By Le Figaro with AFP
Published 3/30/2023 at 9:18 am, Updated 3/30/2023 at 9:40 am
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Icebergs break off from a glacier in Antarctica February 11, 2020. NASA/ Portal
Rapidly melting Antarctic ice threatens to dramatically slow deep-water currents in the oceans and limit the spread of freshwater, oxygen and nutrients for centuries, according to a study in the journal Nature.
Accelerating ice melt in Antarctica is likely to result in a “significant slowdown” in deep-sea water circulation if global carbon emissions remain high, according to new modeling, researchers said in a study published Wednesday.
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reversal of deep waters
According to the study, which warns of impacts that would last “centuryes”, the “reverse circulation” of water in the deep oceans would slow by 40% by 2050 if a high-emission scenario occurs. If the model is correct, the deep-sea current will be “on a trajectory that appears to be headed for collapse,” said Matthew England, a professor of climatology at the University of New South Wales (UNSW) who coordinated the study.
According to this study, trillions of tons of cold, very salty, oxygen-rich water flow around Antarctica each year, sending a deep current of water north into the Indian, Pacific, and Atlantic Oceans.
lungs of the ocean
However, greater amounts of melting ice are making Antarctic waters less dense and less saline, slowing deep water circulation and affecting climate, sea levels and marine ecosystems. “If the oceans had lungs, this would be one of them,” England said.
And when the oceans stagnate below 4,000 meters, “nutrients become trapped in deep waters, reducing the amount of nutrients available to marine life near the sea’s surface,” he added. UNSW Professor Emeritus John Church, who was not involved in the study, said there are many uncertainties about the impact of a decrease in deep-sea circulation.
“But it seems almost certain that persistently high greenhouse gas emissions will have even more profound impacts on the oceans and the climate system,” Church said. “There is an urgent need for the world to drastically reduce emissions to get off the high emissions path that we are currently following.”
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