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By Guest Nicole
The changes are already visible in the region, which has had largely ice-free summers since 2011
The Arctic is undergoing an astonishingly rapid transition as climate change overwhelms the region.
New research sheds light on the latest example of the changes afoot, showing that parts of the Arctic Ocean are becoming more like the Atlantic. Warm waters are streaming into the ocean north of Scandinavia and Russia, altering ocean productivity and chemistry. That’s making sea ice recede and kickstarting a feedback loop that could make summer ice a thing of the past.
“2015 was a really anomalous year when we had problems finding a suitable ice flow to launch our drifting buoys,”Igor Polyakov, an oceanographer at the University of Alaska who led the new study, said. “(There was) nothing like that in the past, and it became a motivation to our analysis: why was ice in 2015 so rotten? What drives this huge change?”
The findings, published in Science on Thursday, show that while warming air has a role to play, processes are playing out in the ocean itself that are fundamentally altering the region.
Those changes will have impacts on the people, plants and animals that call the Arctic home. They could also create more geopolitical tension as resources previously locked under ice become available and shipping lanes open up.
In the east Arctic Ocean, the shift is manifesting itself in changing the layers of the ocean. There’s a cap of cold, less salty water that covers the eastern portion of the Arctic Ocean. Underneath it sits a pool of warm, salty Atlantic water that until recently hasn’t been able to find a way to surface. That stratification of layers has kept ice relatively safe from its warm grip.
The ocean has become gradually less stratified since the 1970s. Using data from buoys and satellites, Polyakov and his colleagues have found a more marked shift over the past decade and a half. Since 2002, the difference in water temperatures between the layers has dropped by about 2°F.
In winter from 2013-2015, the cap separating the deep water and surface water disappeared completely in some locations, allowing the warm Atlantic waters to reach the surface and cut further into sea ice pack. At the same time, warm air has further reduced sea ice, which is allowing still more mixing of the ocean layers.
The result is a feedback loop that is essentially turning roughly a third of the eastern Arctic Ocean into something resembling the ice-free Atlantic Ocean.
“Rapid changes in the eastern Arctic Ocean, which allow more heat from the ocean interior to reach the bottom of sea ice, are making it more sensitive to climate changes,” Polyakov said. “This is a big step toward the Arctic with seasonal sea-ice cover.”
The changes are already apparent in the region, which has largely been ice-free during the summer since 2011. The sea ice winter maximum, which has set a record low for three years running, has been largely driven by a lack of ice in the eastern Arctic.
Polyakov said he’s seen the rapid changes in ice firsthand. When they first put buoys in the eastern Arctic in 2002, researchers had to reach the sites on heavy icebreakers.
“Now we can reach them using an ice class ship,” he said. Ice class ships are not necessarily as reinforced as icebreakers.
The sea ice changes are having profound impacts outside of researchers’ ability to access more remote sites. Other research published earlier this week in Science Advances shows that thinning sea ice is allowing phytoplankton to bloom across the region.
Phytoplankton are tiny plants, and like your average potted plant, they need sunlight to bloom. Sea ice has been thick enough to prevent that from happening until very recently. The new findings show that over the past decade, up to 30 percent of the Arctic has become primed for summer blooms.
“Both of our results show the Arctic becoming a very different place than it has been in the past,” Christopher Hovart, an oceanographer at Harvard who led the plankton study, said. “Water pathways are changing, the ecology is changing, all driven by the declining sea ice field.”
This article is reproduced with permission from Climate Central. The article was first published on April 6, 2017.
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By Guest Nicole
Every winter, the Arctic Ocean’s sea ice cover reaches a peak and then declines with the onset of spring. That peak, recorded this year on Thursday, was the lowest seen in 37 years of record keeping, federal scientists said yesterday.
Sea ice covered just 5.6 million square miles of the Arctic Ocean on Thursday, about 5,000 square miles less than the previous record set last year, according to the National Snow and Ice Data Center (NSIDC) and NASA. The 1981-2010 average sea ice extent was 6 million square miles.
The Arctic is a portent for climate change, as it is warming at a faster rate than the rest of the planet. Some scientists think the loss of sea ice during wintertime leads to atmospheric “waves” that propel the polar vortex into the Lower 48 states (ClimateWire, Aug. 18, 2014). Between 1975 and 2012, sea ice in the central Arctic Basin has thinned by 65 percent, according to a study published in Cryosphere in February last year.
“The Arctic is in crisis,” Ted Scambos, a glaciologist at NSIDC, said in a statement. “Year by year, it’s slipping into a new state, and it’s hard to see how that won’t have an effect on weather throughout the Northern Hemisphere.”
The record low sea ice levels were triggered by a “warm, crazy winter,” said Mark Serreze, director of NSIDC, in a statement. “The heat was relentless.”
Temperatures over the Arctic Ocean between December and February were an unprecedented 4 to 11 degrees Fahrenheit higher than normal, particularly around the edges where the ice is thin.
Alaska witnessed the third consecutive winter to be significantly warmer than average, and the winter was the driest on record in parts of the state, Rick Thoman, climate science and services manager at the National Oceanic and Atmospheric Administration’s National Weather Service, said in a press briefing last month.
“Mark Twain said, ‘Climate’s what you expect; weather is what you get,’” he said. “This winter has not brought much of what we expect to Alaska.”
THE ‘UNRAVELING OF THE ARCTIC’
El Niño, which elevated temperatures around the world, might have played some role in the Arctic’s unusual warmth, said Jennifer Francis, a climate scientist at Rutgers University. She pointed to the atmospheric circulation system as a possible culprit, as well.
A cold blob of water has persisted in the north Atlantic Ocean, and it has consistently pushed storms into Europe, she said. As a side effect, pulses of heat and moisture from these storms have sometimes traveled as far as the North Pole. This may have slowed ice formation and pushed the ice edge northward, she said.
Other scientists pointed to warming oceans as a potential cause. The ice extent was below average in the Barents Sea due to an influx of warm Atlantic Ocean waters from the Norwegian Sea, said Ingrid Onarheim, an oceanographer at the Bjerknes Centre for Climate Research in Norway.
This region is keenly watched by scientists who expect the ocean’s heat conveyor belt, the Atlantic Meridional Overturning Circulation, which transports heat from the tropics to the tip of Greenland, to slow down due to climate change. This would stop the influx of warm waters and lead to a temporary recovery of the wintertime sea ice extent, said Julienne Stroeve, a climate scientist at NSIDC.
Whatever the cause, the new sea ice low is a signal of significant shifts in northern latitudes, said Rafe Pomerance, former deputy assistant secretary of State and chairman of Arctic 21, a coalition of nongovernmental organizations concerned with climate change in the region.
“Not only is the sea ice in steep decline, but snow cover in spring in the Northern Hemisphere, permafrost is thawing, we are losing the Canadian and Alaskan glaciers, and Greenland is shrinking,” he said. “It is a signal of the continuing unraveling of the Arctic.”
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