2019 sea ice volume sinks to near record for June


  • High temperatures and relentless sun throughout the spring have caused Arctic sea ice volume to plummet, nearly setting a record low for the month of June. Sea ice extent has also plummeted, setting a new record low as of July 10.
  • At the end of June, 15,900 cubic kilometers (3,814 cubic miles) of ice remained in the Arctic Ocean, coming within a mere 500 cubic kilometers (120 cubic miles) of setting a new ice volume record for the month. 2017 still holds the June record, but just barely; accurate Arctic records have been kept since 1979.
  • On July 10, Arctic sea ice extent for 2019 fell to 8.338 million square kilometers (3.219 million square miles), surpassing 2012’s record low of 8.359 million square kilometers (3.227 million square miles).
  • While changing weather always dictates sea ice minimum extent and volume in September, scientists say that if conditions remain favorable for melt and ice export to the North Atlantic, then 2019 could beat all records. And because what happens in the Arctic doesn’t stay there, that could mean trouble for the world’s weather.
Arctic Ocean pack ice with polar bear. Image by Aweith licensed under the Creative Commons Attribution-Share Alike 4.0 International license.

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.

At the end of June, researchers at the Polar Science Center released their monthly PIOMAS model of sea ice volume in the Arctic — and it revealed a grim decline. With just 15,900 cubic kilometers (3,814 cubic miles) of ice left across the vast Arctic Ocean, this June nearly set a record low for ice volume for this time of year, falling short by a mere 500 cubic kilometers (120 cubic miles) above June 2017, the current record holder. As of the last few days of the month, ice volume was still declining at a record pace.

“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.”

Arctic sea ice extent on July 10, 2019. Image courtesy of Institute of Environmental Physics, University of Bremen, Germany.
Arctic sea ice volume, showing 2019 up to the end of June, when it nearly tied with 2017’s record low. Image courtesy of Wipneus using data from Polar Science Center.

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 8.338 million square kilometers (3.219 million square miles), taking the lead over record-holding 2012 for the moment, which had 8.359 million square kilometers (3.227 million square miles) of ice as of July 10. 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,” says Meier. The Beaufort and Chukchi seas up around Alaska and Russia experienced early losses this spring which 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.

Three different Arctic evaluation services all show sea ice extent at record lows on July 8-9, 2019 for the Arctic Basin, an area that is usually the last holdout during the melt season.. Data courtesy of Uni Hamburg, JAXA and NSIDC NASA.

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 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.

Banner image: Early summer in the Svalbard archipelago, a region where large amounts of Arctic ice are being exported into the North Atlantic “killing zone” this year. Imge by AWeith licensed under the Creative Commons Attribution-Share Alike 4.0 International license.

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This story first appeared on Mongabay

South Africa Today – Environment

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