One of the most complex, but also potentially catastrophic consequences, of global warming is the risk that the increase in the temperatures of the waters of the seas has an effect on ocean currents. For example, the possibility that the Gulf current, which among other things mitigates the winters of western Europe, could slow down or stop or stop, and now a new study published on Environmental Research Letters It points the finger on the wider system of currents that includes it: it is called southern reversal of the Atlantic circulation, but is more known with the English acronym Amoc, and according to a group of Dutch researchers not only risks collapsing, but to do so even long before expected.
The current that “does” the Atlantic. The AMOC current (by the way, the abbreviation is for Atlantic Southern Overturning Circulation) flows throughout the northern Atlantic to the equator (and even a little further south), bringing the water to the north that is heated by the tropics sun. Here, this water cools down, sink into it and returns to flow south. This water movement effects on the entire Basin of the North Atlantic, and has a huge impact on the entire ocean system.
Sooner or later it will collapse. He is also undergoing the effects of heating of ocean waters: he has not been so weak for 1600 years, and already in 2021 a German researcher from the Potsdam Institute of Climate Impact Research, Niklas Boers, warned in a study against the possibility that the amoc could collapse within a few decades, with catastrophic consequences on the whole oceanic ecosystem and not only. Since then, all climatic models have foreseen that the current will collapse sooner or later – the problem is that, says the new study, we have been all too optimistic about when.
Point of no return. All the models used so far to simulate the evolution of the AMOC claimed that a collapse was unlikely before 2100. The Dutch team, however, used models that prolonged the simulation time until 2300 and then to the 2500: these new models paint a downtime for the future of the AMOC. If we continue with current emissions, in fact, there is a 70% probability that the Atlantic current reaches its own Tipping Pointthe point of no return, in the next 10 or 20 years. From that moment on complete collapse they could go from 50 to 100 years, but it would be a countless account without hope: after passing a certain threshold, the fate of the AMOC will be marked.
What do the most optimistic models provide? Even the most optimistic models, which are based on a reduction in emissions in line with the Paris agreements, certainly do not let joy, since they foresee 25% probability that the current slows down irreparably by 2100 and from there it will face a rapid collapse.
It is a much higher percentage than what we had calculated so far, which stopped at 10% probability. Which, according to the authors, is however too high: in their work they warn against the collapse of this current, which would have irreversible consequences globally. And even if he could stop collapse, the Amoc will still continue to slow down, at least for a while: this will already have consequences on the climate, in particular the European one.
