norwegian stream up the coast ant into the arctic bassin seems not to have slowed down, but rather to have speedeed up in recent decades……………
Further evidence of this is obvious thawing in the eastern ices, in the Franz Josefs land and Zevernaya zemlya area in the same years. See also propaganda and realities of the fameous russian “northern sea route” and chineese interests in the same, ….. compared to the situation in the western ices.
The Bering street is way to narrow and shallow, as shown more than half a century ago as the USN Nautius entered and went under the north pole ices that way and arrived again in the Fram street. I red in the Readers Digest that they were in thick troubble due to shallow waters with thick icebergs in the Beering street.
So , all that “stream” into the arctic ocean the Norwegian… and the Barents sea way, that obviously thaws by warm atlantic water,…. has to get out somewhere, due to the peremanence of matter and hydro- static forces in the gravitati9onal field.
I repeat….!
For that, there is hardly any other plausible way out than out through the fameous Fram- street and Danish street on deep water. See also the massive ices streaming out east of Grønland that gives evidence of surface freshwater and current direction.
This seems to be the mainstream in and out again from the arctic ocean
Further to be be conscidered is the Scotland Færøerne Island underwater ridge, where broad streams of shallow warm surface atlantic water can pass over as forced and driven also by the antipassat Weasterlies”, but no huge deepwater cold stream in Sverdrups… can pass out again. So that it rather passes out again east of Grønland and west of Island, where it is broad and deep and west of the fameous midatlantic ridge.
This alltogether seems to me to be how the atlandtic mainstreams mainly overturns. And what integrates the arctic ocean physically to be rather only a part of the atlantic ocean.
The “blueblob” southeast of Grøland is rotating clockvice, Its saltness shall have been checked. It is hardly recent freshwater meltwater runoff from the Grønland glacier that clills the oceans there and prooves the rapid melting of the Grønland glacier see also the warmer water near to the Grønland coast. It is hardly chilled from the top by cold winds eiter. It is as much as an upcoming salty coldwater gyre from below that seems to mix very well into the eastgoing golfstream that keeps running for other reasons namely the passat and antipassat winds in the atlantic.
So, alltogether I cannot see the problem plausibly described and understood as long as the Barents sea and eastern ices are thawing rapidly. And the norewegian stream accelerates.
Theese oceanographical details ought to be integrated, not ignored or falsified by any happenings in the north atlantic current and turnover systems.
The main polar wind system is a clockvice north polar high pressure cyclone, that drives the mainstream of ices and surface waters over from the north siberian coasts to the Framstreet and against the north canadian arcipelago and part of it steadily out the Framstreet. This was suggested by Fr. .Nansen and shown by his Fram polar expedition by ice- drifting.. And explains very well in many aspects the frappinly thick and remaining ices rather north of Canada. also entailing more freshwater that is frozen in the east and blown over that way.
Comments?
Stefan, thanks for the great post. I still have some questions maybe you or others on this thread can answer:
1) Based on climate ensemble members which simulate a turning-off of the AMOC, how fast does it happen? (for example, to drop to 50% or 1/3rd of it’s typical flow rate)? 3 years? 3 decades?
2) Do we know the expected range of impacts should the AMOC careen off a cliff? I saw one paper that said it could be good for the Amazon, but nothing else in an admittledly-brief literature search showed much. Of question my question is in the context of a warming (CO2-forced) world, not a pre-industrial one.
Chris O`Dell
I am having other experimental technical and model conscepts of practical hydraulics and acoustics that does not go by statistics and computer simulation in virtual matter, so I may be better answering your question 2.
See the Damsgaard Oechsler events that are very typical and plausibe major catastrophic “Unlinear” avalanches and sloshing events , change of current or oscillation mode in viscous molecular mjatter. “Off a cliff” as you sayit. And if at all, harly in the form of a smooth continuous change from a to b major form.
And it happens rather fast, if at all. It seems that this is also what some specialists are worried about. knowing that such sudden and major events are quite common in life and in Nature, the sudden “breakdown” of things and change into quite another situation..
“Steady state” is often just intermediate where things are mooving and streaming.
That’s interesting. In the framework of bifurcation theory this sounds like a so-called “global bifurcation”. A stable state becomes unstable. But there are no other stable states “local” to the now-unstable state (in some space of parameters). This can result in the appearance of dynamic behavior quite different from the former stable state including seemingly random or chaotic behavior. This behavior persists until the system finds another stable state which may be quite different from the first. I have no idea if this would be relevant to the AMOC.
