early warning signs of the collapse of a sea current

A study published in the scientific journal Nature on August 5 found that the climate-controlling Gulf Stream was showing alarming signs of weakness. This suggests that we are approaching an important threshold. Its shutdown is one of the critical points identified by scientists, which can lead to a chain reaction. Global warming has been directly ruled out.

This will be a tipping point. The Gulf Stream, an ocean current that plays a major role in the balance of climate, is showing alarming signs of loss of stability, warns a study published August 5 in the scientific journal Nature Climate Change.

The Gulf Stream belongs to a larger group of currents called the AMOC or Atlantic Reversal Meridian Circulation. The current carries warm water from the tropics to the surface and cold water south to sea level. Thus by transmitting the heat of the Sun, it regulates the climate, and allows for milder temperatures in Europe. Therefore a possible collapse of this ocean current system could have dire consequences and lead to chain reactions.

If a previous study published in Nature in 2018 had already shown that the Gulf Stream was at its lowest level for 1,600 years, this new work sheds light that may be closer to the breaking point than we expected . “The results support the assessment that the decline in AMOC is not only a fluctuating or linear response to rising temperatures, but possibly reflects the approach of a critical threshold beyond which traffic systems may collapse.”, asked study author Niklas Boers from the Potsdam Institute for Climate Impact Research, the University of Exeter and the Free University of Berlin.

Global warming has been ruled out

Global warming is directly involved. The influx of fresh water from the melting of Greenland’s ice cap and sea ice, as well as increased precipitation and river runoff disrupt the functioning of the process. Soft water, lighter than salt water, prevents the stream from sinking deeper. “I didn’t expect that an excessive amount of fresh water has been added to produce such a reaction already in the last century. “, emphasizes the author.”There is an urgent need for us to adapt our models to the observations presented in order to assess how far the AMOC really is from its critical limit.

The CO2 emission limits leading to the collapse of the Gulf Stream are not known, the study author told the Guardian: “So the only thing to do is to keep emissions at their lowest. The likelihood that this phenomenon will have a very significant impact increases with each gram of CO2 we emit into the atmosphere.“.

Pauline Fricott, @paulinfricott

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