Story at a glance

  • Scientists behind the research have been studying oxygen isotopes in peat cores taken from St. Matthew Island in the Bering Sea.
  • The team determined ice cover during the winters of 2018 and 2019 hit incredibly low levels.
  • “What we’ve seen most recently is unprecedented in the last 5,500 years,” researchers said.

The extent of winter sea ice covering the Bering Sea in the Arctic is lower than it’s been for thousands of years, according to a paper published in Science Advances

Researchers from the University of Alaska Fairbanks analyzed vegetation from St. Matthew Island in the Bering Sea to estimate how sea ice in the region has changed over millennia. 


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“It’s a small island in the middle of the Bering Sea, and it’s essentially been recording what’s happening in the ocean and atmosphere around it,” Miriam Jones, a research geologist with the U.S. Geological Survey, said in a statement

Scientists behind the research have been studying oxygen isotopes in peat cores taken from the island and were able to estimate atmospheric and ocean conditions that would have affected rainfall and sea ice over 5,500 years. 

The team determined ice cover during the winters of 2018 and 2019 hit incredibly low levels. 

“What we’ve seen most recently is unprecedented in the last 5,500 years,” Matthew Wooller, director of the Alaska Stable Isotope Facility and contributor to the paper, said. “We haven’t seen anything like this in terms of sea ice in the Bering Sea.” 

Researchers said that while increasing temperatures are driving the melting of sea ice in the region, there’s more to the story. 

“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.” 

Shifts in ocean and atmospheric currents are also affected by climate change and play a larger role in the presence of sea ice.  

Ice in the Arctic Ocean has been melting each summer due to increasing temperatures over the last four decades. The northern polar region is warming at about three times the rate of the rest of the world. 

In July, Arctic sea ice extent was at the lowest level on satellite record

Published on Sep 02, 2020