After nearly two decades of extreme warming, the northern Barents Sea is undergoing what the Washington Post calls a “stark change of character,” becoming “another limb of the Atlantic Ocean, rather than a characteristically icy Arctic sea.”
The region’s transformation will lead to shifts in Arctic marine ecosystems and may already be producing major weather impacts, the Post reports.
“This region is shifting to the Atlantic climate, and it’s going fast,” said Sigrid Lind, a researcher at the Institute of Marine Research in Tromsø, Norway, one of three authors of a paper published last week in the journal Nature Climate Change.
The last 18 years have made the northern Barents, located north of Scandinavia and east of the Svalbard archipelago, a standout even in the rapidly-warming Arctic, with warming of 2.7°F (1.5°C) since 2000. “Lind and her colleagues have shown, based on temperature and salinity measurements taken on summer research cruises, that this warming is being accompanied by a stark change of character, as the Atlantic is in effect taking over the region and converting it into a very different entity,” the Post states. “They underscore that the divide between the Atlantic and the Arctic isn’t just a geographical one—it’s physical in nature.”
Unlike the milder Southern Barents, the northern part of the sea had all the characteristics of an Arctic waterway until recently. “It featured floating sea ice that, when it melted, helped to provide an icy, freshwater cap atop the ocean,” explains climate reporter Chris Mooney. “This kept internal heat from escaping to the atmosphere, and also kept the ocean ‘stratified’—cold, fresher waters in the upper part of the ocean and warmer, Atlantic-originating waters down below.”
But now, with less sea ice floating down from more northerly latitudes, the northern Barents is changing fast.
“As the ice recedes, the ocean surface in turn receives less fresh water from its melting,” Mooney writes. “As that happens, the deeper Atlantic waters mix higher and higher toward the surface, not only warming the seas but also making them more salty. The result, the study says, has been a ‘dramatic shift in the water column structure in recent years.’ Arctic surface waters, with a temperature below freezing, are ‘now almost entirely gone.’”
The study concludes that, “unless the freshwater input should recover, the entire region could soon have a warm and well-mixed water column structure and be part of the Atlantic domain, a historically rare moment where we would witness a large body of water being completely transformed from Arctic to Atlantic type.”
Rutgers University Arctic specialist Jennifer Francis told the Post the loss of ice over the Barents and Kara seas could disrupt the atmospheric jet stream and produce extreme weather in Eurasia, particularly during the winter months. The shift will result in “persistent cold spells over East Asia and a disrupted stratospheric polar vortex, which effectively prolongs the original influence of the ice loss into late winter. We saw this happen in spades this past winter.”