The Gulf Stream
New alarm: AMOC may collapse in the 30s
Dutch researchers test new model: Really worrying
Christina Nordh
Published 14.25
Scientists' alarm about the collapse of the Gulf Stream is nothing new.
But according to a new study, it may happen sooner than we think.
Already in the 2030s.
The frightening conclusion about the AMOC, Atlantic meridional overturning circulation, is drawn in a new report.
Research indicates that the AMOC, due to warmer ocean temperatures and changing ocean salts due to human influence, will greatly slow down – or completely collapse, writes CNN.
Would lead to disaster
It would trigger a catastrophe over large parts of the earth and completely change the weather and climate, the researchers write in the report.
According to the model that the researchers used, the collapse can occur sometime between 2037 and 2064. The most likely year is 2050, according to the researchers.
- This is really worrying. All the negative side effects of anthropogenic (human-caused, ed. note) climate change will continue, such as more heat waves, more droughts, more floods, says René van Westen, study co-author and marine and atmospheric scientist at Utrecht University in the Netherlands.
- If you also add the collapse of the Gulf Stream ... the climate will change even more.
Like a conveyor belt, the AMOC pulls warm surface water from the southern hemosphere and the tropics and brings it to the cold waters of the North Atlantic. The cooler saline water sinks and then flows south. It cools parts of the southern hemisphere and at the same time ensures that parts of the north do not become unbearably cold - in addition, the current transports nutrients that keep marine ecosystems alive, writes CNN.
Growing ice sheet
In the event of a possible future collapse of the Gulf Stream, the Arctic ice will grow southward for several decades. After a hundred years, it would stretch all the way down to the south coast of England, according to the researchers.
Europe's average temperature would plummet, as would North America's including parts of the US. In the Amazon rainforest, the seasons would be turned upside down, today's dry periods would instead become rainy periods and vice versa.
- An AMOC collapse is a really big danger that we should do everything to avoid, says Stefan Rahmstorf, physical oceanographer at Potsdam University in Germany.
However, he did not participate in the new study.
New model
The Utrecht researchers used a new, modern type of model to produce their results. And for the first time, an area in the South Atlantic has been identified as the optimal location to measure change in the currents. They studied temperatures and salinity in the area to confirm earlier forecasts of when the Gulf Stream might reach its tipping point. Also atmospheric and land data.
- Until a few years ago, we discussed whether the Gulf Stream would collapse at all. Now it looks much more likely than just a few years ago that this will happen, says Rahmstorf.
May underestimate the risks
Around five years ago, he himself would have believed that the collapse of the Gulf Stream in this century was not likely, even if a ten percent risk is unacceptably high, he says.
- Now there are five reports that state that it may very well happen this century, even before the middle of the century. My overall assessment now is that the risk of us passing the tipping point this century is probably higher than 50 percent, says Rahmstorf to CNN.
However, the new model does not take into account melting ice from Greenland that flows out as fresh water into the North Atlantic and upsets the salinity.
- You get a huge influx of fresh water in the North Atlantic and it will completely disrupt the ecosystem. This weakness in the research means that forecasts of how soon or quickly a collapse can occur are underestimated, he says.
Meets Swedish criticism
The study's conclusions have been criticized by Swedish researchers.
- To hastily draw conclusions based on isolated observations, indirect reconstructions or model simulations is not only risky, it is downright misleading, Léon Chafik, oceanographer and climate scientist at Stockholm University, previously told SVT Nyheter.
His and his colleagues' research instead shows that the Nordic part of the Gulf Stream can be strengthened in a warmer world.
- It may indicate a potential resilience of the Gulf Stream that has not been noticed before, he tells the channel.
Footnote: The new research is currently being reviewed by experts in the field and has therefore not yet been published in any scientific journal.
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