Arctic ice cover is approaching the record low that was set by last year’s unprecedented rate of melting ice. The extent from this year compared to last year was very close through about mid-June. Weather patterns were different this summer than last summer and the rate of melting this summer lagged last year’s. The melt rate increased toward the end of July of this year, as the National Snow and Ice Data Center’s time series comparison graph shows. The rates were approximately equitable for the first couple weeks of August.
Comparing the extent as measured by satellite one week ago to today, take note of “fingers” of ice north of eastern Russia (northwest of Alaska). Two fingers developed quickly melting regions between themselves and the larger ice pack further north. Those fingers essentially disappeared in one weeks’ time. Additionally, the ice north of central Russia has melted, opening up ocean between Russia and the ice sheet. Lastly, the Northwest Passage is now nearly open for the second year in a row after holding out for much of July.
Looking at the two plots I’ve linked to above, I’m not sure last year’s record low areal extent is going to be maintained. The rate of melt in the past week or so is clearly greater than it was at this time last year. This condition was predicted by ice climatologists at the end of last summer. Since a great deal of long-term ice melted last year, it was easier this year for the ice to remelt since it was thinner and less stable. The arctic melt season typically lasts until mid-September. So there are about three more weeks for additional melting to occur. In fact, if you look at today’s ice extent (the right side of the 2nd plot above), note the extensive area of ice than has been measured to be less than 50% concentration (located to the south of the North Pole in the direction of Alaska and far eastern Russia). A considerable region of ice could still melt this year.
The situation in the Arctic is dire.
Update: The NSIDC released a different time series graph that the BBC (not American corporate media!) picked up. Up until a couple of weeks ago, 2008′s melt curve looked eerily like 2005′s, which was the 2nd lowest on record. As of a couple of weeks ago and every day since, 2008′s curve has solidly moved into 2nd, which isn’t a record we should be aiming for. More importantly, the fact that the three worst years on record are currently 2007, 2008 and 2005 signals a pattern that we should pay attention to. The question that we must face up to is the following: when will the Arctic be ice free? It doesn’t look like we’ll have to wait until 2080 or even 2030 anymore. It looks more and more likely that we’ll see it within 5 or so years!