Using geological samples from the Ethan Estuary in Scotland, scientists determined that melting ice sheets were the likely cause of a major climate change that occurred 8,000 years ago. Analysis by a team of geoscientists from four Yorkshire universities, led by Dr Graham Rush, of both the University of Leeds and Leeds Beckett University, could provide clues as to how current ice loss in Greenland could affect the world’s climate systems. .
More than 8,000 years ago, the North Atlantic and Northern Europe experienced significant cooling due to changes in the large ocean current system known as the Atlantic Meridional Overturning Circulation, or AMOC. A change in AMOC has also affected global precipitation patterns. The influx of large amounts of freshwater into the saline North Atlantic is thought to cause the AMOC to break.
The research team took core sediment samples from the Ethan Estuary to build a picture of what was happening at sea levels 8,000 years ago. By analyzing microfossils and sediments in the samples, they found that changes in sea level deviated from normal background fluctuations by about two millimeters per year and reached 13 millimeters per year, with individual sea level events most likely leading to a rise in water levels. about 2 meters. In the Itan estuary.
Fundamental analysis provides further evidence that there are at least two major sources of freshwater flowing into the North Atlantic, leading to changes in the AMOC rather than a single source as previously thought.
Many scientists believed that the fresh water came from a giant lake (Lake Agassiz-Ojibway, about the size of the Black Sea and located near present-day northern Ontario) that fell into the ocean. Dr Rush said: “We showed that although the lake was large, it was not large enough to account for all the water entering the ocean and causing the sea level rise we observed.”
Instead, Dr. Rush and his colleagues believe that melting in the Hudson Bay Ice Shelf, which covers much of eastern Canada and the northeastern United States, led to the injection of large amounts of water, which was also reflected in core samples.
Ocean circulation dissipates heat
Thermal energy affects the world’s climate, and disruption of ocean currents has had significant impacts worldwide. In the North Atlantic and Europe, temperatures continued to fall by 1.5 to 5 degrees Celsius for about 200 years; Other regions experienced above-average warming. Precipitation also increased in Europe, while other parts of the world, such as parts of Africa, experienced drier conditions and longer drought periods.
The study’s authors believe the study provides insight into how the current melting of the Greenland ice sheet could affect global climate systems.
Dr Rush added: “We know AMOC is now slowing down and, although it is still being debated, some predictions suggest it may stop altogether.
“But by looking at past events we can learn more about what caused these changes and how likely they are. The rapid retreat of Greenland’s ice sheet, which could occur depending on the trajectory of future fossil fuel emissions, could lead to a series of very worrying consequences.” “We have shown that it can cause significant climate impact.” Source
Source: Port Altele
