Eli Rabett, that ever-curious but lovable lagomorph, has noticed the appearance of an apparent annual cycle in the Arctic sea ice area anomaly chart at the excellent Cryosphere Today. I mentioned the same thing in a post on Arctic sea ice back in April, and hinted that I might look at it “another day”. Well, that day has come, not least because the ice “experts” at ÂµWatts have been suggesting it might be a satellite problem (it isn’t).
The usual suspects have been making much of the fact that over the last few weeks Arctic sea ice extent (NSIDC daily graph here) has been bumping around the 30 year average for this time of year. John Cook at Skeptical Science posted on the subject last weekend, making the important point that what matters most is not extent or area, but the total volume of ice that’s present — and that’s showing no signs of “recovery”. John’s post is well worth reading, but it set me off on a very interesting trawl through the references he provided — and drew my attention to a most useful graph of ice volume and trend. It also pointed me to research that suggests the Arctic could be effectively ice-free in summer within ten years — possibly as soon as 2013.