NPR

The Gulf Stream system could collapse as soon as 2025, a new study suggests. The shutting down of the vital ocean currents, called the Atlantic Meridional Overturning Circulation (Amoc) by scientists, would bring catastrophic climate impacts.

Amoc was already known to be at its weakest in 1,600 years owing to global heating and researchers spotted warning signs of a tipping point in 2021.

The new analysis estimates a timescale for the collapse of between 2025 and 2095, with a central estimate of 2050, if global carbon emissions are not reduced. Evidence from past collapses indicate changes of temperature of 10C in a few decades, although these occurred during ice ages.

Other scientists said the assumptions about how a tipping point would play out and uncertainties in the underlying data are too large for a reliable estimate of the timing of the tipping point. But all said the prospect of an Amoc collapse was extremely concerning and should spur rapid cuts in carbon emissions.

Amoc carries warm ocean water northwards towards the pole where it cools and sinks, driving the Atlantic’s currents. But an influx of fresh water from the accelerating melting of Greenland’s ice cap and other sources is increasingly smothering the currents.

A collapse of Amoc would have disastrous consequences around the world, severely disrupting the rains that billions of people depend on for food in India, South America and west Africa. It would increase storms and drop temperatures in Europe, and lead to a rising sea level on the eastern coast of North America. It would also further endanger the Amazon rainforest and Antarctic ice sheets.

“I think we should be very worried,” said Prof Peter Ditlevsen, at the University of Copenhagen in Denmark, and who led the new study. “This would be a very, very large change. The Amoc has not been shut off for 12,000 years.”


The Amoc collapsed and restarted repeatedly in the cycle of ice ages that occurred from 115,000 to 12,000 years ago. It is one of the climate tipping points scientists are most concerned about as global temperatures continue to rise.

Research in 2022 showed five dangerous tipping points may already have been passed due to the 1.1C of global heating to date, including the shutdown of Amoc, the collapse of Greenland’s ice cap and an abrupt melting of carbon-rich permafrost.

The new study, published in the journal Nature Communications, used sea surface temperature data stretching back to 1870 as a proxy for the change in strength of Amoc currents over time.

The researchers then mapped this data on to the path seen in systems that are approaching a particular type of tipping point called a “saddle-node bifurcation”. The data fitted “surprisingly well”, Ditlevsen said. The researchers were then able to extrapolate the data to estimate when the tipping point was likely to occur. Further statistical analysis provided a measure of the uncertainty in the estimate.


The analysis is based on greenhouse gas emissions rising as they have done to date. If emissions do start to fall, as intended by current climate policies, then the world would have more time to try to keep global temperature below the Amoc tipping point.

The most recent assessment by the Intergovernmental Panel on Climate Change concluded that Amoc would not collapse this century. But Divlitsen said the models used have coarse resolution and are not adept at analysing the non-linear processes involved, which may make them overly conservative.

The potential collapse of Amoc is intensely debated by scientists, who have previously said it must be avoided “at all costs”.

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Prof Niklas Boers, from the Potsdam Institute for Climate Impact Research in Germany, revealed the early warning signs of Amoc collapse in 2021. “The results of the new study sound alarming but if the uncertainties in the heavily oversimplified model [of the tipping point] and in the underlying [sea temperature] data are included, then it becomes clear that these uncertainties are too large to make any reliable estimate of the time of tipping.”


Prof David Thornalley, at University College London, UK, agreed the study had large caveats and unknowns and said further research was essential: “But if the statistics are robust and a relevant way to describe how the actual Amoc behaves, then this is a very concerning result.”

Dr Levke Caesar, at the University of Bremen, Germany, said using sea surface temperatures as proxy data for the strength of the Amoc currents was a key source of uncertainty: “We only have direct observational data of the Amoc since 2004.”

The extrapolation in the new analysis was reasonable, according to Prof Tim Lenton, at the University of Exeter, UK. He said the tipping point could lead to a partial Amoc collapse, for example only in the Labrador Sea, but that this would still cause major impacts. Divlitsen said he hoped the debate would drive new research: “It’s always fruitful when you do not exactly agree.”

