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>If the AMOC collapsed, it would increase cooling of the Northern Hemisphere, sea level rise in the Atlantic, an overall fall in precipitation over Europe and N

>If the AMOC collapsed, it would increase cooling of the Northern Hemisphere, sea level rise in the Atlantic, an overall fall in precipitation over Europe and North America and a shift in monsoons in South America and Afria, Britain's Met Office said. Have the other major climate models accounted for this? Most I've seen have predicted rapid warming in North America. Not sure how to reconcile the difference. Perhaps the cooling effect is more concentrated over the oceans and coasts?

tuatoru 5y ago
North America is a minor fraction of the northern hemisphere. Yes, models have consistently predicted warming and drying of the western US at least since I was running climateprediction.net HadCM3 models (through BOINC) in the 00s: the return of the Great American Desert, basically everywhere west of the Mississippi and south of British Columbia. Secondly, the cooling is an average, and relative to the situation without collapse of the AMOC. In most places, it still gets hot; but in Northern Europe, not so much. It even cools relative to the situation in 1900, IIRC. And yes, you are right about the location. The visible part of the AMOC is called the Gulf Stream, and it's the reason London does not have the same climate as Labrador.
- Teknoman117 5y ago
  Maybe it's a bad idea to be currently thinking about buying a house in southern California. It's just so depressing. No one cares, no one is willing to do anything about it. All the politicians say that it'll get fixed at some point in the future (i.e. after their careers) so that their current donors don't get mad. You also have the people who see the evidence for a warming climate, and just say "well that still doesn't mean we humans have anything to do with it". Even if it was a completely natural process, the result is going to be bad for us. We should do something.
  - tuatoru 5y ago
    > We should do something. Oh, we (the global "we") will, eventually. It's just that the incentives for politicians are to let crises get bad before acting, so that people notice them and remember them. No-one (well hardly anyone) remembers people who stopped a catastrophe from happening in the first place. For example, Stanislav Petrov ought to have a statue in every town in the world.[1] But "who's he?" is what you get when you mention him. In the case of climate change, when the effects are bad enough for politicians to act, their actions will be draconian but ineffective. I can't offer any Disney ending to the story, but we must carry on anyway. It won't be the end of the world, just a much worse future than we might have had. 1. https://en.wikipedia.org/wiki/Stanislav_Petrov https://en.wikipedia.org/wiki/Stanislav_Petrov
    - ncr100 5y ago
      So - laws and regulations need changing. We have science and easily observable evidence to guide this change. Just need to do it now. Intransigent politicians will be out, and politicians who're in-step with the populace will be in. 2.5% improvement since last US Congress electoral cycle, of more politicians who acknowledge climate science. Climate deniers: https://www.americanprogress.org/issues/green/news/2021/03/30/497685/climate-deniers-117th-congress/ https://www.americanprogress.org/issues/green/news/2021/03/3... Still with 32% (139 of 435) denying climate science, we have a ways to go. Totals: https://www.govtrack.us/congress/members https://www.govtrack.us/congress/members
    - Kye 5y ago
      People still talk like the y2k bug was nothing because of all the hard work done to prepare for it.
  - tstrimple 5y ago
    > All the politicians say that it'll get fixed at some point in the future To be perfectly clear, there is exactly one political party in the United States who still doesn't even acknowledge anthropogenic climate change, never mind taking any steps to change things. It's incredibly frustrating that this too gets framed as a "both sides" issue despite all evidence indicating it's a one sided issue.
    - creamytaco 5y ago
      This is short sighted since political parties are both playing for the same team: they are owned by finance and corporations. These are entities that are absolutely not going to allow the radical changes needed to stay within 2c temperature gain (which is still bad, millions will die, but maybe not catastrophic for the species as a whole). Alas, 2c is already priced in given current policies, we will be lucky to stay below 3c. The societal changes from that alone will be devastating.
  - madaxe_again 5y ago
    Me, I’d given up on we, so I do what I can. I moved off grid two years ago, bought 5ha of abandoned farmland, now more like 30ha, and am rewilding it - transplanted lots of saplings, encouraged wildlife, and within two years we’ve gone from fire-risk scrub to a young ash and oak forest, which is already providing cover for third succession species. We had a fire from a cigarette by a road last week, and it just stopped at the edge of the forest. Green undergrowth doesn’t burn very well. Long dry springs have started running. Local farmers are taking notice - we’ve had people coming by and turning green with envy at our running water, in August. There was nothing on this land - just a few hopeful looking dips that looked like old water courses. Other people are now planting up around their old springs, which they all bulldozed bare decades ago when they got pumped irrigation from the river - which now runs dry from June - Sept every year, as all the water is pumped out to evaporate on the bare earth of the highlands. Hunting is a huge part of the lifestyle here, and it’s done pretty sustainably - I’ve been really enheartened talking to people here about the importance of large wildlife to the ecosystem. Local hunt have agreed to have a two year moratorium on boar hunting near us, so we can collect data on population and the impact of their activities - our hope is that by providing habitat for them they stop being an agricultural pest, and their numbers can rebound to the point where their population is stable, and able to support apex predators - wolves. Normal, rural folk are seeing the devastation the changing climate is bringing (fires, floods, fires, floods), and there’s a genuine desire to do something. Our energy is all renewable, apart from a few weeks in the winter when we run the generator (although that goes next year - new hydro turbine on order). We don’t fly any more - covid made that decision really easy - all travel is overland. Sure, takes longer - and gives you so much more to see. I can’t stop global climate change, but I can at least stop being part of the problem - and if enough people take that step, then maybe there’s hope for “we”.
    - geedy 5y ago
      Thank you for your amazing work! :)
      - madaxe_again 5y ago
        Honestly, I do this for me, and I feel I have a lot to make up for.
laurent92 5y ago
The slowing of the Gulf Stream, at least, which keeps Europe warm despite cooler temperatures at the same latitude in Canada, has always been one of the discussed scenarios. I don’t know whether IPCC made models, though.

