Tumblr Icon RSS Icon

What drove the dramatic retreat of arctic sea ice during summer 2007?

By Joe Romm

"What drove the dramatic retreat of arctic sea ice during summer 2007?"

Share:

google plus icon

arctic-9-07.gif

Funny you should ask. That is the title of an analysis published this month in Geophysical Research Letters (subs. req’d) by four scientists from the Polar Science Center, Applied Physics Laboratory, College of Ocean and Fishery Sciences, University of Washington, Seattle. What did they conclude?

A model study has been conducted of the unprecedented retreat of arctic sea ice in the summer of 2007. It is found that preconditioning, anomalous winds, and ice-albedo feedback are mainly responsible for the retreat. Arctic sea ice in 2007 was preconditioned to radical changes after years of shrinking and thinning in a warm climate. During summer 2007 atmospheric changes strengthened the transpolar drift of sea ice, causing more ice to move out of the Pacific sector and the central Arctic Ocean where the reduction in ice thickness due to ice advection is up to 1.5 m more than usual. Some of the ice exited Fram Strait and some piled up in part of the Canada Basin and along the coast of northern Greenland, leaving behind an unusually large area of thin ice and open water. Thin ice and open water allow more surface solar heating because of a much reduced surface albedo, leading to amplified ice melting. The Arctic Ocean lost additional 10% of its total ice mass in which 70% is due directly to the amplified melting and 30% to the unusual ice advection, causing the unprecedented ice retreat. Arctic sea ice has entered a state of being particularly vulnerable to anomalous atmospheric forcing.

In short, Santa Claus and Superman need to find a new home. Next stop for them — East Antarctica, which is probably good for another century or two.

Related Posts:

Tags:

‹ UPDATED WITH POST-MORTEM — Climate Progress on Fox News at 3:55 pm EST …

No Anonymous Comments ›

14 Responses to What drove the dramatic retreat of arctic sea ice during summer 2007?

  1. Earl Killian says:

    Antarctica may be next on the hit list. Did you see this?:
    http://www.sciencemag.org/cgi/content/full/sci;320/5882/1486

  2. simp says:

    outch… really looks like we need to hurry up!!

  3. Paul K says:

    simp,
    We use real names or links to our own websites here.

  4. Paul K says:

    I don’t have a subscription. The excerpt does not mention CO2 or AGW. Are there some quotes in the actual article? The excerpt repeats my previous comment exactly. The ice melt is caused by preconditioning – decadal ocean oscillation, albido – fine soot, and advection – fortuitous winds.

  5. Joe says:

    Paul — we apparently read a different abstract:
    “Arctic sea ice in 2007 was preconditioned to radical changes after years of shrinking and thinning in a warm climate.”

  6. Paul K says:

    Joe,
    Yes and NASA scientists, in studies specific to recent arctic melting, found the cause of the arctic warm climate to be oscillations. That’s the fact.

  7. Mauri Pelto says:

    Preconditioning from years of warmth. Where have I read-written the same words. Oh, yeah with respect to the loss of ice shelves in Antarctica. Oh, and with the loss of several glaciers in the North Cascades. http://www.nichols.edu/departments/Glacier/deathglacier.htm. This is the chorus line for losing ice. Preconiditioning from years of warmth.

  8. Paul K says:

    There’s an inadvertent extra “.” in Mario’s link. This should work.

  9. llewelly says:

    Next stop for them — East Antarctica, which is probably good for another century or two.

    Do you really think the East Antarctic Ice Sheet is likely to melt substantially (say, more than 10%) within the next 200 years? If so, why?

  10. john says:

    I won’t speak for Joe, but I believe it is likely. Why? Because if we don’t act to halt carbon emissions and ultimately reduce atmospheric concentrations to less than 350 ppm, we face a number of nasty feedback loops which will cause the atmosphere to heat and the ice to melt.

    This has happened twice before (at least — both were due to extreme volcanic activity causing emissions comparable to what humans are causing now (albeit the volcanic emissions occurred at a much slower rate than we are now emitting).

    Examine what happened in the PETM and in the Permian die-off. If you keep an open mind that should convince you it’s at least likely, if not inevitable at this point.

  11. Joe says:

    If we go to 1000 ppm, as now seems likely, the East Antarctic Ice Sheet can’t possibly survive. If we warm another 3°C, then the planet will be warmer than it was last time we were ice free, including no EAIS. We are headed to warming perhaps another 5°C — or more. So we will probably lose much of Greenland and WAIS and a good chunk of EAIS over the next 200 years.

  12. David B. Benson says:

    There is no enough study of the Miocene Antarctic melt. At least I don’t know much of anything about it.

  13. llewelly says:

    john:

    Examine what happened in the PETM and in the Permian die-off. If you keep an open mind that should convince you it’s at least likely, if not inevitable at this point.

    How long did the PETM take to happen? How long did the P-T warming take? I have read 10,000 years for the former, and similar figures for the latter. The carbon-cycle positive feedbacks and methane releases theorized to explain those warmings took time to do their work – probably a lot more time than 200 years. In any case, I think you’ve answered my question – substantial melt of EAIS in less than 200 years appears to require either positive carbon-cycle feedbacks, methane gas releases, or massive human emissions, at or exceeding the worst of the IPCC scenarios. (I will grant that positive carbon-cycle feedbacks are looking more and more likely. I will also grant that widespread coal-to-liquids could put human emissions at or exceeding the worst of the IPCC scenarios.)