This happens all the time in lakes, where turnover occurs twice per year (dimictic) or once per year (monomictic), with various factors such as the wind, temperature, precip, ice triggering the exact timing. Stable states separated by rapid transitions. Obviously something similar happens in the oceans, with the additional factor of tidal forces either impacting the triggering or modulating the transition. Either of these scenarios require different math than conventional harmonic tidal analysis, as it creates sidebands in the spectrum. To someone searching for harmonic predictability this may appear random or chaotic, but it’s not.
These appear to be examples of Rayleigh Benard convective instability. Benard convective cells can certainly experience further instabilities leading to turbulent or chaotic flow. This may or not pertain to the AMOC depending on the stratification of fluid layers. The relevant forcing would have to be a thermohaline gradient presumably salt heavy fluid over an lower predominantly fresh water layer. Or a warm lower layer with a cool upper layer. Don’t think the first is likely given the description of the phenomenon.
This is ubiquitous in stratified flows with an inverse energy cascade. As I said, the frequency sidebands formed by the tidal harmonics mixed with an annual forcing impulse have always been overlooked. The best place to start is with the QBO of stratospheric winds, where the sideband of 2.37 years is quite striking and is basically in the description of QBO — quasi-biennial ! Chaos is always overriden by a strong forcing.
@ Jonathan David
Yes, I think you`ve got it before anyone else here. That blueblob looks like a Rayleigh- Benard- cell..
As it is up- welling and not down- sinking and colder than the waters around, it must also be less salty.
I think this is criteria and characteristics that Stefan Rahmstorf should also follow ,
As it gives less coflicts & paradoxes with the rest of the northatlantic system and further methods of research and kinds of knowledge around it..
Paul Pukite (@ whut) , look at that. It is solid figurazione- hydrodynamics, of appliciable Leonardo- quality.
Hi Paul, thanks for your response, very interesting. However, I think we are somewhat talking apples and oranges here. The physical system as described by Dr Rahmstorf appeared to me to be characterized by local instability near a point of equilibrium. Your mention of energy cascades implies very highly developed turbulent flow and quite a different flow regime. Also, it seems to me that the length and time scales relevant to the AMOC problem are quite different from those characterizing tidal flow dynamics. Still, I would be interested in any links you might care to post on how you think this all ties together.
Published by Wiley in 2018 as Mathematical GeoEnergy, with web site https://GeoEnergyMath.com providing more recent analysis and cross-validation as expected with any climatalogical data.
I occasionally read them. writings and comments. Since I am not fluent in English, I sometimes have to go to online translators.
I live in Cuba and that is why I am interested in the future of the Gulf Stream.
I am not very clear on what consequences its slowdown would bring to the climate of the Caribbean. If it will transport less heat from the equator or less from here to the North Atlantic; and its influence on the marine life of that current so dear to Hemingway.
Cuba?
Hurrah. We miss you.
I am in Norway, a washproof viking.
And we have Ceskoslovensko here.
We have also New Zealand here They see it from the other side of the globe.
I must cover the Baltic and the Barents sea.
The Golfstream seems secured forever in Cuba as long as Panama is tight.
The mysterious “blueblob” southeast of Grønland matters more for the discussion of the arctic ocean than for the Mexican golf.
What should we think of this work by He & Clark 2022 https://www.nature.com/articles/s41558-022-01328-2
Specially this “we suggest that until the Holocene Meltwater–AMOC Paradox is resolved, any simulated future AMOC changes from freshwater forcing and associated temperature, precipitation and regional sea-level changes should be viewed with caution”
This paradox is defined as “Having a sustained FW flux of ~0.10–0.18 Sv discharged into the North Atlantic and Arctic oceans from 11.7 to 6.0 ka in association with little or no slowdown of the AMOC and associated cooling of the North Atlantic climate constitutes a fundamental challenge to the paradigm of FW forcing of the AMOC”
[Response: I don’t see the logic of this statement. We have plenty of modeling support for a FW impact on AMOC, and good evidence from the 8.2 kya event that is quantitatively consistent. That it might not be the only thing that matters is well understood, so the counterpoint offered here that there was FW emitted in the deglaciation (where is key of course) and no obvious slowdown would only really be important if we knew how the AMOC was supposed to behave in a deglaciation. Note that most of the modeled slowdowns in the CMIP models for the present and near future are due to temperature changes in any case. – gavin]
Is there a big difference in AMOC response between the low, mid and high-climate sensitivity CMIP6 models…at different warming levels or time windows?
Dear Sirs,
I would like to ask a technical question.
Are among techniques used for investigation of the AMOC (and especially of the critical North Atlantic site) also buoys flowing with these streams?
