July 12, 2019
The Arctic Ocean’s Sea Ice Hit Record Low Levels this June
News Source: Pacific Standard
Author(s): Gloria Dickie
In just a few months, the blanket of ice covering the Arctic Ocean has gone from a deep dish to a thin crust. Though sea ice has been thinning out across the Arctic for more than a decade due to climate change, the state of ice this spring and early summer is especially bad.
Researchers at the Polar Science Center recently released their monthly PIOMAS modelof the sea ice volume average in the Arctic for the month of June—and it revealed a grim decline. With just 3,814 cubic miles of ice left across the vast Arctic Ocean, this June nearly set a record average low for ice volume for the month, falling short by a mere 120 cubic miles of the average volume for June of 2017, the record holder.
But the bad news didn't end there—during the last days of June, daily ice volume loss escalated rapidly falling to just 2,890 cubic square miles at the end of the month, which is 25 cubic miles lower than June 30th, 2017, which puts 2019 at a record low volume for this time of year.
"In terms of the volume, it's definitely been pretty steep," says Walt Meier, a senior research scientist with the National Snow and Ice Data Center. "It's dropping precipitously for this time of year, and it's setting us up for a potential record in terms of volume."
According to the PIOMAS model, Arctic sea ice volume is currently 29 percent below the mean value for 1979 to 2018. Unlike sea ice extent, which is tracked via satellite imagery, the PIOMAS model relies on observations and various data points, like atmospheric temperatures, to produce an estimation of what's happening underneath the ice. But the model does have a high confidence level, and the estimation of ice volume loss tracks closely with the decline we've witnessed in sea ice extent across the Arctic this spring.
Extent has also just achieved a new record low for this time of year, with 2019 at 3.219 million square miles, taking the lead over record-holding 2012 for the moment, which had 3.227 million square miles of ice as of July 10th. It also appears likely that the Northeast Passage shipping route along Russia's polar coast could open within days, earlier than any time on record.
"The ocean has been very warm," Meier says. The Beaufort and Chukchi seas up around Alaska and Russia experienced early losses this spring that opened up the dark unreflective waters to further warming via the absorption of solar energy. "It's not uncommon for the Beaufort and Chukchi to open up earlier than we used to, but this was pretty extreme."
Ice can lose volume through several processes. Hotter air temperatures can melt the ice from above, while clear, sunny skies allow the increasingly ice-free ocean to absorb more heat energy from the sun's rays. When that happens, the warmed water laps away at the underside of ice floes, gobbling up many meters of thickness in some instances. In recent years, these processes have decimated thick, multiyear ice.
In addition to the Beaufort and Chukchi seas, the Canadian Arctic Archipelago saw a significant loss in ice volume this year, with a 20-mile-wide crack of open water appearing along its edge. Often, the Archipelago is a holdout of thick ice, but not this year.
What does all this mean for September, when sea ice extent and volume will reach their minimum, the lowest points in the annual cycle?
Right now, we're tracking closely with 2012, which experienced record lows in both volume and extent (2012 still holds the record for extent). However, 2012 wasn't as sunny and warm as it has been this year—the reason it smashed records was because a cyclone moved into the Arctic in August of 2012, melting ice and pushing what remained out of Arctic waters.
"It's been a very good set-up for rapid loss of ice early in the season—one of the better ones," says Meier, with low cloud cover, sunny skies, and hot air temperatures. "But 2012 had that big storm that pushed things down. We might be in a more optimal set-up than 2012, but will we get that final kick?"
As always in the Arctic, the answer depends on weather—whether or not fierce ice-destroying storms arrive before September; whether or not more multiyear Arctic ice is forced out into the warmer North Atlantic "killing zone;" and whether or not the polar region stays hot and sunny, or turns cool and cloudy. Only time will tell. But whatever this year's minimum, the Arctic death spiral is exceedingly likely to worsen in the years ahead—triggering an escalation of unpredictable but intensifying temperate zone extreme weather in decades to come.