Climate Feedback

Has Arctic summer sea ice tipped?

nrcc globe.jpg

For the long view on the 2008 Arctic sea ice melt, see today’s commentary on Nature Reports Climate Change by two National Snow and Ice Data Center researchers. Mark Serreze and Julienne Stroeve recap the results:

The seasonal minimum for 2008, occurring on 14 September, entered the books as the second-lowest of the satellite era, probably the second-lowest of at least a century, and just behind the standing record set in 2007.

Barely second-lowest still came as a shock, given the cooler weather this year. Said Stroeve in an NISDC press release, “I find it incredible that we came so close to beating the 2007 record — without the especially warm and clear conditions we saw last summer. I hate to think what 2008 might have looked like if weather patterns had set up in a more extreme way. ”

August 2008 saw the fastest melt ever recorded, according to NASA. And ice volume, a bellwether for the future, probably was at its lowest this year – an observation that hasn’t reached the broadsheets (but see Climate Progress and Stoat).

NSIDC scientist Walt Meier explains, “Warm ocean waters helped contribute to ice losses this year, pushing the already thin ice pack over the edge. In fact, preliminary data indicates that 2008 probably represents the lowest volume of Arctic sea ice on record, partly because less multiyear ice is surviving now, and the remaining ice is so thin.”

Yes, unlike you or me, Arctic sea ice is getting younger and thinner as the years pass. Old, thick ice that has survived through multiple summers – which two decades ago grew fast enough to roughly match the loss of Arctic ice into the North Atlantic – is giving way to flimsy young stuff that readily melts into open water during the warm months. The endpoint of this trajectory would be all-new ice in winter and no ice in summer. Serreze and Stroeve:

With sharply rising atmospheric greenhouse gas concentrations, the change to a seasonally ice-free Arctic Ocean seems inevitable. The only question is how fast we get there. The emerging view is that if we’re still waiting for the rapid slide towards this ice-free state, we won’t be waiting much longer.

Looking back at recent changes, the authors talk triggers. Models suggest that thinning Arctic sea ice is “vulnerable to a ‘kick’ from natural variability that sets the feedback process into high gear,” they note, resulting in “abrupt transition” to ice-free summers. The warmth of 2007, caused by an unusual atmospheric circulation pattern, is one of the candidates for a recent kick – and though this year brought a slight recovery of ice extent, signs point to more losses coming up.

Anna Barnett

Image: Sea ice on 14 September 2008, the date of the minimum. Courtesy of National Snow and Ice Data Center.


  1. Report this comment

    William E. Marks said:

    Man induced climate change and melting ice caps and glaciers is indicative of how our species has altered the evolution of our biosphere.

    The onset of human evolution and our growing power to transform our planet is now a pressing issue. For we have arrived at a time when our knowledge is informing us as to how our behavior directly influences the condition of our Earth’s responsive Biosphere.

    Slowly, we are awakening to the reality that the next step in our evolution is to act with knowledge. To act in a responsible fashion so we may survive as a species, with the help of other species – within the limited energy support system provided by our Biosphere.

    And, most importantly, to understand and work with the creative and destructive energies of water – for water is the key to determining the future of all life forms.

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    Steven Earl Salmony said:

    The global economy is saved, now how about turning attention and financial resources to saving the Earth from a meltdown?

    It looks as if the Wonder Boys on Wall Street, who caused the current disaster in the world’s financial system, are going to rescue the family of humanity from a meltdown of the global economy.

    Is it too much to ask some of these multi-billionaires to provide wealth to save the world from the global “meltdown” of Earth’s ice pack that is occurring in Greenland, Antarctica, the high mountain ranges from the Arctic Cordillera, to the Andes to the Himalayas?

    Steven Earl Salmony

    AWAREness Campaign on The Human Population,

    established 2001

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    R James said:

    Steve Salmony – you need to check your facts. Antarctic ice reached it’s highest coverage for at least 30 years last month. Arctic ice is currently about 25% up on last year at this time, and is above 2005 levels. There’s been no global warming for the past 10 years – even the 11 year trend has turned downward.

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    Stuart Harmon said:

    Dear Anna

    From your article you state

    " the fastest sea melt ever recorded" and “lowest volume of sea ice on record”

    Do you not think that professionally it would be correct to add "although it should be noted that records are only available for the last 10? 20? 30? years.

    Wrap up warm its getting Colder and has been for the last ten thousand years.

    Best Regards

    Staurt Harmon

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