Prof Stefan Rahmstorf, at the University of Potsdam, Germany, said: “There is still large uncertainty where the Amoc tipping point is, but the new study adds to the evidence that it is much closer than we thought. A single study provides limited evidence, but when multiple approaches have led to similar conclusions this must be taken very seriously, especially when we’re talking about a risk that we really want to rule out with 99.9% certainty. Now we can’t even rule out crossing the tipping point in the next decade or two.”

lemonhead wrote: ↑Tue Jul 25, 2023 8:07 pm Maybe the Med countries spontaneously combusting this summer will jog a few memories.

Uncle fester wrote: ↑Tue Jul 25, 2023 7:03 pm https://www.theguardian.com/environment ... y-suggests

The Gulf Stream system could collapse as soon as 2025, a new study suggests. The shutting down of the vital ocean currents, called the Atlantic Meridional Overturning Circulation (Amoc) by scientists, would bring catastrophic climate impacts.

Amoc was already known to be at its weakest in 1,600 years owing to global heating and researchers spotted warning signs of a tipping point in 2021.

The new analysis estimates a timescale for the collapse of between 2025 and 2095, with a central estimate of 2050, if global carbon emissions are not reduced. Evidence from past collapses indicate changes of temperature of 10C in a few decades, although these occurred during ice ages.

Other scientists said the assumptions about how a tipping point would play out and uncertainties in the underlying data are too large for a reliable estimate of the timing of the tipping point. But all said the prospect of an Amoc collapse was extremely concerning and should spur rapid cuts in carbon emissions.

Amoc carries warm ocean water northwards towards the pole where it cools and sinks, driving the Atlantic’s currents. But an influx of fresh water from the accelerating melting of Greenland’s ice cap and other sources is increasingly smothering the currents.

A collapse of Amoc would have disastrous consequences around the world, severely disrupting the rains that billions of people depend on for food in India, South America and west Africa. It would increase storms and drop temperatures in Europe, and lead to a rising sea level on the eastern coast of North America. It would also further endanger the Amazon rainforest and Antarctic ice sheets.

“I think we should be very worried,” said Prof Peter Ditlevsen, at the University of Copenhagen in Denmark, and who led the new study. “This would be a very, very large change. The Amoc has not been shut off for 12,000 years.”


The Amoc collapsed and restarted repeatedly in the cycle of ice ages that occurred from 115,000 to 12,000 years ago. It is one of the climate tipping points scientists are most concerned about as global temperatures continue to rise.

Research in 2022 showed five dangerous tipping points may already have been passed due to the 1.1C of global heating to date, including the shutdown of Amoc, the collapse of Greenland’s ice cap and an abrupt melting of carbon-rich permafrost.

The new study, published in the journal Nature Communications, used sea surface temperature data stretching back to 1870 as a proxy for the change in strength of Amoc currents over time.

The researchers then mapped this data on to the path seen in systems that are approaching a particular type of tipping point called a “saddle-node bifurcation”. The data fitted “surprisingly well”, Ditlevsen said. The researchers were then able to extrapolate the data to estimate when the tipping point was likely to occur. Further statistical analysis provided a measure of the uncertainty in the estimate.


The analysis is based on greenhouse gas emissions rising as they have done to date. If emissions do start to fall, as intended by current climate policies, then the world would have more time to try to keep global temperature below the Amoc tipping point.

The most recent assessment by the Intergovernmental Panel on Climate Change concluded that Amoc would not collapse this century. But Divlitsen said the models used have coarse resolution and are not adept at analysing the non-linear processes involved, which may make them overly conservative.

The potential collapse of Amoc is intensely debated by scientists, who have previously said it must be avoided “at all costs”.

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Prof Niklas Boers, from the Potsdam Institute for Climate Impact Research in Germany, revealed the early warning signs of Amoc collapse in 2021. “The results of the new study sound alarming but if the uncertainties in the heavily oversimplified model [of the tipping point] and in the underlying [sea temperature] data are included, then it becomes clear that these uncertainties are too large to make any reliable estimate of the time of tipping.”


