It's that time of year again -- the time when ice researchers gather round the latest satellite data from the Arctic, and probably drown their sorrows in a stiff drink or three.
Last year was major cause for alarm -- sea ice coverage was at its lowest ever in the summer of 2007. That pushed up a lot of projections for an ice-free Arctic from 2050 or so to as soon as ten years from now.
"But there's a lot of variability in the climate system, and it's possible 2007 was an anomaly" some might say. True enough, but things are looking bleak again this year -- the latest data are in, and 2008 just past 2005 for the second-smallest ice coverage on record. Bummer.
According to the latest from the National Snow and Ice Data Center, the sea ice extent was down to 5.26 million square kilometers (2.03 million sq miles) as of yesterday, August 26.
That's down 2.06 million sq kilometers (795,000 sq miles) since the beginning of the month, but it's not the worrying bit. The worrying bit is that the ice is probably not done melting yet. In 2005 the ice minimum didn't occur until September 21. As you can see from the graph below, it's pretty typical for sea ice to take until then to start refreezing.
This preliminary measurement is missing one key piece of context, though -- how much of the ice being lost is perennial sea ice? 
Ice that makes it through the summer without melting is thicker and shows up differently on satellite images, so researchers should be able to figure out how much was lost compared to last year.
Of course since 2007 was the worst year ever (unless the ice melts another 430,000 sq kilometers in the next month) it's possible that this year will register something of a gain in perennial ice.
If there is, it won't make headlines because the gain won't be big or very meaningful. The individual years don't matter so much -- it's really the trend that they describe that we should care about. Looking at the NSIDC's graph I think it's plain: an ice-free Arctic Ocean is on its way. It's just a matter of time, and not much, either.
Note: in case it's hard to read the graph, the black line at the top is the 1979-200 average sea ice extent. Gray is 2005, green dashed is 2007, and the bright blue is 2008.
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