I imagine that long-term observation of such “pilgrimaging” buoys could unequivocally answer e.g. the question whether the cold water in the “blue blob” ascends or descends…
Even in case that there is in fact no such surprising direction reversal as assumed by Carbomontanus, the movement of buoys could perhaps give an accurate information about speed and acceleration (or slowing down) of the stream, its temperature and salinity, and possible temporal changes thereof…
Was it part of the research presented by prof. Rahmstorf? If so, why is there still a doubt even about the direction of the streaming?
Thank you in advance for an explanation and best regards
Tomáš Kalisz
Kalisz
I have also asked Rahmstorf more directly about this, and he only answered “yes, we know and cooperate with the Bjerknes institute in Bergen, all under control.. we are aware of this.”
But, I have learnt that we also must have a hydrodymnamic understanding of it how and where do the currents come , flow and go.
In so many respects, we have the same “technical” questions in the airplanes, in the complex water or aircooled engines, and not least on the complex electronic cirquits and pritchards. In which directions do the turbines go? Where does it heat and where does it cool?
There has come a swarm of Argo- buoys since 2000 so there really ought to be data enough.
A suggestion from my side along with Karel Capeks theory, is that when so many new aspirand workers on the factory floors where the eart is flat are suddenly getting brand new ” Tools” in their hands that is told to do it much faster and better now,…..
………..then all those new ROBOTs are setting off and driving like mad in a mainstream current before they ever learnt to drive at all.
As driving carefully is extra told them to be obsolete now. .
The brand new method is said to be “scientific” and totally safe and will take over all the thinking and swimming and navigating work now. So you will also have a new and better personality. with that at hand. .You can forget all that about temperatures salts and waters currents and winds, and overturnings,…..the method will secure and deliver all that from now on. .
Dear Carbomontanus,
Thank you very much for your hint to the Argo – program.
I looked shortly on their webpage but could not find out quickly if the buoys can (and also do) collect data regarding forcings that may drive them down or up from their “parking” depth 2000 when they drift from one profiling point to the next one.
Thus, it is still not obvious if the abvailable data enable an unequivocal estinmation where / when ocean currents ascend / descend.
I hope somebody with a deep insight in this program can help and will clarify this interesting (and, as it appears, quite important question) herein on the Real Climate website.
Greetings
T
Kalisz
The Argo- buoys seem minutely regulated like balloons or submarines in regard to depth. By compressed air and depth manometers, that is possible. Depth is artificially regulated, but horisontal moovement and drift is passive.
Then what do they measure? Temperature and salinity definitely because that is so easy. But what more? and that is the premises of what they can possibly tell.
It has been known since ww2 at least that layers of water with rather distinct density difference does reflect and interfere with “asdic” and sonar signals, which is also to be expected, and we can guarantee that a lot of research is also done there for military reasons.
I have red of discovery of large Kelvin Helmholz wave systems in between the warm surface golfstream and cooler deepwater in the atlantic, which is also to be expected in layered and streaming hydraulic systems, giving troubble and possibilities for submarine military navigation.
But you can see and study it for yourself in common clouds, windshares between different layers in the atmosphere and obvious wavy oscillations and viscous current morphology between those layers.
Kalisz
There is one more thing that could be easily measured.
Let us say that they are minutely servo- stabilized at a certain water pressure, that entails depth.
Then with a quite sensitive flowmeter outside, follow wether water streems down or up at their sides. or steady no- vertical flow.
and all this stored and logged for further investigation.
With so expensive sondes, I would have thought of that also.
When they come up again, they they have a radio antenna that can give signals for where they are can be picked up again, restored, and re- used.. .
But there are secrets to it also.
There was a very fameous civil sea surface surveyor satelite where data could be taken down by anyone. Then suddenly its power supply system fell out.
It showed that it also detected surface- wave patterns for where large nuclear submarines were mooving fast underwater..
In Re to
https://www.realclimate.org/index.php/archives/2023/07/what-is-happening-in-the-atlantic-ocean-to-the-amoc/#comment-813775
Dear Carbomontanus,
Many thanks for sharing the idea regarding installation of vertical flow-meters on Argo buoys. Are you aware of a discussion or of a plan in this direction?
I could perhaps imagine an alternative way for recording the forces pulling the buoy upwards or downwards from its set depth along its path with oceanic currents:
If the software in the buoy made a log of corrective impulses that were necessary for increasing or decreasing the buoyancy along the buoy path, such records might perhaps serve at least as a qualitative indication if the current exhibited a clear ascending or descending trend along the buoy path.
Greetings
Tom
Kalisz
Now you were clever again
Simply have an engine- log on that minute depth regulation servo and the vaterlevel in the cylindric airbubble that regulates it buyancy
Not even I was thinking of that. I suggested a propellar flowmeter.
Thank you. carbom..
But the waters of the Gulf are getting hotter every day because apparently its heat stays here and doesn’t travel to your cold sea.