Prof David Thornalley, at University College London, UK, agreed the study had large caveats and unknowns and said further research was essential: “But if the statistics are robust and a relevant way to describe how the actual Amoc behaves, then this is a very concerning result.”

Dr Levke Caesar, at the University of Bremen, Germany, said using sea surface temperatures as proxy data for the strength of the Amoc currents was a key source of uncertainty: “We only have direct observational data of the Amoc since 2004.”

The extrapolation in the new analysis was reasonable, according to Prof Tim Lenton, at the University of Exeter, UK. He said the tipping point could lead to a partial Amoc collapse, for example only in the Labrador Sea, but that this would still cause major impacts. Divlitsen said he hoped the debate would drive new research: “It’s always fruitful when you do not exactly agree.”

Prof Stefan Rahmstorf, at the University of Potsdam, Germany, said: “There is still large uncertainty where the Amoc tipping point is, but the new study adds to the evidence that it is much closer than we thought. A single study provides limited evidence, but when multiple approaches have led to similar conclusions this must be taken very seriously, especially when we’re talking about a risk that we really want to rule out with 99.9% certainty. Now we can’t even rule out crossing the tipping point in the next decade or two.”

Torquemada 1420 wrote: ↑Tue Jul 25, 2023 8:25 pm

lemonhead wrote: ↑Tue Jul 25, 2023 8:07 pm Maybe the Med countries spontaneously combusting this summer will jog a few memories.

Doubt it. Those burning aren't in charge.

Ymx wrote: ↑Tue Jul 25, 2023 8:34 pm When it does, what does it mean for temps on the island?

South East becomes Scotland, Scotland becomes Greenland?

Guy Smiley wrote: ↑Tue Jul 25, 2023 8:38 pm

Ymx wrote: ↑Tue Jul 25, 2023 8:34 pm When it does, what does it mean for temps on the island?

South East becomes Scotland, Scotland becomes Greenland?

Europe starts turning back boat people trying to escape the UK.

Ymx wrote: ↑Tue Jul 25, 2023 8:34 pm When it does, what does it mean for temps on the island?

South East becomes Scotland, Scotland becomes Greenland?

Guy Smiley wrote: ↑Tue Jul 25, 2023 8:33 pm

Torquemada 1420 wrote: ↑Tue Jul 25, 2023 8:25 pm

lemonhead wrote: ↑Tue Jul 25, 2023 8:07 pm Maybe the Med countries spontaneously combusting this summer will jog a few memories.

Doubt it. Those burning aren't in charge.

Temperature records being broken daily across multiple states including the USA, severe weather events across the world increasingly linked to ocean surface temperatures and we're entering an El Nino cycle....

I reckon it's going to be hard for them to ignore it within a few months. We have crossed a few scary tipping point indicators...including the Antarctic ice sheet thickness. If that lets go say goodbye to ocean front property everywhere.

Torquemada 1420 wrote: ↑Tue Jul 25, 2023 8:44 pm

Guy Smiley wrote: ↑Tue Jul 25, 2023 8:33 pm

Torquemada 1420 wrote: ↑Tue Jul 25, 2023 8:25 pm

Doubt it. Those burning aren't in charge.

Temperature records being broken daily across multiple states including the USA, severe weather events across the world increasingly linked to ocean surface temperatures and we're entering an El Nino cycle....

I reckon it's going to be hard for them to ignore it within a few months. We have crossed a few scary tipping point indicators...including the Antarctic ice sheet thickness. If that lets go say goodbye to ocean front property everywhere.

I wish I had your optimism in the ability of the masses to change the vast corporate and wealthy's interests in watching us all burn.

Things are quite a bit different if the AMOC shuts down. Rather than rising, temperatures would actually drop by an average of 3.4°C. That drop would occur on a gradient, with northern Scotland cooling the most and southern England seeing the least impact and therefore seeing conditions similar to what it currently experiences. But, more dramatically, rainfall during the growing season is expected to drop by 123mm. That drop is enough to reduce the UK's percentage of arable land from 32 percent to just seven percent. Obviously, this would cause a big hit to the UK's agricultural productivity. Irrigation could again offset this, but the scale of the changes needed would be far larger; the authors estimate adding this irrigation at ten times the value of the crops that would be produced. But they note that it's not clear if the UK would have enough water to spare to fully reverse the loss of rain.

