5 ms·

> Predictions based on observations rely on detecting early-warning signals, primarily an increase in variance (loss of resilience) and increased autocorrelatio

by notamy 3y ago

> Predictions based on observations rely on detecting early-warning signals, primarily an increase in variance (loss of resilience) and increased autocorrelation (critical slowing down), which have recently been reported for the AMOC. Here we provide statistical significance and data-driven estimators for the time of tipping. We estimate a collapse of the AMOC to occur around mid-century under the current scenario of future emissions. The abstract also says that the collapse would impact the north Atlantic region, but in what way? Assuming the prediction is accurate, what changes could we expect to see in that scenario? Wikipedia suggests that temperatures in northern Europe would drop significantly + sea levels would rise, but is that all? https://en.wikipedia.org/wiki/Atlantic_meridional_overturning_circulation https://en.wikipedia.org/wiki/Atlantic_meridional_overturnin...

coremoff 3y ago
If nothing else, the UK would more closely resemble central Europe, as I understand it - colder winters, hotter summers
- richardwhiuk 3y ago
  Given a full collapse, wouldn't the UK resemble northern Canada?
  - pvaldes 3y ago
    There is a good way to see the problem in a second Think about New York, is at 40 degrees N latitude. This means that if NY would be in the Atlantic coast of Europe would fall in Portugal! a little North to Lisbon! (38ºN). Sometimes Is easy to forget that NY is "Southern Europe" league. Southern than the North Coast of Spain. Now lets see Quebec (53ºN). Well, London is 51ºN. Without the sea current bringing hot tropical water, London should have practically the same climate than Quebec, and 90% of UK is higher than London, so would enjoy the full whole Canadian winter experience.
    - deleted 3y ago
      [deleted]
    - hathchip 3y ago
      But the West Coast of North America is has milder winters than the East Coast, which has milder winters than the center. Shouldn't we expect London to end up with a similar climate as somewhere on the West Coast of Canada at the same latitude?
      - pvaldes 3y ago
        Probably Yes, because NY is also warmer that it should be. It receives still part of this warm water before the current turns toward east, plus it has also a heath-island effect created by cars and houses. So if you remove this effect for both Europe and US, NY should be much colder than it is currently (And most of Europe also).
      - saltcured 3y ago
        I think the hard part of this is predicting how the global jet stream and polar vortex winds might change in response to disruption of the Atlantic currents. It already changes for North America in response to the Pacific subtle temperature oscillation we call El Nino / La Nina. The proximity to the ocean and the general westerly winds of the mid latitudes mean that the west coast gets a moderating marine influence. The cold ocean surface provides us "air conditioning" in summer and yet is also a mild "heater" in winter, helping keep coastal air above freezing temperatures. But, this general background pattern is regularly disrupted by large high and low pressure systems that wander through the region and give us our weather of storms, cold snaps, and heat waves. These cyclonic systems can both carry a somewhat distinct air mass inside them and also disrupt the normal westerly surface flow. And the jet stream is largely in control of steering these systems, making them track further north or south or even helping them stall out temporarily in their generally eastward course.
      - beedeebeedee 3y ago
