Antarctic ocean currents headed for collapse, driving 'mass slowdown' in water circulation

The rapid melting of Antarctic ice poses a threat to halt deep ocean currents, which would have a negative impact on the climate, the movement of fresh water and oxygen, as well as nutrients necessary for life, for centuries, as per claims from the scientific community, reported by DW. 

Deep ocean currents surrounding Antarctica may slow by more than 40% over the course of the next 30 years, according to a recent study that was published in the journal Nature on Wednesday. According to the study, in a high-emission scenario, the "overturning circulation" of the ocean's deep waters will reduce by 40% by 2050, with consequences lasting "for generations to come."

'Substantial slowdown' of water circulation in the deepest ocean basins

If global carbon emissions continue to be high, new modelling used in the paper revealed that rapid Antarctic ice melts will cause a "substantial slowdown" of water circulation in the deepest ocean basins.

If the model is accurate, Matthew England, a climate professor at the University of New South Wales (UNSW), who oversaw the study, said the deep ocean circulation will be "on a trajectory that appears headed towards collapse."

Every year, trillions of tonnes of water sink around Antarctica, carrying with it a deep-water current that flows northward into the Indian, Pacific, and Atlantic seas. When more ice melts, the density and salinity of the Antarctic waters decrease, delaying the deep-ocean circulation.

The study claims that future change is still uncertain since dynamic ice-sheet melt is not taken into consideration in the most recent coordinated climate model estimates.

Oceans beneath 4,000 metres would become stagnant if this deep ocean movement stopped. As a result, there would be fewer nutrients available to support marine species close to the ocean surface.

"This would trap nutrients in the deep ocean, reducing the nutrients available to support marine life near the ocean surface," as per England. 

The study also predicted that as the globe warms, the melting of the Antarctic and Greenland ice sheets will continue to speed up. England stated, "We are talking about the possible long-term extinction of an iconic water mass.