Alaska Sea Ice Extent Collapses; Bering Sea Not Just At Record Low - 1/2 Of Prior Record Low
April should be prime walrus hunting season for the native villages that dot Alaska’s remote western coast. In years past the winter sea ice where the animals rest would still be abundant, providing prime targets for subsistence hunters. But this year sea-ice coverage as of late April was more like what would be expected for mid-June, well into the melt season. These conditions are the continuation of a winter-long scarcity of sea ice in the Bering Sea—a decline so stark it has stunned researchers who have spent years watching Arctic sea ice dwindle due to climate change.
Winter sea ice cover in the Bering Sea did not just hit a record low in 2018; it was half that of the previous lowest winter on record (2001), says John Walsh, chief scientist of the International Arctic Research Center at The University of Alaska Fairbanks. “There’s never ever been anything remotely like this for sea ice” in the Bering Sea going back more than 160 years, says Rick Thoman, an Alaska-based climatologist with the National Oceanic and Atmospheric Administration.
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The occurrence of these unusual conditions off Alaska this past winter can largely be chalked up to the random weather variations in a chaotic climate system, Bond, Walsh and Thoman all say—but they add that global warming likely amped up the severity of the situation. A study Walsh co-authored in the January Bulletin of the American Meteorological Society found that although The Blob was ushered in by natural variations, without climate change it likely would not have been as intense as it was. And whereas the Bering Sea has had plenty of winters as stormy as this one, the underlying warming trend means such winters can have a much bigger impact on sea-ice formation in today’s climate.
The lack of sea ice is not just hitting walrus hunting hard; throughout the winter and spring, coastal communities have seen substantial flooding and erosion during storms without much of the usual sea ice to act as a buffer. What little there is has been very thin stuff local residents call “junk ice,” Thoman says: “It wasn’t very much better than no ice at all.”
At the end of April the Bering Sea was nearly ice-free—four weeks ahead of schedule. With the sun shining on the Arctic again, the open ocean is soaking up heat that could set up another delayed freeze-up again next fall. Because of the role the weather plays, though, “every year is not going to be like this,” Thoman says. “Next year will almost certainly not be this low.” But as temperatures continue to rise, he says, “odds are very strong that we will not go another 160 years before we see something like this” happen again.
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https://www.scientificamerican.com/article/shock-and-thaw-alaskan-sea-ice-just-took-a-steep-unprecedented-dive/
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