        > Shouldn't we expect ... similar climate as ... West Coast of Canada at same latitude The Pacific ocean has a similar current to the Gulf stream (AMOC) called the Kuroshio current. If the Gulf stream stops, you should expect the climate in London to be worse than the climate in the center of northern Canada.
  - dathinab 3y ago
    you can't really do comparisons like that as there are other currents which overlap with the overturning one and they won't stop even if that one stops due to them getting a lot of their energy from earth rotation. Through depending on which you look at they might become a bit hotter/colder. Also geography making it more, or less, likely for constant wind from the inland affecting the wetter can also affect the normal expected wetter noticeable. E.g. UK being a island means there are much less affected by inland wetter moving over to them then many typical Canadian comparison places. (And from-inland wind is the main cause of very hot summer or very cold winter wetter in many places e.g. cold weeks in north Germany, or e.g. the main source of Blizzards in the US). So IMHO comparisons like "this city is on the same latitude and also on the cost so it will have similar weather" without the overturning current are pointless (which doesn't mean that they can't happen to be correct, but they as much can happen to be fully wrong).
- juujian 3y ago
  I wonder if it would also mean that South America gets hotter, since that stream was carrying heat from SA to Europe
troupo 3y ago
> Wikipedia suggests that temperatures in northern Europe would drop significantly + sea levels would rise, but is that all? Depends on the drop and the rise. Open a world map, and draw parallels passing where large Northern European cities are. [1] E.g. Canada's Montreal roughly corresponds to Paris. [1] Or this gif from reddit: https://preview.redd.it/dm7xwsmp3aa81.gif?format=mp4&s=a16738d03fdcbbbf1373621cab50d55d178fb7c3 https://preview.redd.it/dm7xwsmp3aa81.gif?format=mp4&s=a1673...
snowwrestler 3y ago
Ireland and Great Britain are at about the same latitude as Labrador in Canada, but benefit from heat transported across the North Atlantic from the Caribbean by warm water. Absent the current that is transporting that warm water, one would expect the GB climate to more closely resemble Labrador’s. In other words, much colder.
- fmstack 3y ago
  not gonna lie, a scenario where a big nasty effect of climate change pastes Europe first might make the powers that be wake up to the impending disaster faster. For the folks with the big money one death in Europe might be more shocking than 100 deaths in India.
  - RandomLensman 3y ago
    If Europe expends much more energy to deal with cold and food production in the cold not sure that would help the world much.
  - IKantRead 3y ago
    The trouble with climate change has always been that by the time you notice the "big nasty effect" it's already too late to prevent catastrophe. To be clear, it's never too late to improve our fate, but by the time something like the AMOC shutting down destroys Europes climate, you've already signed up for an incredible amount of climate pain. Maybe such an event will wake us up enough to prevent out right extinction, but if this happened the collapse of industrial civilization would be virtually guaranteed.
    - kinjba11 3y ago
      Isn't that what this and other papers say - that AMOC is doomed to collapse, it's just a matter of time? I'm not sure I'd equate AMOC collapse to industrial civilization collapsing. My understanding with climate change is that we have signed up for a lot already, but much more is on the way if we don't make big changes faster. Humanity is a crisis-motivated species. The trouble with climate change is the effects so far have nearly no impact on power. If AMOC were to shut down in 2030 devastating Europe's economy, that could be the wake-up call to everyone to actually stop fossil-burning ourselves to doom for short-term conveniences.

