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A study shows that winter ice in the Bering Sea, the northern Pacific Ocean between Alaska and Russia, has reached its lowest level in 5,500 years.
According to Agence France-Presse, the researchers analyzed the vegetation that had accumulated on the uninhabited island of San Mateo over the past 5,000 years and looked at the differences in the peat layers of oxygen atoms called isotopes 16 and 18, whose proportion in weather is related to atmospheric and oceanic changes and precipitation.
“It’s a little island in the middle of the Bering Sea, and it basically records what’s going on in the ocean and the surrounding atmosphere,” said Miriam Jones, a researcher who conducted the study at the University of Alaska and later at the American Geological Center.
Scientists studied a single 1.45-meter-long peat core taken from San Mateo in 2012, representing 5,500 years of accumulation.
“What we have seen recently is unprecedented in the last 5,500 years,” wrote Matthew Waller, director of the Alaska Stable Isotope Facility who participated in the analysis.
Ice in the Arctic and the Bering Sea melts in the summer and freezes again in the winter, but satellite observations only date back to 1979.
For the Arctic, the decrease in winter ice in recent decades has been evident and rapid, in parallel with global warming and increasing concentrations of carbon dioxide in the atmosphere.
But the study authors say that in recent decades the Bering Sea has seemed stable, with the exception of 2018 and 2019, when a significant decline was observed.
Source: Sputnik
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