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Climate Hustle

Graphics for Sea Ice Minimum 2011

Posted on 6 October 2011 by Peter Hogarth

Arctic Ice: The Canary in the Coal Mine?  A brief introduction

Arctic ice extent and volume over the satellite record since 1979.

Whilst some have argued at various points over the past few years that sea ice is recovering after the dramatic 2007 Summer sea ice losses, the reality is that both extent and overall volume are on an increasingly downwards multi-decadal trend, as older ice is lost and what little perennial ice that remains is thinning. Data from NSIDC (National Snow and Ice Data Centre)and PIOMAS (Pan-Arctic Ice-Ocean Modeling and Assimilation System). Uncertainties in NSIDC SSMI ice extent are around +/- 50 x 103 km2 whilst conservative estimate of uncertainties in PIOMAS volume are +/- 1.35 x 103 km3.

The Summer 2011 sea ice extent minimum was very close to, or had even dropped below (depending on which sensor and processing method is used) the 2007 record value. The minimum levels for the past five years are the lowest five in the record to date. The annual average Arctic extent value is also tracking very close to the previous minimum value in 2007, and may yet drop further this year. The 2011 Arctic ice volume (both the Summer minimum and annual average), are estimated to be at record low levels, the average volume having dropped by 45% over the past 33 years. Accounting for the uncertainty levels, there is currently less Arctic sea ice than at any time in the records, and the scientific consensus is that this downwards trend will continue for the foreseeable future.

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Comments 1 to 8:

  1. The 365-day anomaly graph would be very cool to see displayed on a map where the number of days of ice cover on a given map point would be color coded.
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  2. Suggested reading:

    "Climate change eradicating Arctic's oldest ice," The Vancouver Sun, Oct 5, 2011

    To access this article, click here
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  3. Suggested reading:

    “Arctic Sea Ice Continues Decline, Hits Second-Lowest Level,” Science Daily, Oct 4, 2011

    To access this article, click here
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  4. Young and thin instead of old and bulky is Science Daily's report from the return of the Polarstern after its summer expedition.

    Basically, the central Arctic is now covered in thin, 1 year-old floes. They found bulky multiyear ice only in the Canadian Basin and the Severnaya Zemlya areas had any of the 2-5 metre thick ice.

    We'll probably have to wait a fair while for any papers or detailed analyses.
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  5. NASA videos here.
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  6. The 2 most recent items at are worth a good look.

    The animation of 23 years of the Beaufort gyre is fan-tas-tic and the commentary raises some issues in a new light.

    The one on ice thickness and how to calculate it from ice freeboard is also handy.
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  7. On september 22 the Platform Communication on Climate Change posted a (Dutch) message on this topic on their website
    I wrote this message (as an employee of the Netherlands Environmental Assessment Agency, PBL). I also reported the decline in volume, but I could not find the value of the uncertainty range. The message above indicates it is 1.35 m3 km. Where can I find this number on the PIOMAS website and what it the meaning of this interval? (one sigma, 2 sigma?)
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  8. Suggested reading:

    “Young and Thin Instead of Old and Bulky: Researchers Report On Changes in Arctic Sea Ice After Return of Research Vessel Polarstern” ScienceDaily, Oct 6, 2011

    To access this article, click here
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