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I’m a physical oceanographer. While I have only skimmed this article I would like to make two quick comments. 1) The AMOC is one of the most studied parts of t

I’m a physical oceanographer. While I have only skimmed this article I would like to make two quick comments. 1) The AMOC is one of the most studied parts of the world ocean and predictions about its collapse have been made since Stommel in 1961. I think in general any study on its imminent collapse should be taken with a grain of salt and it would be wise to wait for further replication and the consensus of the community. You can google AMOC collapse and find articles stretching back decades. 2) This may be my bias a dynamacist but I am skeptical of purely statistical models of AMOC collapse. The AMOC is complex and trying to predict the time of a complete collapse is a significant simplification (especially when, as the authors note, a slowdown rather than shutdown of the AMOC seems more likely from our current understanding). Nevertheless this is a very interesting study and contribution to the field. Edit: @abathur posted a wonderful link below that I wanted to spread further: https://www.sciencemediacentre.org/expert-reaction-to-paper-warning-of-a-collapse-of-the-atlantic-meridional-overturning-circulation/ https://www.sciencemediacentre.org/expert-reaction-to-paper-...

retrocryptid 3y ago
Are you comparing Stommel's Box model to Bower's recent work? I would argue the latter is more "expressive" though yes, it depends on measurements we weren't collecting in the 60s.
- oceanthrowaway 3y ago
  No I am just noting that the AMOC bistability literature is decades long.
  - bhouston 3y ago
    So is the climate change literature, it stretched back decades before we had concrete evidence that it was happening. Just because something is long predicted to be a risk by experts in a field, doesn't mean its likelihood of happening goes down. I right read about AMOC back in 1997 while in university. It was fascinating and frightening back then. Still relevant today. It would be sad if it did actually end up happening in my lifetime, but humans are notoriously bad at reacting to bad things that might happening in the future - https://en.wikipedia.org/wiki/Tragedy_of_the_commons https://en.wikipedia.org/wiki/Tragedy_of_the_commons. We tend to only really react once the bad thing has happened.
Terretta 3y ago
The terms "imminent" and "predict the time" seem like missing the point of the article you acknowledged you have only skimmed. I felt the article was clear collapse is not imminent, not even in this century. I felt it noted focus was not on imminence, but on changes worth mentioning in aspects of interest. Perhaps the difference is this article is talking of timing for transitions of significance, rather than the forthcoming collapse more likely to arrive sooner after such transitions?
- oceanthrowaway 3y ago
  You are completely correct I regret that word choice now. I was rushing to comment because I felt it was important to provide context on AMOC collapse scholarship.
  - refulgentis 3y ago
    Memento mori: top comment made the same mistake[1], your contributions reinforced the top comment, and your separate individual reply is the second comment. Rushing to comment has deep effects on HN, the threading incentivizes appending to the top comments rather than replying. This will now be a philosophical debate about scientific trust for hours just because people assume the article says "collapse is happening shortly by X date", but its just a statistical model :( Don't mean to make you feel bad or call you out, most people don't read the article if it's popular. It's my attempt to give a little back to the community to note it, been here a very long time, and when people try calling it out coarsely it isn't constructive. [1] sort of: they understood it was a statistical model but spent so much time hand-wringing about Nature publishing a statistical model that it came off like there was something wrong with the article, causing a rush of replies of "how can I trust anything??"
    - oceanthrowaway 3y ago
      Thank you for your kind tone (genuinely). I understand your concern. I certainly hope it does not become a debate about scientific trust for hours although you are right its headed that way. I have a great amount of trust in the scientific consensus, am a publishing climate scientist myself, and did genuinely enjoy this paper. It is my opinion that is instructive for people to know that studies on AMOC collapse are often misinterpreted when they are spread widely, similar maybe to headlines about experimental new battery designs. I do not think that the authors of the study have any ill intent or that their work is unimportant, but rather that AMOC collapse is an incredibly complex topic and that when studies on it are often posted to sites like hacker news (https://news.ycombinator.com/item?id=28085342 https://news.ycombinator.com/item?id=28085342 I have been here a decade just not on this throwaway ;) ) they are often taken as a significant change in the understanding of the field which they are not (yet at least). I see your point that harping on this fact is perhaps boring and repetitive so I apologize for that.
bhouston 3y ago