The ocean is unique. The water in which I bathe at 32 degrees in Varadero, Cuba is the same as that of your cold fodor. It would not be prudent to wait another 14 million years for the isthmus of Panama to open to save our corals and your fiodor.
Hr. (Don) Armando
It looks definitely to me that Cuban warmth at the Varadero beach with corresponding reefs are progressivly heating up and thawing the impossible, Stalin russian Severnaya zemlya waters in recent years and in our days….. through the Golfstream. So that the fameous pioneering nuclear Icebreakers of the Lenin- class is getting help from Cuba to keep “the northeren sea route” open.
When shall people understand that there is a traditional relation there?
Cuba is exporting not only sugar, but also warmth to the russians.
But, the golfstream may not be quite fast enough.
Maybe there is too much warmth in the pipeline in our days because it is warming too sudden?
Mister Carbomontanus
When I think of Norway, the ones that come to mind are not its politicians but Thor Heyerdahl, Roald Amundsen and A Descent into Maelström by E. Á. Poe. The beauty of its landscapes that I have seen on Cuban TV, and the description of your beautiful country by a Dutch friend and a relative who lives in Sweden.
Because of my love for nature, particularly geography, the rest is of less interest.
That is why I do not know, nor am I attracted to know who Norway sells its cod or its oil and gas to, which by the way the war has benefited.
Excuse me if I update you that Cuba has been exporting very little sugar for many years.
My greetings and my respects. I know something of history, from the time when the Sumerians and Akkadians civilized Mesopotamia, up to the present, going through a day like today when someone dropped a 4-ton bomb on Hiroshima and left a hundred thousand souls exterminated.
Don Armando
On cuba and sugar & cetera.
A lot of cuban sugar was taken and processed into Bacardi- rhum, white and brown. Bacardi was a spaniol, today it is the worlds greatest spiituosa trademark but re- located on the Bahamas for practical political reasons.
Cuba has become an ” amcar” museum. I did know the chechoslovakians and they found a very cheap bag of chechoslovakian sugar here in Norway, as their sugar at home was terribly expensive.
But that is how it works with monopoly capitalism and iron curtains. Ther respective empires also need cash and earn it that way with postrevolutionary cuban molasses in barrels shipped to Bohemia for refinery and then sold to Norway against “western” cash.
The russians did probably exel in cheapest vodka from it for the most.
The USA got sugar- free after Castro took over, so they had to invent a new sugar based on
home- grown and steamed corn starch. Which gives the national US sugar namely pure fructose.”corn syryp”. Different from good old sucrose from cane sugar. Fructose does not trig the healthy intact natural insuline reflex that suddenly tells you when you have enough “NO! … there must be limits to sweetness!…” Suddenly, you feel that sweetness ugly.
The fameous US obesity and all that diabetes type 1 is Gods revenge on the blockade of Cuba, you see, and the US citizens will not believe it.
In india they also use sugar cane and have not got the problem. Sugar cane is standard indian elephant food and elephants are not obese and have very good and strong teeth.
Sugar cane is to be preferred.. I got it from the Pakistani, simply chopped and dried unrefined, really a very best sugar and “sweets”. .
Proper Sucrose and Glucose is also there in dried dattes and figues and rasins and apples and plums, and natural fresh orange juice with no further problems.
So I look forward to having cuban sugar again on the free market.
Hr Rahmstorf
We were at sea today and it looks really ugly,
No seaweed no yellyfish and hardly muzzles and snails, but the seabirds still seem to thrive. I must consult the marine biological station in Drøbak where I am aquainted.. We got one tiny codfish for the cat..
There seems to be record cherry and apple harvest. It was dangerously dry in june both here and in Denmark but then it changed seemingly along with that abnormeous warmth in the northeast atlantic of this year.
As for your blueblob,….
As far as I can see it, the atlantic is overturning in the arctic ocean along with several conscistent symptoms and not southeast of Grønland., and overturning faster and faster.
See also what Jan Umsonst has written. It is interesting.
I conscider saying that your fameous blueblob is but a distal periphaere consequence and symptom. The core and the keye to the understanding of it lies in the polar basin and arctic ocean.
https://www.noaa.gov/news/ongoing-marine-heat-waves-in-us-waters-explained
“…NOAA scientists have tracked a steady climb in ocean temperatures since April 2023, which is causing unprecedented heat stress conditions in the Caribbean Basin, including waters surrounding Florida and in the Gulf of Mexico.
More isolated marine heat wave conditions have been detected off the Northeast U.S. coast, along the path of the Gulf Stream. NOAA has also been monitoring a large marine heat wave in the Northeast Pacific (in the Gulf of Alaska) that has been sitting offshore since late 2022.
