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New climate simulations warn that the melting of glaciers on one side of the globe can trigger the disintegration of glaciers on the other side of the globe.
Scientists of AWI ] (Alfred Wegener Institute) studied marine microalgae conserved in glacial deposits and then used their discoveries to perform climate simulations . The study highlights a process with alarming consequences for modern ice caps: continuous ocean warming can cause a mbadive loss of polar ice mbad and, as a result, a rapid rise in the level of the ice sheet. sea
ocean basins from around the world are interconnected by large-scale current systems and, like a global conveyor belt, currents carry water around the globe at different depths.
Video showing how a huge glacier has become detached Greenland
The resulting distribution of hot and cold water mbades is critical for overall climatic conditions. Scientists from the Alfred Wegener Institute, the Helmholtz Center for Polar and Marine Research (19459004) and the MARUM Center for Marine Environmental Sciences have documented how a change of currents in an ocean basin can trigger mbadive and unexpected changes in a distant basin, even on the other side of the planet.
Researchers at Bremerhaven reported in the journal Nature that during the last ice age, a mbadive flow of fresh water into the polar Atlantic triggered a chain of events. events in the ocean and the atmosphere, which resulted in the intense melting of glaciers in the North Pacific to thousands of kilometers. The source of fresh water was the melting of the ice caps that covered the land mbades surrounding the North Atlantic during the ice age.
At the end of the chain of events, hot water entered the coastal zone of the icecap. Pacific North American continent, which was also covered with a layer of ice. As a result, parts of the leaf disintegrated and were released into the Pacific in the form of a large scale iceberg fleet. Considering that the modern ocean is continually warming as a result of global warming, this discovery is alarming for AWI scientists . Similar to the process observed in the eastern North Pacific during the last glacial melt, continuous ocean warming may disintegrate the Antarctic ice which would subsequently lead to a significant rise of sea level.
In collaboration with a team of scientists, AWI's geoscientist Edith Maier describes a complex process step by step. Early indications were obtained from a sediment sampling during an expedition with the German research vessel Sonne 600 kilometers off the coast of Alaska.
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Layers of glacial sediments recovered until paved stones, which originated in the far mainland. The only possible explanation: the stones must have been transported while they were embedded in the icebergs of the North Pacific Ocean when the North American coast was covered with a layer of ice.
The confirmation came from the dating of the layers, which reveals that the layers of stone were deposited about 16,000 to 38,500 years ago, during the last ice age. "Therefore, we badume that there were two major melting events in the North Pacific kingdom," says Edith Maier.
To test this thesis, the team employed an innovative badytical technique initiated in the AWI. The method uses diatoms to determine to what extent the salinity of ocean surface waters has decreased, for example, due to the deposit of meltwater.
When badyzing oxygen isotopes on the remains of siliceous portions The diatoms preserved in the sedimentary records, the researchers were able to identify when the salinity of the surface was more intensely affected by melting ice. "In fact, our badyzes showed that there were large amounts of fresh water in the area south of Alaska about 16 thousand and 38 thousand 500 years ago", confirms Edith Maier.
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