There's a Chance the North Atlantic Current Will Shut Down Temporarily in the Next 100 Years

In the next 100 years, there is a 15 percent chance the North Atlantic Current could experience a temporary shutdown, scientists have said. The current brings warm water from the Gulf of Mexico towards Europe, helping keep the continent mild.

A hiatus to the current, researchers say, could cause temperatures in Europe and the Northern Hemisphere more generally to fall.

The ocean current, known as the Atlantic Meridional Overturning Circulation (AMOC) is an important part of Earth's climate system. It moves warm water from the upper layers of the Atlantic to the north, and colder waters deeper below the surface southwards. It is believed the AMOC has experienced several abrupt changes over time.

At the moment, AMOC appears to be weakening. Last year, researchers said it is currently at its weakest point in 1,500 years. Earlier this year, another team found the current started weakening about 400 years before a global cold snap 13,000 years ago. The same team also found that it got stronger about 400 years before a period of warming.

"Previous studies have shown that a shutdown of the AMOC would considerably affect the climate of the North Atlantic, and, more in general, of the Northern Hemisphere: the temperatures may drop by a few degrees, depending on the location," Daniele Castellana, from Utrecht University, The Netherlands, told Newsweek.

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Image showing the movement of water in the North Atlantic Current. The current has shut down many times over Earth's history. Sven Baars, University of Groningen

Castellana is lead author of a study that looked at what might happen to the AMOC over the coming centuries. Previously, researchers had looked at its stability and what might happen if it collapses. However, few models have factored in the fluctuations of freshwater being fed to the North Atlantic at the surface, through meltwater from Greenland and rainfall. They call this influx "noise."

In a study published in Scientific Reports, Castellana and colleagues focused on the noise and its effect on the current. "We believed that this effects can't be ignored: our results confirmed our hypothesis," he said.

Their model showed that, based on current noise, the chance of the AMOC temporarily shutting down in the next 100 years is around 15 percent. They also found there is almost no chance it will completely collapse in the next 1,000 years.

"It is good news that a complete shutdown is very unlikely to happen due to the effect of noise," he said. "However ... our model does not take into account considerable changes in freshwater in the North Atlantic, which can be caused by the melting of the ice sheets."

Castellana said their findings "strongly depend on the background state of the climate." If no action is taken to limit global warming, the Intergovernmental Panel for Climate Change (IPCC) predicts temperatures may increase by over four degrees Celsius by 2100. Studies show that increased warming will lead to more melting of ice sheets, and potentially their collapse.

Castellana said more research will be needed to understand how future climate may impact the AMOC. He said he and his colleagues are currently testing their results against different models, including those from the IPCC.

In a statement, study author Fred Wubs, from the University of Groningen, said: "Confirming our results through simulation with a high-resolution climate model will be the next challenge."

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View from San Sebastian, Basque Country, Spain. Researchers say there is a 15 percent chance the North Atlantic Current could shut down temporarily in the next 100 years.