As we gather more data about these events, NOAA scientists are providing answers to big questions about marine heat waves:
What are marine heat waves……
With the permission of the readers I write about my environment. Today on my beach some jellyfish. The water at 31 degrees.
This makes me happy: Cuban specialists are conducting a survey of the island along its 5,700 kilometers of coastline, aboard the MV Oceans for Youth ship.
It will carry out physical-chemical analysis of water, chlorophyll analysis and radiance and irradiance measurement.
The current state of coral reefs and the populations of large predators, the microbial loop, the presence of microplastics and the carbonate system in the water column will be evaluated.
It is good to study and understand nature but you have to act.
I am concerned that the IEA predicts that the consumption of fossil fuels will grow until 2028. If so, what IPCC scenario awaits us? + 4 degrees?
– How many were the horsemen of the Apocalypse?
– 4
Excuse my digression
@ Don Armando
We were oul and got no fish, no firefish yellyfish could be seen, The water was vey clear and the sea bottom ugly bluish white grey. with dead blueshells everywhere.
There were allways a vaste lot of seaweed yellyfishes snails shells and small crabs. as I can remember.
This happens around 20 celsius here so I do not think it is a simple function of temperature
Look for http://www.corallinales. they are everywhere, also in the arctic north of Grønland.
I have seen local bleaching on them on the rocks here. ., The corallinales seem to remain but their symbiotic algae maybe cyanobacter and red algae seems to be more sensitive.
The temperastures in the red sea is the highest. There were corals and shongi all the way acdcording to Jaques yves costeau. An in the Persian golf the temperatures swing between 15 and 35 celsius, the Australians with their barrier reef are hardly experts on this.
It may be industrial and chemical poisoning and catastrophic viral diseases rather than slitghtly elevated temperatures.
Hallo Carbomontanus,
You think that coral bleaching may be a kind of pandemy like Covid-19, only in the world of non-human living beings?
Buildup of some persistent pollutants resulting in a worldwide chemical poisoning of certain sensitive species is another interesting idea that might be, similarly as the “viral” hypothesis, perhaps also tested experimentally – although it is any time very difficult to identify a chemical species of an unknown origin / structure / composition as a true cause of an observed poisoning.
Greetings
Tom
Kalisz
It is compulsary environmental science, toxicology and virology.
I am fed up by those Australians who discuss a degree or two treshold value for full cathastrophy in their barrier reef, whereas sea temperatures with the same coral species vary way above and below that of their fameous reef. And other reefs in the world with the same and even way larger ocean temperature variations seem stable.
What about intense industrial fishery and large tourism commerce in that fameous barrier reef and what abour agricultural runoff of wild misuse of strong herbiciedes and pesticides in Australia? And further of urban and industrial wastewater with very obscure brand new efficient patent chemicals. for your lifestyle.?
And do keye species shark crocodile lobsters and whales like stedy tourism fast propellar noise and exhaust & engine coolwater?
Anti- fouling paints are being discussed here in the fjord and some of them came and were quiteb soon forbidden forbidden while it suddenly kills our purple- snails. Tetra butyl tin.
It is so easy to blame it on the climate today when rather the typical australian and other peoples rapidly changing way 0f life is to be blamed and adjusted.
“…I was soooo. big… but it went off…Pity..!” and that wyhale or sea tortoise or seal swims on wityh a ” lure” in its thoat Sport fishing is industrializes animal cruelty.
In Re to
https://www.realclimate.org/index.php/archives/2023/07/what-is-happening-in-the-atlantic-ocean-to-the-amoc/#comment-813785
Dear Carbomontanus,
Thank you very much for your explanation.
For me, it sounds logically. Although your list of possible alternative causes is impressively long, I do not see much better choice than working therethrough and checking each suspect in detail. A possibility of a negative synergy between two or even more causes should be taken into account too, I am afraid.
Greetings
Tomáš
Is not the SSP2-4.5 the “Business-as-usual” scenario? If that is the case, then look for projections for that scenario.
Armando: – “I am concerned that the IEA predicts that the consumption of fossil fuels will grow until 2028. If so, what IPCC scenario awaits us? + 4 degrees?”
