The Gulf Stream reached its weakest level in about 1,000 years, concluded a scientific study published in the journal Nature Geoscience, which warns of the extreme consequences of this Atlantic change for the climate in Europe.
“Never in more than 1,000 years has the South Atlantic Circulation (AMOC), also known as the Gulf Stream system, been as weak as it has been in decades,” is the conclusion of this research carried out by scientists from Ireland. Great Britain and Germany.
The study analyzed the so-called “proxy data” from ocean sediments, water temperatures and ice cores that were hundreds of years old and, based on this information, reconstructed the evolution of the current river and obtained “consistent evidence” of its slowdown in the 20th century unprecedented in the last millennium.
The researchers admit that this situation is related to climate change and stress the study that the Atlantic circulation is relevant to the climate patterns on the European continent.
“The Gulf Stream system works like a giant transmission belt, transporting hot water from the surface of the equator north and sending deep, cold water with low salinity to the south. It moves almost 20 million cubic meters of water per second, almost a hundred times as much as the Amazon, ”explains Stefan Rahmstorf from the Potsdam Institute for Climate Impact Research in Germany.
According to the researcher, the study’s conclusions suggest that the flow was relatively stable until the end of the 19th century, but decreased dramatically in intensity from the mid-20th century.
The 2019 Special Report on the Oceans of the Intergovernmental Panel on Climate Change (IPCC) “had already established that AMOC was weakened from 1850 to 1900,” recalls Stefan Rahmstorf, emphasizing that this new study “provides and establishes more independent evidence for this conclusion in a long-term paleoclimatic context ”.
“We use a combination of three different types of data to get information about ocean currents: temperature patterns in the Atlantic; Groundwater body properties; and grain sizes of seabed sediments ranging in age from 100 to about 1,600 years, ”explained Levke Caesar from the Department of Research and Climate Analysis at the University of Maynooth, Ireland.
The AMOC’s slowdown has already been predicted in climate models in response to global warming caused by greenhouse gases, which is disrupting the various water densities that are the source of the electricity.
In practice, the increase in rainfall and the melting of the Greenland ice sheets add fresh water to the sea surface, reducing the salinity and, consequently, the density of the water and weakening the flow of AMOC.
According to Levke Caesar, an additional slowdown for Europe could lead to more extreme weather events such as B. a change in the routes of winter storms, which could be more intense, as well as the occurrence of extreme heat waves or a decrease in rain levels. in summer.
“If we press ahead with global warming, the Gulf Stream system will continue to weaken according to the latest generation of climate models – 34% to 45% by 2100,” concluded Stefan Rahmstorf.