Mexico-Size Chunk of Ice Missing from the Arctic

The Arctic is lacking a piece of sea ice the scale of Mexico.

Whereas fall ushers within the season of sea ice progress, November noticed a transient retreat that was just about unprecedented in practically 40 years of satellite tv for pc data, based on knowledge launched Tuesday by the Nationwide Snow and Ice Knowledge Heart. That dip helped November set a report low for sea ice space — the seventh month to take action this yr, additionally a report.

On the reverse pole, the ocean ice fringing Antarctica additionally set a report low for November, reversing a number of years of report highs, although what's driving the flip-flopping is not clear.

"It is vitally placing this November in each hemispheres," NSIDC scientist Julienne Stroeve mentioned in an e mail. "It actually is constant the long-term decline in Arctic sea ice. It is a bit extra interested in what is occurring in Antarctica, so extra analysis on that's wanted."

Uncommon Chilly Season Retreat

Arctic sea ice follows a seasonal cycle, waxing throughout the chilly, darkish months of fall and winter, and waning when the solar re-emerges in spring and summer time.

 

Arctic sea ice extent for November 2016 was three.51 million sq. miles. The magenta line exhibits the 1981 to 2010 median extent for the month. The black cross signifies the geographic North Pole.

Credit score: Nationwide Snow and Ice Knowledge Heart

However skyrocketing Arctic temperatures, that are rising twice as quick as the worldwide common, have set off a downward spiral in sea ice ranges. Summer time has seen the most important decline, with the end-of-season minimal half of what it was simply three many years in the past.

 

A latest examine discovered that emissions of carbon dioxide equal to that from a single transatlantic flight interprets to a lack of 30 sq. ft of sea ice. If emissions aren't introduced beneath management and temperatures proceed to rise, the Arctic might change into ice-free throughout summer time by the center of the century.

That lack of ice impacts regional wildlife, native communities, and industrial actions like transport. It could even exert an affect on climate patterns of North America, Europe and Asia.

The top-of-winter most this yr hit a report low due to remarkably heat winter circumstances within the Arctic, with air temperatures four°F to 11°F (2°C to six°C) above common. However comparatively cool and cloudy summer time climate saved the summer time minimal from beating out the 2012 report low.

Because the solar set for the winter, ice started to develop like normal, although it stayed nicely under regular week after week.

Then, in mid-November, an odd factor occurred: the ocean ice started to say no. Earlier than it resumed its upward trajectory, sea ice space dropped by 19,300 sq. miles — a feat just about unprecedented within the data. The one comparable prevalence was a a lot smaller drop of 5,400 sq. miles in November 2013.

That uncommon cold-season dip helped November end with a sea ice space 753,000 sq. miles under the 1981 to 2010 long-term common for the month (although the expansion price of sea ice was barely greater than common), only a bit smaller than the realm of Mexico.

Not a 'Tipping Level'

The unusual cold-season dip in sea ice extent was brought on by persistent southerly winds pulling in heat air and heat ocean waters that saved sea ice from forming within the Barents Sea, an space north of Scandinavia and japanese Russia. Sea floor temperatures there have been as much as 7°F (four°C) above regular throughout November close to Norway's Svalbard Peninsula.

"Sometimes sea ice begins to type within the fjords originally of November, however this yr there was no ice to be discovered," Stroeve, who was in Svalbard throughout the month, mentioned in a press release.

Sea ice additionally dropped unusually sharply in Antarctica, which is nearing summer time. The common November extent there was 699,000 sq. miles under the 1981 to 2010 common, greater than twice earlier report low for month. NSIDC scientists assume the decline was as a result of hotter air temperatures and a speedy change within the air present that whips across the continent.

In earlier years, Antarctic sea ice hit report highs, probably as a result of altering ocean circumstances linked to the melting of land-bound glaciers. However polar scientists say there's nonetheless a lot to find out about what drives the conduct of Antarctic sea ice, which is kind of totally different than its Arctic cousin.

Stroeve and different sea ice researchers do not assume this yr's Arctic ice data mark a tipping level, or some extent the place such loss turns into irreversible. Scientists fearful about reaching such a point-of-no-return when sea ice first plummeted to a report low in 2007, nevertheless it has since rebounded (although the long-term decline continues) and if warming is introduced beneath management, sea ice can develop again.

"I nonetheless do not assume now we have a tipping level solely as a result of the ice might come again if we restrict the warming — it isn't irreversible," Stroeve mentioned.

It's attainable, although, that such a chilly season retreat might change into extra frequent as world, and Arctic, temperatures, proceed to rise.

"I feel that is one thing we would anticipate to see extra of sooner or later," Walt Meier, a NASA sea ice researcher, mentioned. "With much less ice in the summertime and extra warming of the ocean, there's extra warmth out there close to the ice that may be pushed (by winds) into the ice [and] a minimum of briefly soften again some ice early within the progress season."

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