In the YouTube video published on 8 Jun 2023 titled A True Paradise: WHERE WE ARE HEADING – Kevin Anderson, duration 0:16:25, climate scientist Kevin Anderson warns that continuing on our current path could result in a 3-4 °C temperature rise by the end of the century, a catastrophic outcome to be avoided at all costs. He cautions against believing the political rhetoric about progress in the fight against climate change and calls on us to push for bold policy changes. Kevin Anderson says from time interval 0:00:52:
“If we think about where we’re heading, let’s be clear, we are over 30 years, 32 years now, since the first major scientific report on climate change that came out in 1990, and so I think when we judge where we are heading, we have to say, what have we done since 1990, where we’ve watched emissions go up year after year after year. They’re now over 60% higher per year than they were in 1990. So, there is lots that you will hear, lots of rhetoric, lots of good words, lots of optimism about the future. But given we’ve known about this subject, and apparently been working on it for 30 years, the trend line tells us that we are heading towards 3 to 4 degrees Centigrade of warming across this century – an absolute climate catastrophe, and it’s a catastrophe for all species, including our own. And so that’s the direction of travel. Now, that direction of travel does not have to continue, but the current trend line tells us that all we are doing so far is giving rhetoric and optimism and greenwash, and not driving the levels of change that are necessary to stay within the 1.5 to 2 degrees framing of the ‘Paris Agreement.’”
https://www.youtube.com/watch?v=o_FtS_HNbkc
James Hansen wrote in a communication dated 13 Jul 2023 titled Peer & Public Review of “Global Warming in the Pipeline”, which included:
https://mailchi.mp/caa/peer-public-review-of-global-warming-in-the-pipeline
What’s required to avoid exceeding the +3 °C global mean warming threshold?
http://www.climatecodered.org/2023/06/three-climate-interventions-reduce.html
The painful and unfair thing about the case is that the most intelligent and farsighted are the ones who suffer the most from the decisions of the ignorant. I reckon James Hansen! , has spent 40 years rowing with the wind against the powerful
Hi Stephan, thanks for this explanation of your work and presentations, assuming the AMOC tipping point is very close, can you give any numbers estimating the climate impact for Western Europe. You say, “ So for climate impact, the AMOC is the big deal, not the Gulf Stream”, but what are the modelled numbers around temperature impact for Western Europe, or is it unknowable under current degrees of uncertainty of current climate models? Thanks.
True. Business-as-usual. Building the scenarios of the future with materials and habits from the past-present.
In the beginning, the author states that there is roughly a 10 percent chance of all of this happening.
100-10=90.
There a 90 percent chance that none of this will ever happen.
dd: – “In the beginning, the author states that there is roughly a 10 percent chance of all of this happening.”
dd, would you:
* Live/work in a building that had a 10% chance of collapsing?
* Cross a bridge that had a 10% chance of failing?
* Travel on an aircraft that had a 10% chance of crashing?
* Travel in a vehicle that had a 10% chance of the steering/brakes failing?
dd, do you think a 10% risk of a catastrophic failure event, consequently affecting your wellbeing or potentially ending your life, would be acceptable in your daily life? Do you feel lucky?
David Spratt wrote in a piece titled IPCC: a gamble on earth system failure, dated 30 Mar 2023, which included:
https://johnmenadue.com/ipcc-a-gamble-on-earth-system-and-human-civilisation-failure/
A 1o percent change for possible devastating consequences is quite a risk, especially per #8 “Standard climate models probably underestimate the risk”. Think of tornado risks. A 10 percent chance of a tornado would warrant a high risk from the Storm Prediction Center in Oklahoma.
Indeed. If there were a 10% chance of every airliner crashing, there would be no airline industry. Heck, that would be true at 1%, and probably 0.1%, too.
There are higher risks I must say, and that temperature is not the highest risk and most alarming thing.
I rather just keep it as an indicator of the situation that is pointing at other risks.
It is important for us, I believe, to have also other aspects of climate in our thoughts and speculations, , that we are better able to look ot for and follow, for ourselves. Well understood and reliable , official things that are functions of the temperatures and of the climate.
That is also traditional, sceptical peasant wisdom.
Dr Rahmstorf was quoting previous estimates that the risk of the AMOC collapsing before 2100 is 10 percent. This does not mean that the odds of a collapse never occurring are 90 percent. In fact, the risk of collapse increases to 50 percent by 2300 under high emission scenarios based on previous estimates. The point of the article though is that these estimates need to be revised and the risk in this century is much greater.
Thanks Stefan, here in the UK the petro-terrorists in our Govt are insistent it’ll be too expensive to save the planet…..what can you do?
Anyway, this paper has popped up a few times in online discussions. I was wondering what your view is:
North Atlantic Oscillation contributes to the subpolar North Atlantic cooling in the past century https://link.springer.com/article/10.1007/s00382-023-06847-y
Is there a connection between AMOC slowdown and locked-in weather patterns? LIke the heat domes stuck over a lot of the US this summer and here in New Zealand’s North Island we had “a rain dome” summer that resulted in slips and flooding through January and February.
Dear Susan
So you live in New Zealand, that is near diametric to me, How interesting in the climate.
