New report warns of climate change threat to system driving Atlantic currents

A scientific report published Thursday is warning of looming threats against the system that regulates Atlantic Ocean currents, including a potential collapse due the impacts of human-induced climate change. 

The study, published in the Nature Climate Change scientific journal, found that the Atlantic Meridional Overturning Circulation (AMOC), which transports warm salt water from the tropics into the North Atlantic, is at its weakest point in more than 1,000 years. 

Niklas Boers, the study’s author, wrote that the “AMOC could be close to a critical transition to its weak circulation mode,” with a potential collapse of the system threatening to bring extremely cold temperatures to Europe and parts of North America, as well as raise sea levels along the U.S. East Coast and cause changes to monsoon patterns.

The report warned that with a warming atmosphere caused by a surge in greenhouse gases, the ocean surface is retaining more heat, potentially disrupting the AMOC, which serves as a primary component regulating the Northern Hemisphere’s climate. 

Boers, a researcher at the Potsdam Institute for Climate Impact Research in Germany, said, “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.” 

“The findings support the assessment that the AMOC decline is not just a fluctuation or a linear response to increasing temperatures but likely means the approaching of a critical threshold beyond which the circulation system could collapse,” Boers added. 

The study comes as the latest in a series of warnings that the AMOC is slowing down, though the Thursday report draws on more than a century of data on ocean temperature and salinity to show just how significant the changes are. 

While scientists have not reached a firm consensus on when a potential collapse of the AMOC could occur, climate scientists Richard Wood and Laura Jackson wrote in a February 2020 article that it is unlikely to happen this century. 

“Comprehensive climate models generally do not project a complete shutdown of the AMOC in the 21st century, but recently models have been run further into the future,” they wrote. “Under scenarios of continued high greenhouse gas concentrations, a number of models project an effective AMOC shutdown by 2300.”