Friday, August 06, 2021

Key Atlantic Ocean current system could be collapsing

The Atlantic Meridional Overturning Circulation includes the Gulf Stream and circulates warm water to the ocean's surface that contributes to mild temperatures in Europe.


 File Photo by Victoria Lipov/Shutterstock

Aug. 5 (UPI) -- A major Atlantic Ocean current system may be declining in strength, which could have consequences for weather systems worldwide, according to a study released Thursday.

The study, published in Nature Climate Change, found evidence that the Atlantic Meridional Overturning Circulation is approaching a collapse. The current system includes the Gulf Stream and circulates warm water to the ocean's surface that contributes to mild temperatures in Europe, according to a press release announcing the study.

Niklas Boers, an author of the study and researcher at the Potsdam Institute for Climate Impact Research, Freie Universität Berlin and Exeter University, said in a statement that the Atlantic Meridional Overturning Circulation is one of the planet's "key circulation systems."

Likened to a conveyor belt for oceans, the circulation system plays an important role in distributing heat globally. While there is evidence that the system is at its weakest point in more than a thousand years, the study examined whether it's becoming less stable.

"The difference is crucial because the loss of dynamical stability would imply that the AMOC has approached its critical threshold, beyond which a substantial and, in practice, likely irreversible transition to the weak mode could occur," Boers said.

Data measuring the AMOC does not exist, according to the researchers. But the system leaves "fingerprints" from sea-surface temperature and salinity patterns that the study used to find evidence that it is becoming less stable and could collapse.

The study found that factors linked to climate change are contributing, including the freshwater inflow from the melting of the Greenland ice sheet and sea ice, as well as precipitation and river runoff.

A different study published earlier this year found that the AMOC is the weakest it has been in a thousand years.

According to the United Kingdom's Meteorological Office, a weaker AMOC could bring less warm water northward and offset increasingly warm temperatures in western Europe. The office noted that a collapse of the system is unlikely before 2100. 

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