I believe that slowdown of the AMOC is rather a professionally and geographically provincial wiew, and that major “overturnings” of the Atlantic is just finding other patterns, where fameous popular political & commerciallized patterns and “trade winds” may be vanishing.
What seems more real and thus more important and what I also know from Chladni plates and wind instrument acoustics is “Locked in weather patterns”. That has been reported for some years now and that are physically plausible at major temperature change in the global system.
I think we should rather look at that and try and give that a physical explaination.
Weather patterns seem to remain stronger and out of normal traditional seasons, or fail to come at normal traditional time.
This is known as “dispersion unlinearity and hysteresis” in material & energetic streaming and oscilolating systems with patterns.
@ susan
even more interesting when I look closer.
“…..that resulted in slips and floodingt through january and february…”
Yes! And i have been selling the same in july and august from Norway.
How diametrical….
It must have a common cause!
Cold or cool weather kills far more people worldwide that warm or hot weather.
In the world there are around 4.6 million people dying from cold-related causes every year mostly from increased strokes and heart attacks compared with about 500,000 dying from heat-related causes. When people breathe in cool or cold air it constricts the blood vessels leading to increased strokes and heart attacks.
‘Global, regional and national burden of mortality associated with nonoptimal ambient temperatures from 2000 to 2019: a three-stage modelling study’
https://www.thelancet.com/journals/lanplh/article/PIIS2542-5196(21)00081-4/fulltext
This paper from 2015 says that cold-related deaths exceed heat-related deaths by 20-1.. It says that moderately cold and hot weather kills far more people than extreme hot and cold weather.
‘Mortality risk attributable to high and low ambient temperature: a multi-country observational study’ https://www.thelancet.com/journals/lancet/article/PIIS0140-6736(14)62114-0/fulltext
RG: Cold or cool weather kills far more people worldwide that warm or hot weather.
BPL: Very true, But cold deaths are declining and heat deaths are increasing fast. Thus the attention paid to them. Man bites dog.
@ Levenson & al
No! I believe superstition is loose here.
Look at life expectance in warm and cold climates.
Then wake up and remember Malaria and tropic diseases. Also bad infrastructures, unemployment, powrity, and hopeless depts and slums.
Does that thrive in warm, or rather in chill climates? May that first of all be unhealthy and mortal?
May perhaps manmade mortal misery be a consequense of hot rather than of cold climates? If that is true, which I believe it is, then we have a better formula for explaination, and possible cure perhaps.
Then an old rumor: Iden des März, Ides of March, IDVS MARTIÆ. see Wikipedia.
When Julius Cæsar was murdered and also Adolf Hittler died at last.
It is known here as Vårknipe, in english Hungry gap.. And Ides of March known as when all goes wrong and people and animals normally die namely late winter.. See also Lent… for 40 days and when.
But that is a biorythm of rather “astrological” nature. Early political calendars were also astrologically anchored the best they could and understood.
When it happens in Ur in Caldea and in Roma and Jerusalem at approximately the same time of the year and less in Copenhagen and Oslo, then it is hardly related to abs. temperatures in the climates, and more to oecological biorythms & economical rythms and sub- sequent political astrologies & religions connected to that.
We must ask Australia, New Zealand, and Argentina for control first, before we believe or suggest anything about this.
Ralph Gardner: – “Cold or cool weather kills far more people worldwide that warm or hot weather.”
Per your first reference for the Jul 2021 Lancet study, below the sub-heading Results, it began with:
It seems to me the majority of countries/locations selected in this study appear biased towards the cooler end of the mean annual temperature (MAT) spectrum, so I’m not surprised by the results. Where are more of the hotter countries in this study? There’s only one African country included (see Figure 1). None of the central African countries appear represented. Perhaps the reason is because of a lack of data?
Ralph, I think one should be cautious about making such bold statements without adequate data that’s sufficiently representative for the “worldwide” human population.
What I think would be interesting to see is a graph correlating hot- or cold-related deaths with the MATs for those locations in the study.
As climate change continues warming the planet, a new and invisible killer is emerging: extreme wet bulb temperatures. This refers to a potentially lethal combination of heat and humidity that, until now, have appeared somewhat infrequently around the world. But models predict that they are likely to become an increasingly big problem in the coming years. See the YouTube video published by PBS Terra on 10 May 2023 titled Too HOT and HUMID to Live: Extreme Wet Bulb Events Are on the Rise, duration 0:10:42.
https://www.youtube.com/watch?v=vqBrL8BokSk
Most people around the world don’t have access to air-conditioning. The hotter it gets, the bigger the divide between the cool and the damned.
