Unofficially, for the moment, but Cryosphere Today, which doesn’t normally change its appearance much, has made the effort to point out that yesterday, August 9th, saw the lowest ever recorded Summer sea ice area. The link is here.
Bill Chapman also points out that there is still a way to go before the end of the melt season; the date at which Summer ice normally reaches the minimum varies, but in recent years hasn’t been before the end of August, and is ‘normally’ at the end of the first week in September. It could be as late as mid-September, especially this year. So we have between two and five weeks, with the latter being more likely, before the final Summer sea ice minimum for 2007 is reached.
As the old man projected this back in April, in itself it’s not a great surprise, but even I confess to a certain shudder when I look at the graphics on the various pages.
There’s a good graphic on the MMAB sea ice page, and excellent images on the PolarView/Damocles/IWICOS/IOMASA website. The latter don’t seem to like direct links, so you’ll need to hit the ‘overview’ link on the page. The image is then able to be enlarged substantially, showing the various grids quite clearly.
I’d draw your attention to a detail there which is also unusual, even in the context of recent sea ice declines; a close look at the Northern edges of Greenland and Ellesmere Island show that there is substantial thinning along much of the coastline. Whilst it is worrying to note the minimum in itself, this is a possible precursor to something which I haven’t seen discussed anywhere; the possibility of the Summer ice pack detaching itself completely from the land. This might have been something to expect in the coming years, but if it does happen that Kap Morris Jessup or Cape Columbia see open sea this year, it suggest that the calls for a review of the ‘standard’ expectations of future sea ice is now beyond urgent.
How low will it go? How much more melt are we going to see? If the NSIDC July graph is anything to go by, an extent anomaly (sorry for changing metrics mid-post) of -20% or more is plausible. In a year. On top of five consecutive years of record or near-record minima. And take a look at those graphs, like the hemispheric anomaly on CT; where is the variability? Where is the ‘natural’ ebb and flow of numbers caused by changing synoptics and interannual variations? This decline is, in climate terms, near-linear. So, here is the hypothesis. The Arctic Summer sea ice decline reached a tipping-point in 2002-3. Comments welcomed, as ever.
Be loved.
EDIT: RealClimate are commenting on this, too. Peter Hearnden has also linked to a satellite image, in the comments, if anyone is in doubt that the graphics are credible.. thanks, Peter.
Further edit: on the Rc site, mark Serreze has pointed us to the NSIDC’s re-launched weekly update site. Not this deals with sea ice extent, and monthly averages, a different system to CT’s. The picture is still grim. Link here.
11 comments
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August 10, 2007 at 3:45 pm
Peter Hearnden
“a close look at the Northern edges of Greenland and Ellesmere Island show that there is substantial thinning along much of the coastline.”
And a satellite picture to prove it š¦
http://www.woksat.info/etcph09/ph09-1046-f-grn-n.html
August 10, 2007 at 4:11 pm
fergusbrown
Thanks for that, Peter. It makes one wonder what the people over at Climate Science are imagining is going on; I’m wondering, too, if my comment there gets through Roger’s filter…
August 11, 2007 at 12:03 am
Gareth
Hi Fergus,
You might a few of the links at my Hot Topic post interesting, especially Jeff Masters’ blog…
August 11, 2007 at 12:21 am
fergusbrown
Hi Gareth; now, why is your name familiar? Good luck with the blog: I’ll be keeping an eye on it, as we have friends in NZ, and the CSC is a hoot!
As ever, though, the old man is curious how you found your way to the cave…
its a very obscure, out of the way sort of place.
Regards,
August 11, 2007 at 1:45 am
Gareth
Well, I do follow RC, globalchange, the Rabett hole, Open Mind etc, but only post infrequently, so you are not unknown to me. And it appears we are both interested in ice…
The Cave may be slightly less obscure than my other blog… (Google “truffle blog”, and On The Farm is six or seven down). It’s been languishing recently. Must get something up there soon…
Cheers
August 11, 2007 at 2:30 am
Kea
I found it, too, from the Climate Science blogs, not from Gareth.
August 11, 2007 at 11:25 am
fergusbrown
As a mycophile, I shall look with interest at your truffling exploits, Gareth. And welcome to you, too, Kea; it’s nice to see a physicist interested in the goings on here. Please feel free to express your thoughts or opinions about anything which attracts your interest… an overview on NZ conditions would be particularly welcomed.
Regards,
August 22, 2007 at 4:19 pm
Nick
I wonder, if the sea ice does separate from Greenland and Ellesmere, if the refreezing will be hampered by any circumpolar current generated by the settling of salt out of the sea water while it freezes. Would a West to East current around the ice reformation edge develop – and how might this affect change existing Autumn weather patterns.
August 22, 2007 at 4:30 pm
fergusbrown
The gaps appear to have vanished for the time being, Nick, though the ice concentration is probably still below average. Since writing this post I have read that such a phenomenon is unknown in living memory (though one might ask who would have noticed if it had happened 60 years ago?), so it’s just another small thing to get funny about. I don’t know if there’s such a connection between salinity and current, anyway.
Today, the 22nd, I noticed that the Antarctic ice cover anomaly has hopped from +1m km2, to zero in about two weeks. This shows how quickly things can change, and how extreme the variability is in polar regions. I suspect this means, though, that we are now at a new record low global ice anomaly…
Regards,
August 22, 2007 at 5:36 pm
Nick
Thanks for your reply. -2m km2 and counting
February 11, 2009 at 10:47 pm
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