A new study found early signs of a reorganization of the Atlantic ocean's circulation, which could have a significant effect on the global climate.
Researchers used a simulation from a complex model to look at the Atlantic Meridional Overturning Circulation (AMOC), which has a significant influence on the global climate system, the University of Exeter reported. The findings suggest these early warning signs show themselves as long as 250 years before the system collapses, which indicates scientists could predict an overturning of these circulations well in advance.
"We found that natural fluctuations in the circulation were getting longer-lived as the collapse was approached, a phenomenon known as critical slowing down," said lead author Chris Boulton.
The AMOC works like a conveyer belt that is driven by salinity and water temperature, it transports heat from the tropics and Southern Hemisphere to the North Atlantic. The recent findings suggest it is "switched off" when extra freshwater enters the North Atlantic; if this occurs the surface air temperature in the North Atlantic would cool by up to 8 degrees Celsius in the most dramatically affected regions. The effects could also cause droughts in the Sahel and changes in sea level along the coasts of Europe and North America.
"We don't know how close we are to a collapse of the circulation, but a real world early warning could help us prevent it, or at least prepare for the consequences" adds co-author Professor Tim Lenton.
The study was deemed the most realistic simulation of the climate system that focuses on early warning signs.
"The best early warning signals in the model world are in places where major efforts are going into monitoring the circulation in the real world -- so these efforts could have unexpected added value," Lenton said.
The findings were published in a recent edition of the journal Nature Communications.