Torquemada 1420 wrote: ↑Tue Jul 25, 2023 8:42 pm

Ymx wrote: ↑Tue Jul 25, 2023 8:34 pm When it does, what does it mean for temps on the island?

South East becomes Scotland, Scotland becomes Greenland?

Yes. Look at where the UK is in terms of latitude. The conveyor keeps the UK warm but if the caps melt, it will be headed off/cut off before it reaches the coast here.

Sandstorm wrote: ↑Tue Jul 25, 2023 7:25 pm So collapse in 2021. Wait. 2029. Or almost certainly in 2050.
Gotcha.

CM11 wrote: ↑Tue Jul 25, 2023 10:10 pm They've given a wide range and then said it can be arrested.

Biffer wrote: ↑Tue Jul 25, 2023 10:10 pm

Torquemada 1420 wrote: ↑Tue Jul 25, 2023 8:42 pm

Ymx wrote: ↑Tue Jul 25, 2023 8:34 pm When it does, what does it mean for temps on the island?

South East becomes Scotland, Scotland becomes Greenland?

Yes. Look at where the UK is in terms of latitude. The conveyor keeps the UK warm but if the caps melt, it will be headed off/cut off before it reaches the coast here.

Kind of. We'll be more influenced by continental weather patterns so colder in winter and warmer in summer. Less rain, so exacerbating the already critical water situation in the south of England.

boere wors wrote: ↑Wed Jul 26, 2023 7:00 am

Biffer wrote: ↑Tue Jul 25, 2023 10:10 pm

Torquemada 1420 wrote: ↑Tue Jul 25, 2023 8:42 pm

Yes. Look at where the UK is in terms of latitude. The conveyor keeps the UK warm but if the caps melt, it will be headed off/cut off before it reaches the coast here.

Kind of. We'll be more influenced by continental weather patterns so colder in winter and warmer in summer. Less rain, so exacerbating the already critical water situation in the south of England.

So is there any negative effect?!

Biffer wrote: ↑Wed Jul 26, 2023 7:41 am

boere wors wrote: ↑Wed Jul 26, 2023 7:00 am

Biffer wrote: ↑Tue Jul 25, 2023 10:10 pm

Kind of. We'll be more influenced by continental weather patterns so colder in winter and warmer in summer. Less rain, so exacerbating the already critical water situation in the south of England.

So is there any negative effect?!

Parts of England will be in permanent drought. London and the south east gets around the same annual rainfall as the Lebanon at the moment, less than Sydney. In an area with 18 million people.

Current infrastructure isn’t designed for those extremes.

Tichtheid wrote: ↑Wed Jul 26, 2023 8:09 am

Biffer wrote: ↑Wed Jul 26, 2023 7:41 am

boere wors wrote: ↑Wed Jul 26, 2023 7:00 am
So is there any negative effect?!

Parts of England will be in permanent drought. London and the south east gets around the same annual rainfall as the Lebanon at the moment, less than Sydney. In an area with 18 million people.

Current infrastructure isn’t designed for those extremes.

Do you happen to know what percentage of rainwater is currently collected across the UK? I seem to remember that it was an incredibly low number but I forget and a quick Google doesn't tell me much. Then there is waste due to leaks in a Victorian water infrastructure.

Desalination isn't really a credible answer at any scale because of the hyper-salinated water pumped back into the sea

Tichtheid wrote: ↑Wed Jul 26, 2023 8:09 am

Biffer wrote: ↑Wed Jul 26, 2023 7:41 am

boere wors wrote: ↑Wed Jul 26, 2023 7:00 am
So is there any negative effect?!

Parts of England will be in permanent drought. London and the south east gets around the same annual rainfall as the Lebanon at the moment, less than Sydney. In an area with 18 million people.

Current infrastructure isn’t designed for those extremes.

Do you happen to know what percentage of rainwater is currently collected across the UK? I seem to remember that it was an incredibly low number but I forget and a quick Google doesn't tell me much. Then there is waste due to leaks in a Victorian water infrastructure.

