The Gulf Stream

Quite often in the media there will be articles claiming that global warming could cause the Gulf Stream to shutdown, or collapse. This is technically not correct, which is explained really nicely, in the video below, by Sabine Hossenfelder.

Essentially, the Gulf Stream is driven by the rotation of the Earth, so simply cannot shutdown. What the news reports are typically referring to is the Atlantic Meriodional Overturning Circulation (AMOC), which is a complex circulation network that carries warm water from the equator towards the north pole, and cold water from the pole back towards the equator. The concern is that as the ice at the pole melts, the water becomes less salty and less dense, making it harder for it to sink and drive the AMOC.

However, as the video below highlights, even if the Gulf Stream can’t shutdown, the AMOC does push it to higher latitudes. Hence, a slowdown of the AMOC could move the Gulf Stream to the south and could cool parts of Europe by up to 5oC. So, even if the Gulf Stream can’t shutdown, it can still be infuenced by global warming.

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30 Responses to The Gulf Stream

  1. Willard says:

    So when are you starting your video series, AT?

  2. I thought the next step after blogs was podcasts 🙂

  3. Dan Hughes says:

    Fluid motions on the surface of a rotating roughly spherical body, plus the BCs represented by the solids bounding the motions.

  4. Dan,
    Not quite sure what your comment is getting at.

  5. Ben McMillan says:

    I’m feeling like this is a little too pedantic about exactly what the name of the thing is that will slow/shut down/move and possibly leave Europe 5C colder. Although at least there is a lot of useful information lurking in a somewhat unnecessarily combatitive framing.

    Not like these currents are fully distinct and decoupled bits of water anyway, they are really processes rather than physically separate objects, and they are processes that interact in a non-trivial way.

  6. Greg Robie says:

    The strawman fallacy?

    My read of the reported fast-to-slow shift the AMOC does have a record of doing is consistent with observation data of the slow down that is likely in progress. The data is not robust (British scientists on British Navy submarines have documented a reduction of 12 downwelling sites to three in a report – likely in the ‘00s. While the reporter could have more clearly associated the term collapse with the shift from fast to slow, any argument that, it can’t stop seems specious.

    The slowing AMOC has immediate consequences for costal flooding in the US Northeast (and I speak from experience due to property I had flood nothin Irene and Sandy – 4’ and 2’ respectively). The 4’ inundating confirmed FEMA flood map’s determination that base flood elevation (BFE) for my shop is 10’ above mean high tide. A subsequent Sandy-like backing up of the Hudson River will require a sea level rise of about 2’ before the map will need to establish a new BFE. (The size of a watersheds drainage opening under the west shore railroad track retains the current BFE until that 2’ sea level is passed.

    Jason Box recent paper establishing a metric for a more robust factoring in of Greenland’s ice sheet dynamics and sea level rise ALSO could help inform the increasing runoff’s purbation of the AMOC … and adds to the northern flow of tropical heat toward and into the Arctic Ocean system.

    A rapidly warming Arctic has had the Northern Polar Jet perturbed relative to its apparent Holocene pattern, and this for about eight years relative to the mid-Hudson Valley’s weather/climate. On timescales that relate to the sustainability of the academic system that emploies astrophysicists, the North Alantic’s ocean currents shifts that correlate with the slowing are, and as reported, complex (& rationally terrifying regarding privileged homeostasis and our trusted economic meme).

    …and this improvement in understanding ice sheet dynamics does not happen in a vacuum. The purbation of the Arctic’s seasonally increasing solar insolence due to tropopause lift is an omitted-by-climate-modeling-convention that is a hidden-in-plain-sight primary purbation of our planet’s climate system within the carbon pulse of our social industrialization.


  7. Ben,

    I’m feeling like this is a little too pedantic about exactly what the name of the thing is that will slow/shut down/move and possibly leave Europe 5C colder. Although at least there is a lot of useful information lurking in a somewhat unnecessarily combatitive framing.

    Indeed, I had a similar thought. I quite like these clarifications from a physics perspective, but it’s not as if global warming can’t shutdown/slow the gulf stream doesn’t mean that can’t change it in a way that will have a big impact.

  8. Willard says:

    > Not quite sure what your comment is getting at.

    I think it is the point, and I suspect it might be better that way.

  9. russellseitz says:

    Whatever Gulf Stream heat transport’s future , it already has the capacity to amplify storm damage in the eponymous Gulf. Just as Katrina grew in force overnight passing along the 30+˚ C waters of the Stream en route to inundating New Orleans in 2004, Hurricane Ian spun up lethally past 200 KPH on encountering the same loop of hot Gulf water last year.