tuatoru 5y ago

North America is a minor fraction of the northern hemisphere. Yes, models have consistently predicted warming and drying of the western US at least since I was running climateprediction.net HadCM3 models (through BOINC) in the 00s: the return of the Great American Desert, basically everywhere west of the Mississippi and south of British Columbia. Secondly, the cooling is an average, and relative to the situation without collapse of the AMOC. In most places, it still gets hot; but in Northern Europe, not so much. It even cools relative to the situation in 1900, IIRC. And yes, you are right about the location. The visible part of the AMOC is called the Gulf Stream, and it's the reason London does not have the same climate as Labrador.

Teknoman117 5y ago
Maybe it's a bad idea to be currently thinking about buying a house in southern California. It's just so depressing. No one cares, no one is willing to do anything about it. All the politicians say that it'll get fixed at some point in the future (i.e. after their careers) so that their current donors don't get mad. You also have the people who see the evidence for a warming climate, and just say "well that still doesn't mean we humans have anything to do with it". Even if it was a completely natural process, the result is going to be bad for us. We should do something.
- tuatoru 5y ago
  > We should do something. Oh, we (the global "we") will, eventually. It's just that the incentives for politicians are to let crises get bad before acting, so that people notice them and remember them. No-one (well hardly anyone) remembers people who stopped a catastrophe from happening in the first place. For example, Stanislav Petrov ought to have a statue in every town in the world.[1] But "who's he?" is what you get when you mention him. In the case of climate change, when the effects are bad enough for politicians to act, their actions will be draconian but ineffective. I can't offer any Disney ending to the story, but we must carry on anyway. It won't be the end of the world, just a much worse future than we might have had. 1. https://en.wikipedia.org/wiki/Stanislav_Petrov https://en.wikipedia.org/wiki/Stanislav_Petrov
  - ncr100 5y ago
    So - laws and regulations need changing. We have science and easily observable evidence to guide this change. Just need to do it now. Intransigent politicians will be out, and politicians who're in-step with the populace will be in. 2.5% improvement since last US Congress electoral cycle, of more politicians who acknowledge climate science. Climate deniers: https://www.americanprogress.org/issues/green/news/2021/03/30/497685/climate-deniers-117th-congress/ https://www.americanprogress.org/issues/green/news/2021/03/3... Still with 32% (139 of 435) denying climate science, we have a ways to go. Totals: https://www.govtrack.us/congress/members https://www.govtrack.us/congress/members
  - Kye 5y ago
    People still talk like the y2k bug was nothing because of all the hard work done to prepare for it.
- tstrimple 5y ago
  > All the politicians say that it'll get fixed at some point in the future To be perfectly clear, there is exactly one political party in the United States who still doesn't even acknowledge anthropogenic climate change, never mind taking any steps to change things. It's incredibly frustrating that this too gets framed as a "both sides" issue despite all evidence indicating it's a one sided issue.
  - creamytaco 5y ago
    This is short sighted since political parties are both playing for the same team: they are owned by finance and corporations. These are entities that are absolutely not going to allow the radical changes needed to stay within 2c temperature gain (which is still bad, millions will die, but maybe not catastrophic for the species as a whole). Alas, 2c is already priced in given current policies, we will be lucky to stay below 3c. The societal changes from that alone will be devastating.
- madaxe_again 5y ago
  Me, I’d given up on we, so I do what I can. I moved off grid two years ago, bought 5ha of abandoned farmland, now more like 30ha, and am rewilding it - transplanted lots of saplings, encouraged wildlife, and within two years we’ve gone from fire-risk scrub to a young ash and oak forest, which is already providing cover for third succession species. We had a fire from a cigarette by a road last week, and it just stopped at the edge of the forest. Green undergrowth doesn’t burn very well. Long dry springs have started running. Local farmers are taking notice - we’ve had people coming by and turning green with envy at our running water, in August. There was nothing on this land - just a few hopeful looking dips that looked like old water courses. Other people are now planting up around their old springs, which they all bulldozed bare decades ago when they got pumped irrigation from the river - which now runs dry from June - Sept every year, as all the water is pumped out to evaporate on the bare earth of the highlands. Hunting is a huge part of the lifestyle here, and it’s done pretty sustainably - I’ve been really enheartened talking to people here about the importance of large wildlife to the ecosystem. Local hunt have agreed to have a two year moratorium on boar hunting near us, so we can collect data on population and the impact of their activities - our hope is that by providing habitat for them they stop being an agricultural pest, and their numbers can rebound to the point where their population is stable, and able to support apex predators - wolves. Normal, rural folk are seeing the devastation the changing climate is bringing (fires, floods, fires, floods), and there’s a genuine desire to do something. Our energy is all renewable, apart from a few weeks in the winter when we run the generator (although that goes next year - new hydro turbine on order). We don’t fly any more - covid made that decision really easy - all travel is overland. Sure, takes longer - and gives you so much more to see. I can’t stop global climate change, but I can at least stop being part of the problem - and if enough people take that step, then maybe there’s hope for “we”.
  - geedy 5y ago
    Thank you for your amazing work! :)
    - madaxe_again 5y ago
      Honestly, I do this for me, and I feel I have a lot to make up for.

laurent92 5y ago

The slowing of the Gulf Stream, at least, which keeps Europe warm despite cooler temperatures at the same latitude in Canada, has always been one of the discussed scenarios. I don’t know whether IPCC made models, though.