Study: Bering Sea's Ice at Lowest Levels in Thousands of Years
2020-09-10
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1Scientists are reporting that ice cover in the Bering Sea decreased during the winters of 2018 and 2019 to levels not seen in thousands of years.
2Reuters news agency says the new report adds to concerns about the effect of climate change in the Arctic.
3The Bering Sea is in the northern Pacific Ocean, between Russia and the American state of Alaska.
4The scientists said satellite images and records provide a clear picture of how the sea ice has changed over the past 40 years.
5Before that, the only ice records available were from those found in ship records and other observations.
6So, scientists turned to peat land on Saint Matthew Island, off the coast of Alaska.
7Peat is plant tissue that breaks down in wet conditions.
8It can hold organic substances from plants that lived thousands of years ago.
9The researchers studied different forms of oxygen molecules trapped in the peat land.
10With this information, they were able to estimate atmospheric and ocean conditions that would have affected rainfall and sea ice over a period of 5,500 years.
11The researchers reported their findings in Science Advances, a publication of the American Association for the Advancement of Science.
12St. Matthew "island in itself has acted as its own weather station," said Matthew Wooller, one of the researchers.
13He likened the levels of soil in the peat to a "book going back in time."
14Wooler is director of the Alaska Stable Isotope Facility at the University of Alaska Fairbanks.
15Many studies have shown that the Arctic has warmed in recent years.
16Sea ice levels in the area around the North Pole have decreased.
17This year, the summertime Arctic sea ice reached its lowest level for the month of July in 40 years of record keeping.
18Sea ice builds up again each year during the winter.
19But the new study suggests that, in the Bering Sea, sea ice may also be decreasing during cold weather.
20The loss of sea ice is already hurting Arctic wildlife, such as walruses, polar bears, and seals.
21The loss of sea ice also affects indigenous communities that depend on hunting for food and clothing.
22Shrinking sea ice intensifies warming in the Arctic.
23That is because areas of dark water take the place of the sea ice.
24The dark water absorbs, or takes in, solar radiation instead of reflecting it back into the atmosphere.
25"If we lose the sea ice you are completely changing the temperatures of the Arctic," noted Julienne Stroeve, who was not involved in the study.
26She is a climatologist with the National Snow and Ice Data Center at the University of Boulder Colorado.
27The study suggests that changes in the flow of ocean waters and atmospheric conditions linked to climate change have had a big effect.
28So says Miriam Jones, the lead writer of the study.
29She is a geologist with the U.S. Geological Survey.
30"There's a lot more going on than simply warming temperatures," Jones said.
31"We're seeing a shift in circulation patterns both in the ocean and the atmosphere," she added.
32In addition, the study suggests that changes in sea ice take place at least 20 or more years after changes in carbon dioxide and other heat-trapping gases.
33Stroeve suggested that the study could have been strengthened with more comparisons to information gathered by ships and whaling expeditions dating back to the 1800s.
34I'm Mario Ritter Jr.
1Scientists are reporting that ice cover in the Bering Sea decreased during the winters of 2018 and 2019 to levels not seen in thousands of years. Reuters news agency says the new report adds to concerns about the effect of climate change in the Arctic. 2The Bering Sea is in the northern Pacific Ocean, between Russia and the American state of Alaska. 3The scientists said satellite images and records provide a clear picture of how the sea ice has changed over the past 40 years. Before that, the only ice records available were from those found in ship records and other observations. 4So, scientists turned to peat land on Saint Matthew Island, off the coast of Alaska. Peat is plant tissue that breaks down in wet conditions. It can hold organic substances from plants that lived thousands of years ago. 5The researchers studied different forms of oxygen molecules trapped in the peat land. With this information, they were able to estimate atmospheric and ocean conditions that would have affected rainfall and sea ice over a period of 5,500 years. 6The researchers reported their findings in Science Advances, a publication of the American Association for the Advancement of Science. 7St. Matthew "island in itself has acted as its own weather station," said Matthew Wooller, one of the researchers. He likened the levels of soil in the peat to a "book going back in time." 8Wooler is director of the Alaska Stable Isotope Facility at the University of Alaska Fairbanks. 9Many studies have shown that the Arctic has warmed in recent years. Sea ice levels in the area around the North Pole have decreased. This year, the summertime Arctic sea ice reached its lowest level for the month of July in 40 years of record keeping. 10Sea ice builds up again each year during the winter. But the new study suggests that, in the Bering Sea, sea ice may also be decreasing during cold weather. 11The loss of sea ice is already hurting Arctic wildlife, such as walruses, polar bears, and seals. The loss of sea ice also affects indigenous communities that depend on hunting for food and clothing. 12Shrinking sea ice intensifies warming in the Arctic. That is because areas of dark water take the place of the sea ice. The dark water absorbs, or takes in, solar radiation instead of reflecting it back into the atmosphere. 13"If we lose the sea ice you are completely changing the temperatures of the Arctic," noted Julienne Stroeve, who was not involved in the study. She is a climatologist with the National Snow and Ice Data Center at the University of Boulder Colorado. 14The study suggests that changes in the flow of ocean waters and atmospheric conditions linked to climate change have had a big effect. So says Miriam Jones, the lead writer of the study. She is a geologist with the U.S. Geological Survey. 15"There's a lot more going on than simply warming temperatures," Jones said. "We're seeing a shift in circulation patterns both in the ocean and the atmosphere," she added. 16In addition, the study suggests that changes in sea ice take place at least 20 or more years after changes in carbon dioxide and other heat-trapping gases. 17Stroeve suggested that the study could have been strengthened with more comparisons to information gathered by ships and whaling expeditions dating back to the 1800s. 18I'm Mario Ritter Jr. 19Matthew Green reported this story for Reuters. Mario Ritter Jr. adapted it for VOA Learning English. George Grow was the editor. 20Words in This Story 21indigenous - adj. produced, living or existing naturally in an area 22reflecting - v. to strike a surface and go back in the opposite direction 23circulation - n. the movement of air or water through an area 24expedition - n. a trip undertaken by a group of people for a purpose 25We want to hear from you. Write to us in the Comments section, and visit our Facebook page.