SOURCE: Washington Post
DATE: June 26, 2018
SNIP: Scientists studying one of the fastest-warming regions of the global ocean say changes in this region are so sudden and vast that in effect, it will soon be another limb of the Atlantic, rather than a characteristically icy Arctic sea.
The northern Barents Sea, to the north of Scandinavia and east of the remote archipelago of Svalbard, has warmed extremely rapidly — by 2.7 degrees Fahrenheit just since the year 2000 — standing out even in the fastest warming part of the globe, the Arctic.
[T]his warming is being accompanied by a stark change of character, as the Atlantic Ocean is in effect taking over the region and converting it into a very different entity.
While the Southern Barents is milder, the northern Barents has — until recently — had all the characteristics of an Arctic sea. It featured floating sea ice that, when it melted, helped to provide an icy, freshwater cap atop the ocean. This kept internal heat from escaping to the atmosphere, and also kept the ocean “stratified” — cold, fresher waters at the surface and warmer, Atlantic-originating waters down below.
This situation, which obtains in much of the Arctic, was reinforced by the fact that freshwater is less dense than salt water, preserving stratification.
But that’s changing. Less sea ice is floating down through the northern Barents Sea from higher Arctic latitudes, the research shows.
Indeed, the lack of sea ice in the northern Barents Sea has been a regular feature of charts lately — at this very moment, an enormous stretch of ocean in this area that has traditionally been ice covered is currently open.
As the ice recedes, the ocean surface in turn receives less fresh water from its melting.
And 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.”
“This region is shifting to the Atlantic climate, and it’s going fast,” said Sigrid Lind, a researcher with the Institute of Marine Research in Tromsø, Norway.
“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,” the study concludes.
It could also have major weather consequences, some scientists believe. Indeed, those may already be occurring.