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Monday, September 12, 2011

Neven, Climate Progress: The New Arctic Abnormal: Record Low Sea Ice Volume, Area, and Extent*

The New Arctic Abnormal: Record Low Sea Ice Volume, Area and Extent*

by Neven, guest, Climate Progress, September 11, 2011

AFP:  The area covered by Arctic sea ice reached its lowest point this week since the start of satellite observations in 1972, German researchers announced on Saturday…
“This is a new historic minimum,” said Georg Heygster, head of the Physical Analysis of Remote Sensing Images unit at the University of Bremen…
The Arctic death spiral continues.  We are reaching the climax of the Arctic sea ice melt season.  I asked Neven of the must-read Arctic Sea Ice Blog to set the scene for the finale (with some cool animations):
– by Neven of Arctic Sea Ice Blog
The incredible has happened. In the past week the 2011 melting season has started to surpass record year 2007. First, the good people from the Polar Science Center informed us of the fact that their PIOMAS model is showing a new sea ice volume record (as discussed here on Climate Progress).  A day later a new all-time low on the Cryosphere Today sea ice area graph was reached. And two days after that the same thing happened on the University of Bremen sea ice extent chart.  See figure above.
In a sense, this isn’t so incredible, as we have been well aware that this could happen from the start of the melting season. The winter maximum and of course sea ice volume were both relatively low. But what does make it incredible, is the way that freak melting season 2007 has been equaled and even surpassed in some data sets.
Four years ago, weather conditions that on average occur every 20 years or so, brought huge amounts of heat into the Arctic via air and water, flushed large amounts of ice through Fram and Nares Strait and – to top if off – compacted the ice pack so hard at the end of the melting season that the minimum extent was finally reached in the last week of September.
Up until mid-July this year’s melting season resembled that of 2007, but after that things fell apart on the atmospheric front. The heat had been brought in alright, but the flushing through Nares (which opened late) and Fram was slow, and in these last weeks of the season there isn’t much compaction to speak of, as the winds are too fickle to stay in place for a prolonged period.
Despite all this, 2011 is right down there battling it out with 2007 on almost every graph. This is a sure sign that the ice is very weak and thin in large parts of the ice pack, which means that perfect weather conditions conducive to melting and compacting are no longer necessary to break records. The ice will melt out in place, regardless of what the weather does. That doesn’t bode well for years to come.
On the image below (courtesy of NSIDC) we see some of the special features of the ice pack in this melting season.
Both the Northwest Passage and the Northern Sea Route have opened up. As this has happened almost every year since 2007, it has become one of those new normals, but I thought I’d mention it anyway (yes, I’m being sarcastic). Shipping companies have begun sending Suezmax-class tankers through the Northern Sea Route.
More interesting is the fact that more than half of of the ice in the channels between the Queen Elizabeth Islands (that part of the Canadian Archipelago between the Northwest Passage and the Arctic Ocean) has melted out completely. This used to be the place where the thickest and oldest sea ice of the Arctic would gather, pressed together by the winds. Not anymore. Last year we saw how ice floes from the Arctic Ocean flowed between the islands when the buttresses disappeared, into warmer southerly waters. This year the winds have been blowing in the wrong direction and so the ice in those channels has simply vanished and not been replaced. There will be thinner first year ice there, meaning it will melt out earlier next year.
This melting season is about to end. We have to wait and see if new minimums will be reached on the two popular extent graphs from IJIS and NSIDC. With the current weather forecast I’d say the odds are against that happening, but this only underscores the new abnormal in the Arctic: despite adverse weather conditions this melting season is on a par with the 2007 freak melting season. If these general circumstances persist, the Arctic will be very close to becoming ice free by the end of summer before 2020. Sooner, if we get a melting season with the same weather conditions as 2007.
No one knows what this will do to Northern Hemisphere weather patterns in the short run, and what happens with the permafrost and methane clathrates in the medium-to-long run. I don’t find that a particularly comforting thought.
– Neven
* The asterisk is for the fact that the record low sea ice extent is currently only in the Bremen record.  And yes, satellite observations of Arctic sea ice actually do date back to 1972.

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