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Берингов пролив — причина ледниковых периодов

The Bering Strait - the ocean, 80 kilometers wide, separating Russia and Alaska, can have a tremendous impact on the climate of the entire Northern Hemisphere. The results of the survey answer a question that has been pursuing scientists over the past decade, and they demonstrate how small changes in certain factors can affect the global climate.

For the past several million years, the Earth has been in a glacial cycle. Glacial periods occurred and occur with enviable regularity, lasting about 100,000 years and then waning for 10,000 to 15,000 years. The last such ice age ended about 11,000 years ago.

For several thousand years within each glacial period, thick kilometer-thick ice shells covering most of the “summits of the world” also went through certain cycles, thickening and thinning, stretching and retreating. But to date, no one could accurately determine the cause of these fluctuations.

At present, Aiksue Hu, an oceanographer at the US National Center for Atmospheric Research in Boulder, Colorado, and his colleagues have taken up this issue. They examined the potential effects of the Bering Strait on glacier oscillations. They knew that frequent periodic drops in sea level during past glacial periods created an isthmus through the strait. Analyzing data from ocean sediments, Hu's team determined that periods of changes in the isthmus appeared to be related to glacier fluctuations. Thus, in a new supercomputer model, researchers combined data from oceanic sediments, orbital stations, and Earth change cycles, which are known to cause or end glacial periods. The model shows that it was the Bering Strait that was the direct cause of the fluctuations of the continental ice.

Based on the above model, it was found that at the beginning of the ice age, massive layers of ice grow and move through North America, Greenland, Europe, and northern Asia. These glaciers isolate enormous masses of water, causing sea levels to drop, due to which a land bridge appears through the Bering Strait. When the strait is blocked in this way, water cannot circulate from the Pacific to the Arctic. The loss of a more saline and warm source allows the waters of the Atlantic Ocean to get an easy way into the Arctic. Atlantic waters, having a relatively high temperature, “melt” glacial strata, which, in turn, flood the Arctic seas and the Atlantic Ocean with fresh water, raising sea levels again and softening the northern climate. As the sea level rises,

It is still not precisely defined where and how warm waters interact with ice shells. To establish this, it is required to make additional studies, on the basis of which to design new computer models. burton.co.uk

Ronald Stuffer, a member of the National Oceanic and Atmospheric Administration in Princeton (New Jersey), agrees with the researchers report. However, he clarifies that a full understanding of the process described in the report takes time and so far a comparable model of continental ice cannot be developed, he said. In turn, the study improves our understanding of past climate change "and therefore gives us more confidence in the success of future designs."

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