    The population density of the Gulf Coast has continued to soar despite thousand of storm surge fatalities, and property damage enough to make an honest broker of Roger Jr.

  10. Ben Mc says:

    I’m feeling like this is a little too pedantic about exactly what the name of the thing is that will slow/shut down/move and possibly leave Europe 5C colder. Although at least there is a lot of useful information lurking in a somewhat unnecessarily combatitive framing.

    ATTP says: Indeed, I had a similar thought. I quite like these clarifications from a physics perspective, but it’s not as if global warming can’t shutdown/slow the gulf stream doesn’t mean that can’t change it in a way that will have a big impact.

    Mike says: yeah, I think we should be careful not to allow people to misunderstand the possible impacts of global warming. When the headlines say “the Gulf Stream” will stop, we can gently clarify that the AMOC is the actual thing that could turn off, so let’s discuss how that might happen and what it would mean. Too much discussion about how the rotation of the earth will continue to create “a gulf stream” will open the door for charlatans to repeat the statement that the gulf stream cannot actually stop and let the charlatans confuse the electorate to believe that the dangers of global warming are not real and remarkably bad for earthlings.

    We are not a very bright species. The headline news should be that we continue to move forward into a global climate experiment with a sudden pulse of CO2 and other GHGs being emitted into the atmosphere. The next sentence in this news story should be that “there has never been an event like this in the planetary record except for times of great volcanic eruptions in a short period of time or moments when the planet got a direct hit from a relatively large comet.

    I think the scientific discussion and presentation needs to be done at the level of a 5th grader in the USA or it will not be understood by a sufficient number of voters required to vote for safety from the global experiment we have been running since we started burning coal and other fossil fuels.

    If the global climate discuss and presentation is delivered with a lot of reference to the difference between the gulf stream and the AMOC, I believe that 50% or more of the eligible voters in the USA will simply not understand the risks and dangers we have created with our greenhouse gas experiment. Keep it simple, stupid. KISS. That used to be a warning that folks followed when doing computer work and programming. I think the same applies here with AGW. Discussion of the AMOC or Milankovitch cycles should be relegated to the absolute bottom of the news stories. The top four or five paragraphs need to keep it simple and lead with the GH gas experiment that we accidentally initiated a while back and discuss why we need to stop adding fuel to this fire now because the consequences are going to be dire. We are already feeling the impacts. We have to stop adding GH gases to the global system.

    Ms. Hossenfelder’s lovely presentation is delivered at high school level or maybe even first year in college. It’s accurate and should work for the 40% of the electorate who function at that level. We have to understand that distinction as well as we understand the difference between the AMOC and the Gulf Stream or we risk catastrophe.

    Recent readings indicate that we have increased annual atmospheric CO2 content by 2.5 ppm and that we have already passed into dangerous territory with concentrations of over 415 ppm. Keep it simple. Talk to 5th graders to figure out the level of sophistication that should be included in the presentation. Anything significantly above that level simply will not move the needle.



  11. verytallguy says:

    “I think it is the point, and I suspect it might be better that way.”

    Quite remarkable what utter crap Judith Curry promotes.

  12. Chubbs says:

    The video struck a chord. Simple physics explains the main features of the atmosphere. Chaotic motion is a distraction impacting weather but not major circulation features. Climate response is also simple physics. Turn up the forcing knob and in the short-term the world warms linearly. We have enough data to know the warming is fast enough to move the climate needle.

    As discussed briefly in the video, the main problem in climate modeling is the response of earth systems like ice sheets, permafrost, forests etc. to climate change. We don’t have observations and the climate system is too complex to model. As Sabine says we are participating in a science experiment.

  13. Sabine is a bit facile concerning the direction of the winds. Along the equator, the stratospheric winds are not predictable in their direction, as they will temporarily reverse in quasi-two year cycles. If it was simply the earth’s rotation, they would maintain the same direction, but the fact that they completely reverse is still mysterious. Don’t let atmospheric scientists such as Richard Lindzen and the infamous Tim Dunkerton convince you that they understand why.

  14. jacksmith4tx says:

    In the polar regions a SSW (sudden stratospheric warming) event can stop and reverse the stratospheric polar winds in just a few days. A SSW was responsible for the great winter storm Uri in 2021. There is another (weaker) SSW coming soon.

    The history of observing and measuring SSW events is very short as they were a completely unknown phenomenon prior to the late 1940s. Strong events can briefly alter the composition of atmosphere by displacing huge masses of ozone and disruption electromagnet fields. As atmospheric disruptions go these SSW events are like hurricanes but since nobody lives @ 40km above the planet they were invisible. Just the huge amount of heat transported by these events almost guaranties abnormal weather on the surface. Too bad there is no such thing as palo-meteorology. I suspect there is a climate change link.

