Study shows that collapse of the critical Atlantic current system is more likely than thought

Study shows that collapse of the critical Atlantic current system is more likely than thought

The Atlantic overturning circulation could be headed toward an abrupt, “cliff-like” closure.

A systematic collapse of Atlantic currents pushing warm water from the tropics toward Europe may be more likely than researchers previously expected — an event that would drop temperatures across much of the continent, a study published on Friday warned.

The Atlantic Overturning Circulation (AMOC), which includes the Gulf Stream, could go into a relatively abrupt shutdown, said René van Westeren, who led the Dutch study published in 2019. Advancement of sciencecalled “Like an Abyss”.

Over thousands of years, the Gulf Stream carried warm waters from the Gulf of Mexico north along the east coast of North America and across the Atlantic Ocean to Europe. As human-caused global heat melts the Greenland ice sheet, massive amounts of fresh water are released into the North Atlantic, cooling the AMOC — which provides the bulk of the Gulf Stream’s heat — toward a “tipping point” that could stop the current. In its paths.

Closing the AMOC would cause temperatures to rise in the Southern Hemisphere, but to fall significantly in Europe. In the study model, London cools by an average of 18 degrees Fahrenheit, and Bergen, Norway, by 27 degrees Fahrenheit. A failure of the AMOC would also cause sea levels to rise along the east coast of North America.

“We are getting close to (the collapse), but we are not sure how close we are,” Van Westen said. Associated Press. “We are heading towards a turning point.”

According to the study:

Although AMOC collapses have occurred in complex global climate models due to the strong forcing of freshwater, AMOC inversions have not been investigated so far. Here we present the results of the first overturning event in the Community Earth System Model, including the large climate impacts of the collapse. Using these results, we develop a physics-based, observable early warning signal about the AMOC overturn: the minimum freshwater transport induced by the AMOC at the southern boundary of the Atlantic Ocean. The reanalysis products indicate that the current AMOC is on its way to transition. The early warning signal is a useful alternative to classical statistical signals, which, when applied to a simulated transition event, have been shown to be sensitive to the time interval analyzed before the transition.

“The research makes a compelling case that the AMOC is approaching a tipping point based on a strong, physically based early warning indicator,” said Tim Linton, Director of the Global Systems Institute at the University of Exeter. “What you can’t and don’t say is how close the tipping point is, because there’s not enough data to make a statistically reliable estimate of that.

“We have to plan for the worst,” added Linton, who was not involved in the Dutch study. “We must invest in collecting relevant data and better estimating how close the tipping point is, better assessing its impacts, and preparing in advance how to better manage and adapt to these impacts if they begin to emerge.”

Stefan Rahmstorf – who leads the Department of Earth Systems Analysis at the Potsdam Institute for Climate Research in Germany and was not part of the new study – described the research as “a major advance in the science of AMOC stability.”

“The new study adds significantly to the growing concern about the collapse of the AMOC in the not-too-distant future,” Rahmstorf said. Associated Press. “We will ignore this at our peril.”

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