In most climate model projections, changes to the Atlantic Meridional Overturning Circulation (AMOC) are both gradual and moderate.

However, according to a new paper published 4 January 2017 in Science Advances, the consensus may be due to bias built into the models. New research suggest that the AMOC is more unstable than previously thought. In fact, authors Wei Liu, Shang-Ping Xie, Zhengyu Liu, and Jiang Zhu of Yale University, say, “By correcting the model biases, we show that the AMOC collapses 300 years after the atmospheric CO2 concentration is abruptly doubled from the 1990 level.”

Long-term (after 300 years) responses of surface temperature and precipitation to CO2 increase. (A, C, and E ) Results of annual mean temperature (shading in °C): (A) the CTLCO2 minus the CTL (C) the ADJCO2 minus the ADJ, and (E) the difference between (C) and (A). (B, D, and F) Similar to (A), (C), and (E) but for the results of annual mean precipitation (shading in mm day−1). Photo courtesy of Liu, et al.

The result? The researchers say, “Compared to an uncorrected model, the AMOC collapse brings about large, markedly different climate responses: a prominent cooling over the northern North Atlantic and neighboring areas, sea ice increases over the Greenland-Iceland-Norwegian seas and to the south of Greenland, and a significant southward rain-belt migration over the tropical Atlantic.”

To read the full article, click here.

Source:
Wei Liu, Shang-Ping Xie, Zhengyu Liu and Jiang Zhu, “Overlooked possibility of a collapsed Atlantic Meridional Overturning Circulation in warming climate,” Science Advances 04 Jan 2017: Vol. 3, no. 1, e1601666, DOI: 10.1126/sciadv.1601666