It seems that the Arctic sea ice has reached its minimum area for the year. The record for reduction from last year has not been broken, but the situation is nonetheless disturbing. Whereas last year provided optimal conditions for melting, the unusually cold winter last year – arising from La Nina conditions – meant that this year’s melt should have been quite a bit less significant. As it happened, it was within 10% of last year’s record.
Walt Meier, a scientist at the American National Snow and Ice Data Center explained the situation:
I think this summer has been more remarkable than last year, in fact, because last year we had really optimal conditions to melt a lot of ice. We had clear skies with the Sun blazing down, we had warm temperatures, and winds that pushed the ice edge northwards. We didn’t have any of this this year, and yet we still came within 10% of the record; so people might be tempted to call it a recovery, but I don’t think that’s a good term, we’re still on a downwards trend towards ice-free Arctic summers.
In short, the Arctic ice is probably already locked into a death spiral. Here’s hoping that doesn’t lead to widespread melting of the permafrost, since the results of that would be catastrophic for humanity.
What do the models say concerning the extra energy absorbed by an ice-free pole?
Also, doesn’t this account of “ideal freezing conditions” ignore impact of open water on melting?
I don’t think most climatic models quantify the Arctic ice albedo feedback.
Daily status reports on the north polar ice can be found on the NSIDS website.
It would be interesting to see the relative importance of the open water feedback compared to temperature fluctuations in surface waters of the tropical Eastern Pacific Ocean, as enablers of melting.
Related prior posts
Sea Ice reaches second lowest minimum extent in 2008
Category: cryosphere • news
Posted on: September 16, 2008 1:10 PM, by coby
Some notable facts from the article:
* this is the second-lowest minimum extent since at least 1979, when satellite observations became available
* the area is now 2.24 million km^2 below the 1979-2000 average summer minimum
* this year did not set a new record, (congratulations Stoat!) stopping at 9.4% more than the record-setting 2007 minimum
* this measurement reinforces the downward trend observed over the last decades, and is well below that trend line
* this minimum was reached despite overall cooler summer temperatures
‘Catastrophic’ melt threat to polar life
4:00AM Wednesday Sep 17, 2008
Data showing Arctic sea ice may reach its lowest level on record this summer underscores the need for governments to speed up talks on a new climate pact, says the Worldwide Fund for Nature.
Observations on ice coverage and thickness show a record low for the second year in a row, continuing a “catastrophic” trend that may threaten polar wildlife and quicken global warming, the WWF said this week.
The penultimate meltdown
Despite cooler weather, Arctic ice retreat just misses last year’s mark
Posted by Joseph Romm (Guest Contributor) at 5:27 PM on 18 Sep 2008
Objection: Sea ice at the north pole recovered a whopping 9.4 percent from 2007 to 2008 despite the doom and gloom predictions of the alarmists. Yet another wheel falls off the global warming bandwagon.
Answer:
It is true that the minimum summer ice extent in the arctic ocean in 2008 was 9.4 percent higher than the minimum in 2007. But calling this a recovery is simply not justifiable, not by a long shot. Firstly, at 4.52 million square kilometers, this measurement is 2.24 million square kilometers below the average minimum observed since 1979, when accurate satellite observations began, so we are nowhere near getting back to normal levels of ice cover (source: NSIDC). Secondly, year to year fluctuations are very large and simply reflect the chaotic nature of weather — the change over a single year does not say anything meaningful about climate trends.
Reconciling sea ice models with reality
The study was published in Nature Geoscience (subscription) by Julien Boé and his colleagues at UCLA. They calculate that the models showing the fastest future ice loss are also the most realistic about the recent past – something you could guess at by looking at the graph above, where the actual ice trend is shown as a black line. So rather than simply averaging across models, their technique teases out the most likely future sea ice evolution using the differences between the models that show the 1979-2007 ice extent most accurately and those that perform less well at reproducing past trends (if you’ve a yen for statistics it’s worth checking out the paper itself – the method is explained in a neat graphic). They project, based on a moderate emissions scenario, that September sea ice will most likely disappear between 2066 and 2085. That is sooner than even the most pessimistic models suggest on their own (see graph again).
‘Gruelling’ Arctic mission ends
By David Shukman
Environment Correspondent, BBC News, Eureka, Canadian Arctic
The Catlin Arctic Survey, a gruelling 10-week expedition to measure the thickness of sea ice, has ended.
At 1750 BST on Wednesday, two planes landed safely on the floating Arctic ice to collect Pen Hadow, Ann Daniels and Martin Hartley.
Their data will help study the impacts of global warming in the region.
It also reinforces a new forecast, by a leading UK scientist, who says that the Arctic sea ice could vanish in summertime far sooner than predicted.
The Catlin survey ended slightly ahead of schedule to ensure a safe pick up.
Speaking on a live link from the Arctic landing strip, Mr Hadow said that it had been a difficult but successful expedition.
“In our time here we have captured around 16,000 observations and [taken] 1,500 measurements of the thickness of the ice and snow as well as its density,” he said.
He added that his team was now handing its valuable data, collected primarily through drilling following the failure of a mobile radar unit, over to the scientists.
“[The data] seems to suggest it was almost all first-year ice,” Mr Hadow said.
He revealed that over the length of the survey the average thickness of the sea ice was 1.774m.
June 3, 2009
Melt season gains momentum
After a slow start to the melt season, ice extent declined quickly in May. Scientists are monitoring the ice pack for signs of what will come this summer. The thinness of the ice pack makes it likely that the minimum ice extent will again fall below normal, but how far below normal will depend on atmospheric conditions through the summer.
Pause in Arctic’s melting trend
By Richard Black
Environment correspondent, BBC News website
This summer’s melt of Arctic sea ice has not been as profound as in the last two years, scientists said as the ice began its annual Autumn recovery.
At its smallest extent this summer, on 12 September, the ice covered 5.10 million sq km (1.97 million sq miles).
This was larger than the minima seen in the last two years, and leaves 2007’s record low of 4.1 million sq km (1.6 million sq miles) intact.
But scientists note the long-term trend is still downwards.
They note that at this year’s minimum, the ice covered 24% less ocean than for the 1979-2000 average.
The analysis is compiled from satellite readings at the US National Snow and Ice Data Center (NSIDC) in Boulder, Colorado.