Climate Model Suggests Collapse of Atlantic Circulation Is Possible

Typography

The idea of climate change causing a major ocean circulation pattern in the Atlantic Ocean to collapse with catastrophic effects has been the subject of doomsday thrillers in the movies, but in climate forecasts, it is mostly regarded as an extreme longshot.

Now a new paper based on analysis done at a group of research centers including Scripps Institution of Oceanography at the University of California San Diego shows that climate models may be drastically underestimating that possibility. A bias in most climate models exaggerates the stability of the pattern, called the Atlantic meridional overturning circulation (AMOC), relative to modern climate observations. When researchers removed the bias, and re-ran simulations, the result prompted them to predict a collapse of the circulation at some point in the future, setting off large-scale cooling in the north Atlantic. The collapse would stop the AMOC, which delivers warm surface water toward Greenland then sinks as it cools and flows back toward the equator closer to the seafloor.

The idea of climate change causing a major ocean circulation pattern in the Atlantic Ocean to collapse with catastrophic effects has been the subject of doomsday thrillers in the movies, but in climate forecasts, it is mostly regarded as an extreme longshot.

Now a new paper based on analysis done at a group of research centers including Scripps Institution of Oceanography at the University of California San Diego shows that climate models may be drastically underestimating that possibility. A bias in most climate models exaggerates the stability of the pattern, called the Atlantic meridional overturning circulation (AMOC), relative to modern climate observations. When researchers removed the bias, and re-ran simulations, the result prompted them to predict a collapse of the circulation at some point in the future, setting off large-scale cooling in the north Atlantic. The collapse would stop the AMOC, which delivers warm surface water toward Greenland then sinks as it cools and flows back toward the equator closer to the seafloor.

Wei Liu, a former Scripps postdoctoral researcher now at Yale University, Scripps climate modeler Shang-Ping Xie, and colleagues detail their findings in the paper “Overlooked possibility of a collapsed Atlantic Meridional Overturning Circulation in warming climate” appearing in the journal Science Advances today.

Read more at University of California - San Diego

Picture: North Atlantic Ocean cooling scenario following collapse of Atlantic Meridional Overturning Circulation

Photo credit: University of California - San Diego