Among the many devastating effects caused by global warming is the slowing down of deep ocean circulation mega-currents.

If we knew since a study published in August 2021 in the journal Nature Climate Change that the mega-current AMOC (Meridian Atlantic Overturning Circulation) was in danger, a new study published in the same journal on December 22 reports the same risk for SMOC (meridional southern overturning circulation) to the south,

Geo

reports .

These currents are driven by the differences in temperature and salinity between the water masses.

The warming of the water thus gradually slows down this circulation.

According to the latest estimates from researchers at the University of California at Irvine, in the worst-case scenario of global warming, GCOS could completely stop as soon as 2300. In the not so distant future, GCOS and AMOC are likely to slow down by 42 % by 2100.

A vicious circle

"This would mean a climate disaster similar in scale to the melting of all of Earth's ice caps," said oceanographer J. Keith Moore, associate professor and co-author of the study, in a statement.

In concrete terms, these mega-currents have the role of capturing and storing the CO2 emissions released into the atmosphere.

This process is made possible by the plankton, which comes to synthesize the carbon solubilized in the water inside their shell for several thousand years.



Clearly, the slowdown in these mega-currents will therefore aggravate the phenomenon of global warming, which in particular causes this same slowdown.

At the same time, the role of the oceans as a “carbon sink” could also be reduced due to the weakening of the biological activity of marine micro-organisms.

However, according to the authors of the latest Nature Climate Change study, these two phenomena would still be reversible if humanity limits its greenhouse gas emissions.

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