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View Diary: Rapid melt spreads to NW Greenland, 400ppm CO2 may melt cap (226 comments)

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  •  What is the timeline in your model? (3+ / 0-)

    It took over a thousand years for the Great Lakes lobes of the Laurentide ice sheet to melt, during much warmer temperatures than present day Greenland's, with a sea just as warm buffered against them (the Champlain sea.)

    If apes evolved from humans, why are there still humans?

    by Bobs Telecaster on Fri Mar 26, 2010 at 04:17:13 AM PDT

    •  Bob ... (4+ / 0-)

      I think FooW might be asleep right now...I'm taking a look at the paper quickly to see if I can find that out.

      Bill

      When will we ever learn that PROFIT cannot be a part of the equation when endangering people's lives adds to a company's bottom line?--Earicicle

      by billlaurelMD on Fri Mar 26, 2010 at 06:01:51 AM PDT

      [ Parent ]

      •  From page 257 of the article (pdf page 25) (4+ / 0-)

        "These simulations were run for time-integrations of 400 model years."

        So they got their new ice equilibrium in 400 years.  The time series of ice loss (and water added to the oceans) would be interesting to see.

        Another interesting item in the discussion toward the end (pdf pp 29-30):

        Current ice-sheet models lack higher-order physics, and although able to simulate slow moving ice dynamics adequately, they are not yet able to represent the dynamics of fast-moving ice streams. Recent work has indicated that current loss of mass from the GrIS is roughly equally partitioned between surface mass balance changes and changes in dynamics (Van den Broeke et al., 2009). Development of ice-sheet models in these areas is currently being researched with improvements to ice dynamics (e.g. Soucek and Martinec, 2008; Pattyn, 2003), and inclusion of accurate representation of the fast ice streams and ice shelves (Pattyn et al., 2006; Schoof, 2006, 2007). Recent observations of glaciers on Greenland have documented rapid changes in marginal 5 regions of the ice-sheet with increased flow velocities observed on Jakobshavn Glacier (Joughin et al., 2004) and on other glaciers (e.g. Howat et al., 2007; Rignot and Kanagaratnam, 2006). The inclusion of these fast flowing ice streams in ice-sheet models could lead to larger dynamical changes in the ice-sheet than currently predicted by models at least on relatively short timescales of hundreds of years.

        That is, the models don't include fast moving rivers of ice YET (ever seen that movie of a Greenland glacier showing the loss of 0.5-1 km worth of a glacier in what I think is a day?). Once they do, well, these slow process ice-sheet models may be rendered moot with their slowness.

        When will we ever learn that PROFIT cannot be a part of the equation when endangering people's lives adds to a company's bottom line?--Earicicle

        by billlaurelMD on Fri Mar 26, 2010 at 06:15:03 AM PDT

        [ Parent ]

        •  Excellent highlight, thanks. (0+ / 0-)

          All the ice models are being upgraded to reflect recent data showing faster movement.

          look for my DK Greenroots diary series Thursday evening. "It's the planet, stupid."

          by FishOutofWater on Fri Mar 26, 2010 at 10:51:23 AM PDT

          [ Parent ]

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