You may wish to check out the YouTube video titled Jeff Goodell — The Heat Will Kill You First: Life and Death on a Scorched Planet, published Aug 4, duration 1:03:05. Watch author Jeff Goodell ‘s book talk and reading at Politics and Prose book store in Washington, D.C. There’s also included a Q&A with the audience.
https://www.youtube.com/watch?v=NMNhGnSLhIQ
Ralph Gardner
“Cold or cool weather kills far more people worldwide that warm or hot weather.”
This maybe so, but I suggest you read the following commentary:
Climate change (global warming) won’t reduce winter deaths.
23 February 2014
“Climate change is unlikely to reduce the UK’s excess winter death rate as previously thought.
A new study, published today in Nature Climate Change, debunks the widely held view that warmer winters will cut the number of deaths normally seen at the coldest time of year.
Analysing data from the past 60 years, researchers at UCL and the University of Exeter looked at how the winter death rate has changed over time, and what factors influenced it.
They found that from 1951 to 1971, the number of cold winter days was strongly linked to death rates, while from 1971 to 1991, both the number of cold days and flu activity were responsible for increased death rates. However, their analysis showed that from 1991 to 2011, flu activity alone was the main cause in year to year variation in winter mortality.
Lead researcher Dr Philip Staddon says: “We’ve shown that the number of cold days in a winter no longer explains its number of excess deaths. Instead, the main cause of year to year variation in winter mortality in recent decades has been flu.”
Climate change appears unlikely to lower winter death rates. Indeed, it may substantially increase them by driving extreme weather events and greater variation in winter temperatures. Action must be taken to prevent this happening.
Professor Hugh Montgomery (UCL Institute for Human Health & Performance)
The team suggest that this reduced link between the number of cold days and deaths in a winter can be explained by improvements in housing, health care, income and a greater awareness of the risks of the cold.
As climate change progresses, the UK is likely to experience increasing weather extremes, including a greater number of less predictable periods of extreme cold. The research highlights that, despite a generally warmer winter, a more volatile climate could actually lead to increased numbers of winter deaths associated with climate change, rather than fewer.
Dr Staddon believes the findings have important implications for policy: “Both policy makers and health professionals have, for some time, assumed that a potential benefit from climate change will be a reduction in deaths seen over winter. We’ve shown that this is unlikely to be the case. Efforts to combat winter mortality due to cold spells should not be lessened, and those against flu and flu-like illnesses should also be maintained……..”
https://www.ucl.ac.uk/news/2014/feb/climate-change-wont-reduce-winter-deaths#:~:text=Climate%20change%20appears%20unlikely%20to,taken%20to%20prevent%20this%20happening.
So it looks to me like we are heading into a global situation with increasingly severe heatwaves and associated increased mortality, especially in poor tropical countries that struggle to afford air conditioning and where many people have to work on farms, but no or little compensating decrease in mortality from warmer winters in temperate and very cold regions. And throwing in another factor, if the AMOC stops Europe then have to spend huge resourcers trying to adapt to a much colder climate and god knows what that will do to their agriculture. This is not a good situation overall, if you cant work it out for yourself.
Nigelj
You got it.
…”The main cause of year to year variation of winter mortality in recent decades has been flu!”
Flue virus survive better at cooler temperatrures and are quite stable and can be kept for longer time in the refrigerator.
It is eaten in the wild by other and more geedy microbes as soon as it is warm enough in the natural substrates.
Then in winter especially at deep chill, people keep together hand in hand chin by chin coughing, in tight rooms with electric heating and no ventilation to save heat costs, and sneezing.
To all and everyone
On whether cool and warm weathers are killing more or less people.
I believe most of you are ignorant and supersticious here. being flat earthers, blind believers in the scriptures , and desert walkers. in the politics.
You are believing in rumors, that most people will freeze in Hell, Thus Big Coal should be defended.
Where does it rot? where are the worlds unhealthy climates and slums” Where is life exspectance higher uphill or downhill? In the sub-arctics or at the eqvator?
Where is there Malaria, malnutricion and lack of infrastructure and of justice?? What and where are the worlds developed and underdeveloped “developing” nations?
Do not swallow cheap supersticion and propaganda from the denialists and surrealists about theese things.
Homom Sapiens knew how to dress, thus conquered all the alternatives and invaded allmost all climates. exept that one above 35 celsius wetbulb temperatures.
Way more people die of feever and of hotheads, than of hypothermia.
Im Studierzimmer,
Mephisto
…und immer zirkuliert ein neues frisches Blut.
So geht es fort, man möchte rasend werden!
Der Luft, dem Wasser, wie dem Erden
enwickeln tausend Keime sich
Im trocknen ,Feuchten Warmen Kalten!
Hätt ich mir nicht die Flamme vorbehalten,
ich hätte nichts aparts für mich.
SANN!