According to current research, ocean currents in the Atlantic Ocean may have lost so much stability that this system could collapse. This is the result of a study in the specialized journal Nature Climate Change, published by the Potsdam Institute for Climate Impact Research (PIK) on Thursday. Warnings are given about the consequences for weather systems around the world.
The study deals with the Atlantic meridian inversion circulation (AMOC), which also includes the Gulf Stream. AMOC transports warm water masses from the tropics on the sea surface to the north and cold water on the sea floor to the south, which is relatively mild Temperatures in Europe It is of great importance,” PIK explained.
‘Approaching a critical threshold’
“The AMOC system is one of the most important circulation systems on our planet,” explained study author Niklas Boers of the Potsdam Institute for Climate Impact Research, Freie Universität. Berlin and University of Exeter. He noted that in Earth’s history, the AMOC had already assumed a much weaker alternative state in addition to the current strong state. In principle, sudden transitions between these two states are also possible.
According to the study, the current system is “as weak as it has been in the last thousand years.” According to Boyers, it was not yet clear whether this was only related to a change in the average trading condition or an actual loss of dynamic stability. “The difference is crucial,” Boyer stressed, because the decrease in dynamic stability means that “a transition to the hemodynamic poor mode may be irreversible in practice.”
Numerous evidence suggests, according to Boyer, that weakness “may mean approaching a critical threshold beyond which the circulation system can collapse”.
The researchers were surprised by the rapid change
Additional factors that can be added to the direct effects of the warming of the Atlantic Ocean on its circulation are mentioned in the study. This includes the influx of fresh water from melting Greenland’s ice sheet, melting sea ice, and increased precipitation and from river waters. Fresh water reduces the tendency of water in the North Atlantic to sink from the surface to greater depths, which is one of the drivers of turbulence.
“I did not expect that the additional amounts of fresh water that have flowed into the ocean over the past century would actually elicit such a response from the AMOC,” Bowers said. Therefore, current models “urgently need to align with the available observations” in order to “evaluate how much the AMOC in fact remains below the critical threshold value”. Even if the significance of each of the different factors still needs to be studied, they are in any case “associated with man-made climate change”.