If you are a real oceanographer, why are you anonymous and using a throw away? You want to both use your credentials to be taken seriously in your posts, but also you want to avoid too much scrutiny of who you are.
- GeoAtreides 3y ago
  I also commented something similar, before seeing your comment. Not sure why people are eager to believe literally some guy on the internet. Maybe the people are afraid to believe the other guys, you know, the ones published in Nature.
- mistermann 3y ago
  > You want to both use your credentials to be taken seriously in your posts, but also you want to avoid too much scrutiny of who you are. Apply some philosophy on top of your "science" and you may learn something new and potentially interesting about your claim.
thumbuddy 3y ago
So say it does collapse, in layman's terms what does that mean?
- colechristensen 3y ago
  Europe would get cold. Ocean currents bring lots of warm water from the south towards Europe making it quite a bit warmer than other places at similar latitudes. Cities in Europe are quite a bit further north than most people think. Lots of other side effects as well would happen but be less known or surely predicted by models.
  - deleted 3y ago
    [deleted]
  - novaRom 3y ago
    Clear skies and drier weather should result in reduced cloud cover, which allows more direct sunlight to reach the surface during the day, leading to warmer temperatures. During the night, the lack of cloud cover also means there is less insulation to trap the heat accumulated during the day. This can lead to hot days and relatively cooler nights, which can be characteristic of certain climates, like in arid or desert regions.
  - CPLX 3y ago
    Not just colder, also drier right?
- novaRom 3y ago
  Current stable pattern changes into another stable one, probably quickly. Or it may split into two independent stable patterns. It will not disappear. It may result in long term climatic changes in different geographies, especially during transition, although it would be rather quick.
  - thumbuddy 3y ago
    Thanks for explaining that. I guess what I'm asking is... Will the sea life likely be okay? Human life? More hurricanes? No one knows?
joshuaheard 3y ago
The article says the collapse would cause an ice age in Northern Europe. Would that "cure" global warming?
- JPLeRouzic 3y ago
  I can't find any reference to ice age in the article, nor to consequences for Europe, where did I missed them?
  - joshuaheard 3y ago
    I've read several articles on this today. It must have been another one.
- dotancohen 3y ago
  No. Global warming is the effect of decreased solar radiation (as compared to how much solar energy is absorbed), thus more energy added to the Earth. A new ice age in Norther Europe might slightly increase that area's albido, which would increase solar radiation and in theory mitigate global warming. But truth is, the effect of that change in albido will be very small compared to the effect of the atmospheric CO2 (which traps the solar radiation). Europe may be colder, but somewhere else is going to be much, much hotter.
  - joshuaheard 3y ago
    You would think that adding that much ice in the atmosphere would cool it down a little, like putting an ice cube in a glass of water.
    - dotancohen 3y ago
      Where do you think that the "cold" in the ice comes from? It's just moving heat from one part of the planet to another. The total amount of heat entering the Earth is increasing, cold spots not withstanding.
chiefalchemist 3y ago
Since you're familiar with this stuff, and I didn't see it in the article, what's the impact if it were to collapse? To the ecology? To the weather? To other ocean currents?
GeoAtreides 3y ago
[flagged]
- PKop 3y ago
  You'd love to ruin his career and publicly shame him for having incorrect views wouldn't you? Awarding credibility on the basis of having a public face is absurd, and it's trivial to conceive of the way that could be politically silencing of dissident views, or that lack of anonymity would incentivize sticking to consensus. People disagree anonymously on the internet all the time, since the beginning. Are you incapable of judging the merits of an argument without requiring some appeal to authority?
  - tarsinge 3y ago
    What is there to judge? The original commenter is the one making an appeal to authority, then just saying they are skeptical. In short an anonymous giving their opinion. The parent is right saying it’s of way lower value than the study.
    - PKop 3y ago
      Because a study lays out a more thorough and detailed argument, not because someone's real name or credentials are attached. The crux of my disagreement was his claim a name attached to an argument a priori makes it more valid than one that is anonymous. In a highly politicized environment, it can possibly be argue that a real name makes it less credible and more likely to be consensus. Putting that aside, it certainly doesn't it make it more credible.
- oceanthrowaway 3y ago
  I’m maybe overly cautious about my online footprint. I understand your skepticism and think it’s well placed. For what it’s worth I don’t see my comment as FUD and would wager that the authors of the study would agree with my comment. I enjoyed their study and was just trying to provide additional context (see also the link in my edit). You are totally right that my comment is worth significantly less than a peer reviewed study.