by notamy 3y ago

coremoff 3y ago

If nothing else, the UK would more closely resemble central Europe, as I understand it - colder winters, hotter summers

richardwhiuk 3y ago
Given a full collapse, wouldn't the UK resemble northern Canada?
- pvaldes 3y ago
  There is a good way to see the problem in a second Think about New York, is at 40 degrees N latitude. This means that if NY would be in the Atlantic coast of Europe would fall in Portugal! a little North to Lisbon! (38ºN). Sometimes Is easy to forget that NY is "Southern Europe" league. Southern than the North Coast of Spain. Now lets see Quebec (53ºN). Well, London is 51ºN. Without the sea current bringing hot tropical water, London should have practically the same climate than Quebec, and 90% of UK is higher than London, so would enjoy the full whole Canadian winter experience.
  - deleted 3y ago
    [deleted]
  - hathchip 3y ago
    But the West Coast of North America is has milder winters than the East Coast, which has milder winters than the center. Shouldn't we expect London to end up with a similar climate as somewhere on the West Coast of Canada at the same latitude?
    - pvaldes 3y ago
      Probably Yes, because NY is also warmer that it should be. It receives still part of this warm water before the current turns toward east, plus it has also a heath-island effect created by cars and houses. So if you remove this effect for both Europe and US, NY should be much colder than it is currently (And most of Europe also).
    - saltcured 3y ago
      I think the hard part of this is predicting how the global jet stream and polar vortex winds might change in response to disruption of the Atlantic currents. It already changes for North America in response to the Pacific subtle temperature oscillation we call El Nino / La Nina. The proximity to the ocean and the general westerly winds of the mid latitudes mean that the west coast gets a moderating marine influence. The cold ocean surface provides us "air conditioning" in summer and yet is also a mild "heater" in winter, helping keep coastal air above freezing temperatures. But, this general background pattern is regularly disrupted by large high and low pressure systems that wander through the region and give us our weather of storms, cold snaps, and heat waves. These cyclonic systems can both carry a somewhat distinct air mass inside them and also disrupt the normal westerly surface flow. And the jet stream is largely in control of steering these systems, making them track further north or south or even helping them stall out temporarily in their generally eastward course.
    - beedeebeedee 3y ago
      > Shouldn't we expect ... similar climate as ... West Coast of Canada at same latitude The Pacific ocean has a similar current to the Gulf stream (AMOC) called the Kuroshio current. If the Gulf stream stops, you should expect the climate in London to be worse than the climate in the center of northern Canada.
- dathinab 3y ago
  you can't really do comparisons like that as there are other currents which overlap with the overturning one and they won't stop even if that one stops due to them getting a lot of their energy from earth rotation. Through depending on which you look at they might become a bit hotter/colder. Also geography making it more, or less, likely for constant wind from the inland affecting the wetter can also affect the normal expected wetter noticeable. E.g. UK being a island means there are much less affected by inland wetter moving over to them then many typical Canadian comparison places. (And from-inland wind is the main cause of very hot summer or very cold winter wetter in many places e.g. cold weeks in north Germany, or e.g. the main source of Blizzards in the US). So IMHO comparisons like "this city is on the same latitude and also on the cost so it will have similar weather" without the overturning current are pointless (which doesn't mean that they can't happen to be correct, but they as much can happen to be fully wrong).
juujian 3y ago
I wonder if it would also mean that South America gets hotter, since that stream was carrying heat from SA to Europe

troupo 3y ago

> Wikipedia suggests that temperatures in northern Europe would drop significantly + sea levels would rise, but is that all? Depends on the drop and the rise. Open a world map, and draw parallels passing where large Northern European cities are. [1] E.g. Canada's Montreal roughly corresponds to Paris. [1] Or this gif from reddit: https://preview.redd.it/dm7xwsmp3aa81.gif?format=mp4&s=a16738d03fdcbbbf1373621cab50d55d178fb7c3 https://preview.redd.it/dm7xwsmp3aa81.gif?format=mp4&s=a1673...

snowwrestler 3y ago

Ireland and Great Britain are at about the same latitude as Labrador in Canada, but benefit from heat transported across the North Atlantic from the Caribbean by warm water. Absent the current that is transporting that warm water, one would expect the GB climate to more closely resemble Labrador’s. In other words, much colder.

fmstack 3y ago
not gonna lie, a scenario where a big nasty effect of climate change pastes Europe first might make the powers that be wake up to the impending disaster faster. For the folks with the big money one death in Europe might be more shocking than 100 deaths in India.
- RandomLensman 3y ago
  If Europe expends much more energy to deal with cold and food production in the cold not sure that would help the world much.
- IKantRead 3y ago
  The trouble with climate change has always been that by the time you notice the "big nasty effect" it's already too late to prevent catastrophe. To be clear, it's never too late to improve our fate, but by the time something like the AMOC shutting down destroys Europes climate, you've already signed up for an incredible amount of climate pain. Maybe such an event will wake us up enough to prevent out right extinction, but if this happened the collapse of industrial civilization would be virtually guaranteed.
  - kinjba11 3y ago
    Isn't that what this and other papers say - that AMOC is doomed to collapse, it's just a matter of time? I'm not sure I'd equate AMOC collapse to industrial civilization collapsing. My understanding with climate change is that we have signed up for a lot already, but much more is on the way if we don't make big changes faster. Humanity is a crisis-motivated species. The trouble with climate change is the effects so far have nearly no impact on power. If AMOC were to shut down in 2030 devastating Europe's economy, that could be the wake-up call to everyone to actually stop fossil-burning ourselves to doom for short-term conveniences.