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That would mean severe impacts on the global climate, with Europe bearing the brunt of the impacts.
advertisementScientists have successfully modeled a climate tipping point where much of Europe would fall under polar ice, but that tipping point may be closer than previously thought.
Researchers at Utrecht University in the Netherlands used a complex climate model to simulate the disruption of the key Atlantic Current, which currently brings warm water north and keeps Europe’s temperatures moderate.
If these ocean currents suddenly stopped, the weather would change around the world, with Europe being the most severely affected. Melting ice sheets can cause collapse, but when and how likely will it occur?
What is the Atlantic circulation?
The Atlantic Meridional Circulation (AMOC) is an important ocean current system.it transports hot watercarbon and nutrients flow north through the Atlantic Ocean, where the water cools and sinks deeper.
AMOC helps distribute energy across the planet, moving heat through the oceans like a conveyor belt and regulating the climate.
Warmer water, made saltier by evaporation, flows northward across the ocean, keeping Europe calmer than other regions. When this water cools, it sinks because it becomes more salty and denser. It then returns to the southern hemisphere along the ocean floor.
However, studies of past episodes of dramatic cooling in Europe over the past 100,000 years have shown that melting ice sheet Changes in salinity and temperature can weaken the AMOC.
Fresh water reduces the salinity of the sea surface and therefore reduces the density of water. This means that surface water may sink less and ocean currents may flow more slowly.
Are we headed for a catastrophic tipping point?
Some studies suggest that climate change may be slowing the flow of ocean currents. A 2023 study based on sea surface temperatures suggests a complete collapse could occur between 2025 and 2095.
There is great uncertainty about when, how, or if this ‘tipping point’ will actually occur, making scenarios difficult to model. Most previous computer simulations showing collapse required adding unrealistically large amounts of fresh water all at once.
The Dutch team used supercomputers to perform the most sophisticated modeling ever to look for warning signs of this tipping point. By gradually adding water, they discovered that a gradual decline could eventually lead to a sudden collapse within 100 years.
Until now, the AMOC tipping point had been only a “theoretical concept,” the paper said, and the authors said that in their modeling, the speed at which this important current switch occurred was “remarkable.”
But the researchers had to run the simulation for more than 2,000 years to get this result, and as the Greenland ice sheet melted, it added significantly more water than is currently flowing into the ocean.
René van Westen, the study’s lead author, said there is currently not enough data to say anything conclusive about the likelihood of a future AMOC collapse. Further research is needed to establish a time period, including models that take into account increasing levels of carbon dioxide. global warming.
“All we can say is that we are heading towards a tipping point and that there is a possibility of a turnaround for AMOC.”
But some of the changes seen in the pre-collapse model are consistent with changes seen in the Atlantic Ocean in recent decades.
“As we can see from the available restructurings, if AMOC loses its stability, an abrupt transition in the future is likely,” Van Westen added.
What does the collapse of ocean currents mean for Europe?
Previous studies have shown that if the AMOC were to collapse, the resulting climate impacts would be nearly irreversible on human timescales. That would mean severe impacts on the global climate, with Europe bearing the brunt of the impacts.
advertisementTemperatures could drop by up to 30 degrees in some parts of Europe. On average, the model shows that London will be 10°C colder and Bergen 15°C colder.
The report’s authors said: “There are no realistic adaptation strategies that can cope with such rapid temperature changes.”
In the Southern Hemisphere, temperatures are expected to increase with the rainy and dry seasons. amazon rainforest To turn over.
Van Westen also noted that rainfall has decreased and sea level rise In coastal areas of Europe it reaches up to 1 meter.
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