  15. Steven Mosher says:


    i think ATTP
    should do something like this

    regular guests: zeke, Rhode, Box, Gavin,

    take a look at the format.

  16. Richard Arrett says:

    smallbluemike says “We have to stop adding GH gases to the global system.”

    You go first. How do you heat your home? What do you drive? Do you fly? Do you breath? I don’t think it is feasible for humanity to “stop adding GH gases to the global system”. We can lower GH emissions but we cannot stop emitting (unless you want to stop breathing – I do not).

  17. Richard Arrett says:

    I was just pointing out the impossibility of not “adding GH gases to the global system”. But fine – I will drop it.

  18. Willard says:

    Thanks, Rick.

    Since I know you dispute that blankets warm, it might be better that way.

  19. But just to answer Rick’s question about how we stop adding greenhouse gases, the answer is carbon tax. It’s not an individualized problem that we can solve. We have to solve it through large group action and that means monetary incentives. Stick and carrot.



  20. Bob Loblaw says:

    Unfortunately, small, I think that Richard’s confusion is is due to an inability to understand the concept of “net flux”. When you say “adding”, you mean “not putting anything there that wasn’t already there recently”. Breathing returns carbon that was recently removed. Richard seems to think only in terms of a single flux directed into the atmosphere (breathing), not a cycle (as Willard’s previous post points out).

    Of course, if Willard’s comment about Richard not believing that blankets warm is correct, then there are probably a lot of things in climate science that Richard fails to understand. Rejection of the blanket analogy is typically the result of not understanding net IR flux.

  21. Ken Fabian says:

    Rick, having no emissions lifestyles is the end goal, not the start point. It is a goal that appears to be achievable by making our primary energy supplies zero emissions. Even partial success will prevent the accumulation and persistence of worst case ongoing harms.

    No-one should have to make a show of going stone age to have the right to call for government coordinated, economy-wide actions to address a problem that governments know full well is real and very serious. But would people making arguments like you have made take anyone seriously who was that fanatical? I suspect they would be more subject to mockery by the same self appointed hypocrisy police who demand zero emissions from “activists” as some kind of proof of their sincerity than given greater respect. Speaking of hypocrisy.

  22. Richard Arrett says:

    Language is important. I did read “add” as adding more greenhouse gases to the atmosphere. I did not understand mike to be talking about net flux or the carbon cycle. So I read mike as calling for zero emissions from humanity – which I think is impossible.

    As to a blanket warming. I do not think blankets warm. I think they insulate. Which is quite different to warming. But you do you.

  23. Bob Loblaw says:

    Word games, Richard.

    “When I use a word,” Humpty Dumpty said, in rather a scornful tone, “it means just what I choose it to mean—neither more nor less.”

    “The question is,” said Alice, “whether you can make words mean so many different things.”

    “The question is,” said Humpty Dumpty, “which is to be master—that’s all.”

  24. Willard says:


    I think it’s safe to say that we all know that language is a social art. Following through the full “cycle” of the exchange will only “add” more Climateball to the world.

    If we could reach Climateball Zero, that’d be great.

  25. Richard Arrett says:

    [Playing the ref. But Semantics is boring, Rick. Please keep parsomatics at Lucia’s. -W]

  26. Susan Anderson says:

    Lovely to have that additional information after seeing the Guardian article and trying to get my aging brain to follow it. Up to this point, my opinion had been that I already saw the slowing of the AMOC in the early aughts when I was making an annual spring trip to Cornwall. And that there will be further slowing, but not a stop in the foreseeable future (which would be a hundred and a few more years from now).

    I’ll be taking a deep dive into the material, for which thanks.

    About that SSW event (23 January), Jack Smith’s cite is not at the level of a 5th grader, but full of pictures (I love visuals) and very informative; I have been imbibing it as best I can for a few days:

  27. Susan Anderson says:

    Now having watched the video, I’d say it’s amazingly informative. And obviously I confused the Gulf Stream with the AMOC – at least some – above.

  28. Dan Hughes says:

    Christian Schoof, Sue Cook, Bernd Kulessa, and Sarah Thompson (2021), “The drainage of glacier and ice sheet surface lakes.” arXiv:2110.15495v1 [physics.flu-dyn] 29 Oct 2021,

    Equation (1g)

  29. Dan Hughes pushing a model of melting water throughput at Climate Etc. Much too mathematically complex. The actual way to think about it is like a dam — it will hold water until it doesn’t. Water has to go somewhere.

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