'For centuries to come' is the impact of melting Antarctic on oceans

By Al Mayadeen English
Source: Agencies
30 Mar 2023 08:53

The "overturning circulation" of waters in the deepest reaches of the oceans would slow down by 40% by 2050 in a high-emissions scenario, as per a new study.

A foraging Emperor penguin preens on snow-covered sea ice around the base of the active volcano Mount Erebus, near McMurdo Station, the largest US Science base in Antarctica, December 9, 2006. (Reuters)

Scientists warned that the rapidly melting Antarctic ice could drastically reduce deep-water currents, which would have long-term effects on the distribution of fresh water, oxygen, and nutrients necessary for life.

New modeling highlights that if global carbon emissions continue to be high, faster Antarctic ice melts will result in a "significant slowdown" of water circulation in the ocean depths, as per a report published in Nature on Wednesday.

The "overturning circulation" of waters in the deepest reaches of the oceans would slow down by 40% by 2050 in a high-emissions scenario, according to the study, which cautioned of impacts that would last "for centuries to come."

If the model holds true, the deep ocean current will be "on a trajectory that looks headed towards collapse," said University of New South Wales (UNSW) climate professor Matthew England, who coordinated the study.

Each year, scientists estimate that trillions of tonnes of cold, extremely salty, and oxygen-rich water sink around Antarctica, causing a deep-water current to flow northward into the Indian, Pacific, and Atlantic seas.

Yet, as more ice melts, the density and salinity of the Antarctic waters decrease, delaying the deep-water circulation, which has an impact on the climate, sea level, and marine ecosystems.

"If the oceans had lungs, this would be one of them," England said.

And if the oceans become stagnant below 4,000 meters, "this would trap nutrients in the deep ocean, reducing the nutrients available to support marine life near the ocean surface," he stressed.

It is worth noting that the study team comprised co-authors from the Australian National University and CSIRO, Australia's national research agency, as well as lead author Qian Li of the Massachusetts Institute of Technology.