Levels of rainfall also increased in Europe, while other parts of the world, such as parts of Africa, experienced drier conditions and extended periods of drought.
Temperatures in the North Atlantic and Europe dropped by between 1.5 and 5 degrees C and lasted for about 200 years, with other regions experienced above average warming. Heat energy drives the world’s climate and the disruption to the ocean current had major ramifications around the world. Instead, Dr Rush and his colleagues believe the melting of the Hudson Bay Ice Saddle which covered much of eastern Canada and the north-eastern United States provided the injection of vast quantities of water that was reflected in the core samples. The view held by many scientists was that the freshwater had come from a giant lake - Lake Agassiz-Ojibway, which was the size of the Black Sea and was situated near what is now northern Ontario -which had drained into the ocean.ĭr Rush said: “We have shown, that although huge, the lake was not large enough to account for all that water going into the ocean and causing the sea-level rise that we observed.” The analysis of the core samples provides further evidence that there were at least two major sources of freshwater that drained into the North Atlantic, causing the changes to the AMOC, and not a single source as previously thought. The research team took core samples from the sediment in the Ythan Estuary to build up a picture of what was happening to sea levels 8,000-plus years ago.įrom analysing microfossils and the sediment in the samples, they found that sea-level changes departed from normal background fluctuations of around two millimetres a year and reached 13 millimetres a year with individual sea-level events resulting in water rising most likely by about 2 metres in the Ythan Estuary.įossils of a single celled organism Elphidium gerthi. It is believed that an influx of a massive amount of freshwater into the salt-water seas of the North Atlantic caused the AMOC to breakdown. The change in AMOC also affected global rainfall patterns. More than 8,000 years ago, the North Atlantic and Northern Europe experienced significant cooling because of changes to a major system of ocean currents known as the Atlantic Meridional Overturning Circulation, or AMOC. Using geological samples from the Ythan Estuary in Scotland, scientists have identified a melting ice sheet as the probable trigger of a major climate-change event just over 8,000 years ago.Īnd the analysis - involving a team of geo-scientists from four Yorkshire universities led by Dr Graham Rush, who holds positions at both the University of Leeds and Leeds Beckett University - could hold clues as to how present-day ice loss in Greenland could affect the world’s climate systems.
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