By Andrea Thompson on May 2, 2018 Read full Scientific American article here
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….
…The unusual warmth continued throughout this winter, in part because of an atmospheric pattern that kept warm air and storms periodically sweeping up from the south. One such event in February helped push the monthly temperature over the Bering and Chukchi seas some 18 to 21.5 degrees Fahrenheit (10 to 12 degrees Celsius) above normal. Consequently, the Bering Sea lost half its ice extent at a time when ice should still have been growing. The storms also pushed back against the normal southward flow of ice from the Chukchi Sea into the Bering. Accompanying winds stirred up waves that kept new ice from forming, and broke up what thin ice there was….
…“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.