Satellite imagery of the mostly ice-free Bering Strait on Feb. 28. 2019.
IMAGE: SENTINEL HUB EO BROWSER/SENTINEL 3
IMAGE: SENTINEL HUB EO BROWSER/SENTINEL 3
BY MARK KAUFMAN MAR 04, 2019
During winter, the Bering Strait has historically been blanketed in ice. But this year, the ice has nearly vanished.
"The usually ice-covered Bering Strait is almost completely open water," Zack Labe, a climate scientist and Ph.D. candidate at the University of California at Irvine, said over email.
At its narrowest point, the Arctic strait between the U.S. and Russia is 55 miles across, and there's a prominent theory that people once crossed from Asia into North America across an exposed Bering land bridge (back when sea levels were lower). In modern times, however, this frigid waterway usually builds ice through the winter, reaching its greatest extent in late March.
After that, the ice usually lingers for months.
"There should be ice here until May," Lars Kaleschke, a climate scientist at the Alfred Wegener Institute for Polar and Marine Research, said over email.
Lars Kaleschke@seaice_de
· Mar 3, 2019
There is something significant going on in the Bering Sea: a very low ice extent for the second year in a row.
Lars Kaleschke@seaice_de
A new record low sea ice extent for the day of the year in the Bering Sea. pic.twitter.com/DuznyRcKV4
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3:09 PM - Mar 3, 2019
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But now, in early March, the ice extent is the lowest in the 40-year satellite record, said Labe. On March 2 specifically, the ice extent was lowest on record for that day of the year, added Kaleschke.
Overall, the last two years have now seen exceptionally low ice cover in the Bering Sea, and there are a few reasons why.
In the longer-term, the Arctic is warming over twice as fast as the rest of the globe, leading to significant melting across much of the Arctic, even where the ice is the thickest, oldest, and most resilient. "The 12 lowest extents in the satellite record have occurred in the last 12 years," the National Oceanic and Atmospheric Administration's 2018 Arctic report concluded.
This Arctic warming is especially notable near the Bering Strait. "In the long-term, temperatures in northern Alaska have been rising faster than anywhere else in the United States," said Labe.
SEE ALSO: An appreciation of the persistently grim tweets from the Norway Ice Service
It was the warmest March on record for nearly all of Alaska. Deadhorse, Alaska, hit a whopping 40 degrees Fahrenheit above normal.
Here are the daily departures from normal for Deadhorse, AK the last 7 days:
+31.9°F above normal
+33.0°F above normal
+38.0°F above normal
+36.5°F above normal
+36.0°F above normal
+40.0°F above normal
+38.4°F above normal
Exacerbating matters are storms in the Bering Sea, which roll through and batter whatever sea ice is left. There will be little to no sea ice here before the onset of summer, allowing the sea to stock itself with even more heat before the warm season, noted Rick Thoman, a climate specialist for the Alaska Center for Climate Assessment and Policy at the University of Alaska Fairbanks.
Meanwhile, after a long, sun-drenched summer, the melted Arctic reaches its lowest sea ice extent, or minimum, in late September. This year promises to fit the trend: The 12 lowest ice extents on record have all occurred in the last 12 years.
"The changes in the Arctic are happening faster than they’re happening anywhere else on the rest of the planet," Jeremey Mathis, a NOAA oceanographer, told Mashable.
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