retrocryptid 3y ago

Are you comparing Stommel's Box model to Bower's recent work? I would argue the latter is more "expressive" though yes, it depends on measurements we weren't collecting in the 60s.

oceanthrowaway 3y ago
No I am just noting that the AMOC bistability literature is decades long.
- bhouston 3y ago
  So is the climate change literature, it stretched back decades before we had concrete evidence that it was happening. Just because something is long predicted to be a risk by experts in a field, doesn't mean its likelihood of happening goes down. I right read about AMOC back in 1997 while in university. It was fascinating and frightening back then. Still relevant today. It would be sad if it did actually end up happening in my lifetime, but humans are notoriously bad at reacting to bad things that might happening in the future - https://en.wikipedia.org/wiki/Tragedy_of_the_commons https://en.wikipedia.org/wiki/Tragedy_of_the_commons. We tend to only really react once the bad thing has happened.

Terretta 3y ago

The terms "imminent" and "predict the time" seem like missing the point of the article you acknowledged you have only skimmed. I felt the article was clear collapse is not imminent, not even in this century. I felt it noted focus was not on imminence, but on changes worth mentioning in aspects of interest. Perhaps the difference is this article is talking of timing for transitions of significance, rather than the forthcoming collapse more likely to arrive sooner after such transitions?

oceanthrowaway 3y ago
You are completely correct I regret that word choice now. I was rushing to comment because I felt it was important to provide context on AMOC collapse scholarship.
- refulgentis 3y ago
  Memento mori: top comment made the same mistake[1], your contributions reinforced the top comment, and your separate individual reply is the second comment. Rushing to comment has deep effects on HN, the threading incentivizes appending to the top comments rather than replying. This will now be a philosophical debate about scientific trust for hours just because people assume the article says "collapse is happening shortly by X date", but its just a statistical model :( Don't mean to make you feel bad or call you out, most people don't read the article if it's popular. It's my attempt to give a little back to the community to note it, been here a very long time, and when people try calling it out coarsely it isn't constructive. [1] sort of: they understood it was a statistical model but spent so much time hand-wringing about Nature publishing a statistical model that it came off like there was something wrong with the article, causing a rush of replies of "how can I trust anything??"
  - oceanthrowaway 3y ago
    Thank you for your kind tone (genuinely). I understand your concern. I certainly hope it does not become a debate about scientific trust for hours although you are right its headed that way. I have a great amount of trust in the scientific consensus, am a publishing climate scientist myself, and did genuinely enjoy this paper. It is my opinion that is instructive for people to know that studies on AMOC collapse are often misinterpreted when they are spread widely, similar maybe to headlines about experimental new battery designs. I do not think that the authors of the study have any ill intent or that their work is unimportant, but rather that AMOC collapse is an incredibly complex topic and that when studies on it are often posted to sites like hacker news (https://news.ycombinator.com/item?id=28085342 https://news.ycombinator.com/item?id=28085342 I have been here a decade just not on this throwaway ;) ) they are often taken as a significant change in the understanding of the field which they are not (yet at least). I see your point that harping on this fact is perhaps boring and repetitive so I apologize for that.

bhouston 3y ago

If you are a real oceanographer, why are you anonymous and using a throw away? You want to both use your credentials to be taken seriously in your posts, but also you want to avoid too much scrutiny of who you are.

