From AP (via CNN): “The Arctic is often cited as the canary in the coal mine for climate warming,” said Zwally, who as a teenager hauled coal. “Now as a sign of climate warming, the canary has died. It is time to start getting out of the coal mines.” The annual American Geophysical Union meeting in San Francisco is bringing bad news about the Arctic – most of it listed in the foregoing linked article. One paragraph is particularly shocking:
Still to be released is NASA data showing the remaining Arctic sea ice to be unusually thin, another record. That makes it more likely to melt in future summers. Combining the shrinking area covered by sea ice with the new thinness of the remaining ice, scientists calculate that the overall volume of ice is half of 2004’s total.
In three years, half of the summer ice has gone. In Hot Topic I suggest that it might all be gone in my lifetime – and I thought I was being pretty daring, given that the IPCC talks about the end of the century. One ice modeller who has been predicting an early demise for the summer sea ice is the US Navy’s Wieslaw Maslowski. From the BBC:
“Our projection of 2013 for the removal of ice in summer is not accounting for the last two minima, in 2005 and 2007,” the researcher from the Naval Postgraduate School, Monterey, California, explained to the BBC. “So given that fact, you can argue that may be our projection of 2013 is already too conservative.”
RealClimate is providing coverage of AGU highlights (here, here, here and (update – sea ice specific) here. The Herald runs with a very US-angled Reuters story. As I’ve pointed out before, the consequences of the loss of summer sea ice in the Arctic for northern hemisphere climate is not known, but I would expect that there’s some urgent work being done to find out. We’re into the land of the unknown unknowns, and there’s nothing we can do to stop it.
Gareth, have you seen any figures for the actual mass of the Arctic sea ice & how many cubic Km melt each year? That melt must take a lot of energy out of the environment each summer, if there’s much less there to melt and the melt is shifted to land ice, would that significantly accelerate the greenland melt?
I haven’t got the figures, I’m afraid, but if you follow the RC links, you can probably work out who to Google(Scholar). I have occasionally wondered if the reason the global average hasn’t increased much over the last few years is because the heat’s going into melting ice… but I wouldn’t rely on (or publish) my back-of-a-PostItNote calculations.
The loss of summer sea ice is just one symptom of excess heat reaching the North Pole. Once the summer ice is gone, the winter ice will be in trouble, and a Greenland surrounded by rapidly warming seas will not be a good place to keep ice cold.
There has to be some urgent work going on to model the seasonal Arctic heat balance. Most current models underestimate what’s going on. One way or another, the warming Arctic Ocean is intimately linked with sea level rise. Two pigeons coming home to roost, too soon.
I did find this over at Rabett Run:
“The bottom line is that if you thought things were going to hell in a handbasket you were an optimist. (From the AP)
2007 shattered records for Arctic melt in the following ways:
• 552 billion tons of ice melted this summer from the Greenland ice sheet, according to preliminary satellite data to be released by NASA Wednesday. That’s 15 percent more than the annual average summer melt, beating 2005’s record.
• A record amount of surface ice was lost over Greenland this year, 12 percent more than the previous worst year, 2005, according to data the University of Colorado released Monday. That’s nearly quadruple the amount that melted just 15 years ago. It’s an amount of water that could cover Washington, D.C., a half-mile deep, researchers calculated.”
552 billion tonnes = 552 cubic kilometres, so if we do see Arctic summer ice disappearing 1000 cubic kilometre/yr lose from Greenland soon might be possible (saying that knowing how little value such a guess has 🙂 )
I wonder how long before we see annual changes in thermal energy content of the oceans, ice and atmosphere as the standard measure of GW rather than surface temperatures.