An ocean current that circulates water throughout the Atlantic Ocean may collapse sometime this century, severely impacting the climate system of the North Atlantic region, according to a recent study.
Known as the Atlantic Meridional Overturning Circulation (AMOC), the ocean current brings warm water from the tropics toward the poles. In doing so, the AMOC brings warmer temperatures and nutrients necessary to sustain ocean life to more polar regions of the globe.
In the North Atlantic region, the AMOC includes the Gulf Stream, which carries warm water from the coast of Florida to western European countries. It also brings cooler and heavier saltwater from the North Atlantic down to the tropics. This movement of cooler water south and warmer water north creates a warmer climate for the western European countries, despite their relatively northern latitude.
Scientists have noted, however, that the AMOC has weakened over the past century, NOAA said. This weakening is the result of warming temperatures causing Greenland’s ice sheet to melt and introduce more freshwater into the North Atlantic. In doing so, NASA said it decreases the ocean water’s saltiness in the northern waters, thereby hampering the AMOC’s ability to circulate.
The authors note that the weakening of the current "is a major concern as it is one of the most important tipping elements in Earth’s climate system."
Recent assessments by the Intergovernmental Panel on Climate Change, based on model simulations, report while the AMOC is likely to weaken over the 21st century for all emissions scenarios, its research suggests that a full collapse of the current was unlikely within the 21st century.
But according to the recent study by researchers Peter Ditlevsen and Susanne Ditlevsen, they believe the AMOC is expected to collapse this century.
"We estimate a collapse of the AMOC to occur around mid-century under the current scenario of future emissions," the researchers said in the study, with a reported 95% confidence range of between 2025 and 2095.
In the scenario of the AMOC collapsing, it would likely result in abrupt shifts in regional weather patterns and water cycle, the authors said.
They added, "given the importance of the AMOC for the climate system, we ought not to ignore such clear indicators of an imminent collapse."
According to the study, the AMOC has been continuously monitored since 2004. To gain a more long-term perspective of trends, the study authors applied fingerprinting techniques to records of sea surface temperatures from earlier years.