GeoAtreides 3y ago
I also commented something similar, before seeing your comment. Not sure why people are eager to believe literally some guy on the internet. Maybe the people are afraid to believe the other guys, you know, the ones published in Nature.
mistermann 3y ago
> You want to both use your credentials to be taken seriously in your posts, but also you want to avoid too much scrutiny of who you are. Apply some philosophy on top of your "science" and you may learn something new and potentially interesting about your claim.

thumbuddy 3y ago

So say it does collapse, in layman's terms what does that mean?

colechristensen 3y ago
Europe would get cold. Ocean currents bring lots of warm water from the south towards Europe making it quite a bit warmer than other places at similar latitudes. Cities in Europe are quite a bit further north than most people think. Lots of other side effects as well would happen but be less known or surely predicted by models.
- deleted 3y ago
  [deleted]
- novaRom 3y ago
  Clear skies and drier weather should result in reduced cloud cover, which allows more direct sunlight to reach the surface during the day, leading to warmer temperatures. During the night, the lack of cloud cover also means there is less insulation to trap the heat accumulated during the day. This can lead to hot days and relatively cooler nights, which can be characteristic of certain climates, like in arid or desert regions.
- CPLX 3y ago
  Not just colder, also drier right?
novaRom 3y ago
Current stable pattern changes into another stable one, probably quickly. Or it may split into two independent stable patterns. It will not disappear. It may result in long term climatic changes in different geographies, especially during transition, although it would be rather quick.
- thumbuddy 3y ago
  Thanks for explaining that. I guess what I'm asking is... Will the sea life likely be okay? Human life? More hurricanes? No one knows?

joshuaheard 3y ago

The article says the collapse would cause an ice age in Northern Europe. Would that "cure" global warming?

JPLeRouzic 3y ago
I can't find any reference to ice age in the article, nor to consequences for Europe, where did I missed them?
- joshuaheard 3y ago
  I've read several articles on this today. It must have been another one.
dotancohen 3y ago
No. Global warming is the effect of decreased solar radiation (as compared to how much solar energy is absorbed), thus more energy added to the Earth. A new ice age in Norther Europe might slightly increase that area's albido, which would increase solar radiation and in theory mitigate global warming. But truth is, the effect of that change in albido will be very small compared to the effect of the atmospheric CO2 (which traps the solar radiation). Europe may be colder, but somewhere else is going to be much, much hotter.
- joshuaheard 3y ago
  You would think that adding that much ice in the atmosphere would cool it down a little, like putting an ice cube in a glass of water.
  - dotancohen 3y ago
    Where do you think that the "cold" in the ice comes from? It's just moving heat from one part of the planet to another. The total amount of heat entering the Earth is increasing, cold spots not withstanding.

chiefalchemist 3y ago

Since you're familiar with this stuff, and I didn't see it in the article, what's the impact if it were to collapse? To the ecology? To the weather? To other ocean currents?

GeoAtreides 3y ago

[flagged]

PKop 3y ago
You'd love to ruin his career and publicly shame him for having incorrect views wouldn't you? Awarding credibility on the basis of having a public face is absurd, and it's trivial to conceive of the way that could be politically silencing of dissident views, or that lack of anonymity would incentivize sticking to consensus. People disagree anonymously on the internet all the time, since the beginning. Are you incapable of judging the merits of an argument without requiring some appeal to authority?
- tarsinge 3y ago
  What is there to judge? The original commenter is the one making an appeal to authority, then just saying they are skeptical. In short an anonymous giving their opinion. The parent is right saying it’s of way lower value than the study.
  - PKop 3y ago
    Because a study lays out a more thorough and detailed argument, not because someone's real name or credentials are attached. The crux of my disagreement was his claim a name attached to an argument a priori makes it more valid than one that is anonymous. In a highly politicized environment, it can possibly be argue that a real name makes it less credible and more likely to be consensus. Putting that aside, it certainly doesn't it make it more credible.
oceanthrowaway 3y ago
I’m maybe overly cautious about my online footprint. I understand your skepticism and think it’s well placed. For what it’s worth I don’t see my comment as FUD and would wager that the authors of the study would agree with my comment. I enjoyed their study and was just trying to provide additional context (see also the link in my edit). You are totally right that my comment is worth significantly less than a peer reviewed study.