The system of currents in the Atlantic Ocean, an engine of climate in the northern hemisphere, could weaken to such an extent that it
triggers catastrophic changes worldwide
, according to a scientific study published Thursday.
The Atlantic Southern Reversal Circulation (AMOC) is a large system of ocean currents that carries warm water from the tropics to the North Atlantic.
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Climate models have shown that the AMOC is at its weakest in more than 1,000 years.
However, it is
unknown if this is due to a change in the flow of currents or if it is related to the loss of stability
.
The study, published in the journal Nature Climate Change, states that the difference is crucial.
“The loss of dynamic stability would imply that the AMOC has approached its critical threshold, beyond which a substantial transition could occur.
In practice,
it is probably irreversible
and generates weaker dynamics, "said Niklas Boers, a researcher at the Potstdam Institute for Climate Impact Research and author of the study.
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If the system changes significantly, the consequences would be dire, and could include faster sea level rise on the East Coast of the United States and in Europe, for example, as well as
stronger hurricanes in the southeastern United States.
Alex Hall, director of the Climate Science Center at the University of California, Los Angeles, who was not involved in the study, told The New York Times that while the findings do not indicate that the collapse of that ocean system is imminent, they are a reminder of the risks of interfering with currents.
"We are jabbing a beast," he said, "but we really don't know what reaction we will cause."
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Studying ocean systems is difficult for many reasons.
One of the challenges is that there is only one Earth, said Andrew Pershing, director of climate science at Climate Central, an organization of scientists and journalists focused on climate change.
Consequently, researchers cannot easily compare two oceans: an ocean with the effects of global warming caused by increased carbon dioxide in the atmosphere, and another that has not had to deal with that problem.
When consulted by The New York Times, Pershing praised the analytical solutions that scientists devised to study the tangle of currents that cross the ocean.
"That work is fascinating," he said, "the big challenge is, what do we do with that information?"
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By looking at sea surface temperature and salinity patterns in the Atlantic Ocean, the research says that the weakening experienced over the past century is likely associated with a loss of stability.
"The findings support the assessment that the AMOC decline is not just a fluctuation or a linear response to rising temperatures, but
likely means approaching a critical threshold beyond which the circulation system could collapse,
" he said. Boers.
The collapse of the AMOC would increase the cooling of the northern hemisphere, the sea level in the Atlantic would rise, it could also generate a general drop in precipitation in Europe and North America and a change in the monsoons in South America and Africa, he said. the Met Office of Great Britain.
Other climate models have said that the AMOC will weaken over the next century, but that a collapse is unlikely before 2100.
With information from NBC News and The New York Times