Tag: sea ice

A beginner’s guide to the importance of Arctic sea ice

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In this beginner’s guide Tom Wagner, NASA’s cryosphere programme manager, outlines why studying Arctic sea ice is important, illustrating his talk with some great graphics. Meanwhile, the NSIDC has announced the final figures for September’s sea ice minimum:

The average ice extent over the month of September, a reference comparison for climate studies, was 5.36 million square kilometers (2.07 million square miles). This was 1.06 million square kilometers (409,000 square miles) greater than the record low for the month in 2007, and 690,000 square kilometers (266,000 square miles) greater than the second-lowest extent in 2008. However, ice extent was still 1.68 million square kilometers (649,000 square miles) below the 1979 to 2000 September average.

NSIDC scientist Walt Meier thinks there may be some hope of “stabilising” the ice after recent heavy losses:

We’ve preserved a fair amount of first-year ice and second-year ice after this summer compared to the past couple of years. If this ice remains in the Arctic through the winter, it will thicken, which gives some hope of stabilizing the ice cover over the next few years. However, the ice is still much younger and thinner than it was in the 1980s, leaving it vulnerable to melt during the summer.

But will there be a longer term recovery back towards the sort of ice cover seen before 2000? The NSIDC team doesn’t think so.

NSIDC lead scientist Ted Scambos said, “A lot of people are going to look at that graph of ice extent and think that we’ve turned the corner on climate change. But the underlying conditions are still very worrisome.”

After a couple of cool summers, one wonders what impact another warm year might do to the ice. As ever, I shall be watching next year with great interest…

Arctic takes a Turney for the worse

British geologist Chris Turney is just back from fieldwork in Svalbard, the island archipelago situated halfway between Norway and the North Pole. He has written about it in his popular science blog, under the title A Warning From the North. I’ll draw attention to some of his main points here, but first a reminder that he is the author of Ice, Mud and Blood which I reviewed on Hot Topic early this year. He’s also a director of New Zealand company Carbonscape which Hot Topic has featured more than once.

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Third

The National Snow and Ice Data Centre announced today that this year’s Arctic sea ice minimum extent was likely to have been reached on September 12. It’s the third lowest minimum in the record, behind 2007 and 2008. The image at left shows this year in white, compared with 2007 in darker colours. From the report:

On September 12, 2009 sea ice extent dropped to 5.10 million square kilometers (1.97 million square miles). This appears to have been the lowest point of the year, as sea ice has now begun its annual cycle of growth in response to autumn cooling. The 2009 minimum is the third-lowest recorded since 1979, 580,000 square kilometers (220,000 square miles) above 2008 and 970,000 square kilometers (370,000 square miles) above the record low in 2007. The 2009 minimum is 1.61 million square kilometers (620,000 square miles) below the 1979 to 2000 average minimum and 1.28 million square kilometers (490,000 square miles) below the thirty-year 1979 to 2008 average minimum.

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This NSIDC graph gives a very good idea of what’s been happening this year. 2009 has never looked much like beating 2007, but until mid-August it was giving 2008 a run for its money. However, a relatively cool summer and winds during August that dispersed the ice held the minimum extent above last year.

[Update 19/9] NASA’s Earth Observatory posts this graphic of the ice distribution on 12/9:

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The usual suspects will no doubt trumpet this as a “recovery”, but the NSIDC team don’t think so:

Continue reading “Third”

(Arctic) Change is now

The World Wide Fund for Nature (WWF) has just published a new report on climate change in the Arctic — Arctic Climate Feedbacks: Global Implications [PDF], and it’s a fascinating read. Over the last two years I’ve blogged regularly on the changes being seen in the Arctic — sea ice reductions, melting of the Greenland ice sheet, the danger of increased carbon release from permafrost and sea floor methane hydrates, and the possible impacts on northern hemisphere weather patterns and climate. WWF’s report — written by some of the leading names in the field (including Serreze, Stroeve, Cazenave, Rignot, Canadell, and for the methane hydrate chapter Shakhova and Semiletov) — pulls together all those strands to paint a picture of a region undergoing rapid change. The authors provide a fully-referenced review of our current understanding of the processes at work as the pole warms, with chapters covering atmospheric circulation feedbacks, ocean circulation changes, ice sheets and sea level, marine and land carbon cycle feedbacks, and sea floor methane hydrates. It’s compelling stuff, and well worth reading in full, but for this post I want to focus on the excellent overview of methane hydrate feedbacks provided by Natalia Shakhova and Igor Semiletov.

Continue reading “(Arctic) Change is now”

Start me up

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Above: a new animation of Arctic sea ice from 2000 to May 2009, from the Alfred Wegener Institute for Polar and Marine Research and KlimaCampus of the University of Hamburg in Germany. It accompanies their first contribution to this year’s sea ice forecasts — and they put the odds of a new record minimum at either 28%, or with an enhanced model that takes better account of current ice conditions about 49%. Close enough to my gut feeling of 50/50 to allow me a little confirmation bias, I think… The press release is here, and the full forecast here (pdf). The AWI modelling is part of the Search forecasting exercise I mentioned last week. The full set of forecasts should be out in the next week to ten days, according to project co-ordinator Jim Overland, and I’ll cover them when they become available.

[The Folksmen]