Desalination isn't really a credible answer at any scale because of the hyper-salinated water pumped back into the sea

Jim Lahey wrote: ↑Wed Jul 26, 2023 8:35 am And just as I was getting back into playing golf regularly ffs.
You are all a pack of carbon emitting selfish karnts.

Sandstorm wrote: ↑Wed Jul 26, 2023 8:44 am
Build dams people. In Wales. Generate power at the same time as catching rainfall & creating jobs. Simple. Except in UK apparently.

Guy Smiley wrote: ↑Wed Jul 26, 2023 8:46 am

Sandstorm wrote: ↑Wed Jul 26, 2023 8:44 am
Build dams people. In Wales. Generate power at the same time as catching rainfall & creating jobs. Simple. Except in UK apparently.

Which part of reduced rainfall did you struggle with?

Sandstorm wrote: ↑Wed Jul 26, 2023 8:45 am

Jim Lahey wrote: ↑Wed Jul 26, 2023 8:35 am And just as I was getting back into playing golf regularly ffs.
You are all a pack of carbon emitting selfish karnts.

Your steel irons and plastic balls are killing the planet!

Guy Smiley wrote: ↑Wed Jul 26, 2023 8:46 am

Sandstorm wrote: ↑Wed Jul 26, 2023 8:44 am
Build dams people. In Wales. Generate power at the same time as catching rainfall & creating jobs. Simple. Except in UK apparently.

Which part of reduced rainfall did you struggle with?

tc27 wrote: ↑Wed Jul 26, 2023 9:28 am Wow hopefully getting white vans owners in Uxbridge to pay a extra 4k a year will fix this

tc27 wrote: ↑Wed Jul 26, 2023 9:30 am

Guy Smiley wrote: ↑Wed Jul 26, 2023 8:46 am

Sandstorm wrote: ↑Wed Jul 26, 2023 8:44 am
Build dams people. In Wales. Generate power at the same time as catching rainfall & creating jobs. Simple. Except in UK apparently.

Which part of reduced rainfall did you struggle with?

The UK has absolutely an abundance of fresh water. The problem is building reservoirs may upset people so we dont

Sandstorm wrote: ↑Wed Jul 26, 2023 8:48 am

Guy Smiley wrote: ↑Wed Jul 26, 2023 8:46 am

Sandstorm wrote: ↑Wed Jul 26, 2023 8:44 am
Build dams people. In Wales. Generate power at the same time as catching rainfall & creating jobs. Simple. Except in UK apparently.

Which part of reduced rainfall did you struggle with?

Wales has 5 times the rainfall as Kent - the area where the drought is expected to be most severe. None is currently collected, it just runs into the sea.

Ymx wrote: ↑Wed Jul 26, 2023 9:59 am
Are we going to have to build stuff and then all move to Wales?? Oh fuck.

Sandstorm wrote: ↑Wed Jul 26, 2023 9:33 am

tc27 wrote: ↑Wed Jul 26, 2023 9:30 am

Guy Smiley wrote: ↑Wed Jul 26, 2023 8:46 am

Which part of reduced rainfall did you struggle with?

The UK has absolutely an abundance of fresh water. The problem is building reservoirs may upset people so we dont

It's a weird thing. A reservoir is probably the most attractive & least disruptive public works structure that you can possibly put into any landscape, but still there's massive resistance.

robmatic wrote: ↑Wed Jul 26, 2023 10:04 am

Sandstorm wrote: ↑Wed Jul 26, 2023 9:33 am

tc27 wrote: ↑Wed Jul 26, 2023 9:30 am

The UK has absolutely an abundance of fresh water. The problem is building reservoirs may upset people so we dont

It's a weird thing. A reservoir is probably the most attractive & least disruptive public works structure that you can possibly put into any landscape, but still there's massive resistance.

British Nimbyism is truly world-beating.

Sandstorm wrote: ↑Wed Jul 26, 2023 10:03 am

Ymx wrote: ↑Wed Jul 26, 2023 9:59 am
Are we going to have to build stuff and then all move to Wales?? Oh fuck.

You can have REFRY as a neighbour