SOURCE: Yale News

DATE: July 31, 2017

SNIP: Arctic sea ice is not merely a passive responder to the climate changes occurring around the world, according to new research.

Scientists at Yale University and the University of Southampton say the ongoing Arctic ice loss can play an active role in altering one of the planet’s largest water circulation systems: the Atlantic Meridional Overturning Circulation (AMOC).

AMOC has a lower limb of dense, cold water that flows south from the north Atlantic, and an upper limb of warm, salty water that flows north from the south Atlantic as part of the Gulf Stream. AMOC plays a major role in regional and global climate, affecting the Atlantic rim countries — particularly those in Europe — and far beyond.

Earlier this year, a different Yale-led study cautioned that the AMOC system was not as stable as previously thought. That study said the possibility of a collapsed AMOC under global warming conditions is being significantly underestimated.

“We’ve now found this new connection between sea ice and AMOC,” Liu [Wei Liu, a Yale postdoctoral associate] said. “Sea ice loss is clearly important among the mechanisms that could potentially contribute to AMOC collapse.”

“In our experiments we saw a potential loss of 30% to 50% of AMOC’s strength due to Arctic sea ice loss. That is a significant amount, and it would accelerate the collapse of AMOC if it were to occur,” Fedorov [Alexey Fedorov, climate scientist at the Yale Department of Geology and Geophysics] said.