This year’s Arctic sea ice minimum is now officially the second lowest in the record according to the National Snow & Ice Data Center in the US. On August 26, the ice extent stood at 5.26m km2, dropping below 2005’s 5.32m km2. The melt season still has several weeks left to run, and there are now suggestions that this year’s final minimum could be close to – perhaps even beat – last year’s record.
The NSIDC announcement has attracted a flurry of attention, and the media has been out trawling the usual suspects for quotes. The BBC reports:
Researchers say the Arctic is now at a climatic “tipping point”. “We could very well be in that quick slide downwards in terms of passing a tipping point,” said Mark Serreze, a senior scientist at the Colorado-based NSIDC. “It’s tipping now. We’re seeing it happen now,” he told the Associated Press news agency.
Following last summer’s record minimum ice cover in the Arctic, current observations from ESA’s Envisat satellite suggest that the extent of polar sea-ice may again shrink to a level very close to that of last year.
Meanwhile, Scientific American notes that the northwest passage is now open, and the Environment News Service does an admirable job of pulling all the info together – including recent work on possible rapid climate change around the Arctic. Earlier this month I was prepared to accept that I was going to lose my two bets on a new record minimum this year, so what’s been going on up north to change the outlook so dramatically?
Here’s one of the ESA’s interesting pictures – an animated graphic showing sea ice changes over the summer, which I’ve edited to include only the last two frames (full version is here). It’s pretty clear what’s been going on…
In early August there was a large amount of ice in the Chukchi Sea (near the top of the frame), which by mid-month had all but disappeared. You can also see that much of the ice near the top edge of the ice pack, especially in the Beaufort Sea north of Alaska, and in a wedge running towards the north pole from Siberia is heavily fractured, with large amounts of open water. The same structures can be seen in the imagery at Cryosphere Today and the University of Bremen. How much of that goes over the next few weeks will determine whether we get a new record or not.
What’s been most unusual about this year has been the steep decline in ice extent during August, as this graph from the NSIDC shows:
2008’s extent was well above 2007 from the end of June onwards, but was tracking 2005 closely. Early this month, this year’s melt accelerated (see red arrow), and is now getting down towards 2007 (you can check the daily update of this graph at the top of the NSIDC news page). There’s a similar graph (based on different data) at the Japanese IJIS site. Interestingly, Cryosphere Today, which uses a different measure of sea ice – the area, not extent – seems to show that the melt is now slowing down. The next few weeks are going to be fascinating for ice watchers…
The fat lady is still in her hotel, enjoying some vintage champagne, and my money’s still in my wallet.