The extent of sea ice is not all that matters
Posted on the 01.09.2010 by Alain Hubert
Every now and again, I would like to draw our readers’ attention to a particular item of polar topicality. Today, I would like to zoom in on an article written by Chris Mooney. He points out that the reduction of the Arctic pack ice surface is not the only problem caused by global warming. There are also drastic changes to its thickness and its quality.
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Once upon a time
Most of my polar adventurer/explorer colleagues agree with me (you just have to read the blogs that they write during their expeditions); the Arctic pack ice is no longer what it was. On 20 April 2007, during my crossing of the Arctic Ocean (see the update at the time), I remember having written – even though we were barely 80 kilometres from the North Pole - that we were in a real ice bog, like mud consisting of interstitial waters and all kinds of increasingly rotten sorts of ice. Normally at such latitudes we were used to meeting old ice - thick, solid and really stable.
No Problem In Cutting A Path Through It
You’ve already understood that it is the loss of quality of the Arctic pack ice that I would like to bring to your attention today. An article that I’ve discovered has led to my writing these few lines. It was written by the American journalist specialising in science and politics, Christopher Cole Mooney, and was published on the New Scientist Environment website on 31 August last. What can be found in it? After having discovered that the melting of the Arctic pack ice is due not only to global warming but also to a weather phenomenon called Arctic Dipole (a high pressure area over the Beaufort Sea opposite a low pressure area over the north of Siberia), we learn that there is as yet no reliable mathematical model for measuring the total volume - not just the surface - of the pack ice. Mooney writes: "There is no long-term record of the total volume of ice because we have only patchy data; ICESat was launched in 2003 and failed earlier this year. The nearest thing we have are estimates from PIOMAS, developed by Jinlun Zhang and his colleagues at the University of Washington's Polar Science Center in Seattle. Actual satellite measurements of sea ice concentration since 1978 are fed into a computer model of the growth, melting and motion of sea ice to produce an estimate of ice volume. PIOMAS's results correspond well with independent measurements by submarines and by ICESat. According to PIOMAS estimates supplied to New Scientist by Zhang, the average volume of Arctic ice between July and September has fallen from 21,000 cubic kilometres in 1979 to 8000 cubic kilometres in 2009. That is a 55 per cent fall compared with the 1979 to 2000 average. "The loss of ice volume is faster than the loss of ice extent," says Zhang. His model suggests that not only has the total volume of Arctic ice continued to decline since 2007, but that the rate of loss is accelerating".
A Researcher Woke Up One Morning…
Admittedly, this discovery is not recent. But it has been revived by a Canadian scientist from the University of Manitoba in Winnipeg, David Barber, when he was sent on an assignment in the Arctic waters in September 2009. He was on board the CCGS Amundsen and realised one day as he awoke that whereas the ship was at a latitude where normally the ice-breakers find it hard to get through, the CCGS Amundsen research ship was not having any such problem. And it was briskly sailing full steam ahead
Questions and Consequences.
The writer asks himself the questions that everyone is asking. When will the Arctic Ocean be ice-free? Mooney : "What it all means is that, much like the Amundsen, we are now cruising effortlessly into a world that may soon feature an essentially ice-free Arctic during at least part of the year. “Thirty years from now, maybe even 20 years from now, if you were to look at the Arctic from space you would see a blue ocean [in summer],” says Serreze." (Editor’s note; a researcher from the US National Snow and Ice Data Center based in Boulder, Colorado).
Of course, a major part of this article is devoted to the consequences of what could become a new element to be taken into account in the phenomenon of the melting of the Arctic pack ice. For the Arctic’s bordering populations, for our planet’s global climate, for the economic activities that would ensue (strong increase of the sea traffic in this area with the obvious risks incurred), for the polar fauna and flora polar, for the moderate latitude regions, and so on and so forth.
In short, for those of you who are interested in these problems, I would strongly recommend that you to read this article.
The website where this article has been published.
CCGS Amundsen Sailing too easily through the Arctic ice pack
© Paul Nicklen/National Geographic/Getty
