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Arctic ice in uncharted territory

  1. Sep 20, 2012 #1

    apeiron

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  2. jcsd
  3. Sep 20, 2012 #2
  4. Sep 20, 2012 #3

    phyzguy

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    I like this site. It has maps and graphs of the ice extent and in both the arctic and antarctic.
     
  5. Sep 20, 2012 #4
  6. Sep 20, 2012 #5
    Anyone think small populations of polar bears could adapt and survive in northern greenland/canada if summer ice is scarce?
     
  7. Sep 20, 2012 #6

    turbo

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    Tough call. There aren't a lot of tasty seals on dry land, for one thing. Could they pick up a new food source that is high enough in fat to sustain them?
     
  8. Sep 20, 2012 #7
    Maybe we should have some references of research in the past instead. First of all, the polar bears have been around over 100,000 years (http://www.nature.com/nature/journal/v446/n7133/full/446250a.html) and it was almost certain that there was virtually little or no sea ice in the Arctic somewhere between 10,000 and 9000 years ago (Baumann and Matthiessen 1992, MacDonald et al 2007, Jessen et al 2010). Yet, the bears are still here.

    which also shows that the Antarctic ice is hovering around a bit of a maximum

    http://arctic.atmos.uiuc.edu/cryosphere/antarctic.sea.ice.interactive.html
     
    Last edited by a moderator: May 6, 2017
  9. Sep 20, 2012 #8
    This is hardly an unprecidented loss of sea ice. A thousand years ago the Vikings sailed the Artic pretty much unencumbered by ice. They gave Greenland its name because of its lush green pastor land. Then everything froze up and they abandoned that island. For the next 500 years everyone called it the little ice age, until recently when things began to warm up we started calling it global warming. Well, warming is what you expect when we come out of an ice age to re-establish what was normal several centuries ago.
     
  10. Sep 20, 2012 #9
    This NOAA set of graphs suggests we have reached and are about to surpass the temperatures of the Medieval Warm Period in the northern hemisphere, at least as far back as 800 CE. However, there is enough ice cover left from the Little Ice Age so that we probably have more perennial ice right now than during the maximum of the Medieval Warm Period.

    http://www.ncdc.noaa.gov/paleo/globalwarming/medieval.html

    I think the next few years will be critical in determining whether this trend stabilizes or not, based on these graphs.
     
    Last edited: Sep 20, 2012
  11. Sep 20, 2012 #10
    SW: Thanks. That is good to know.
     
  12. Sep 24, 2012 #11
    It appears that this NASA clip may be useful in this discussion.

     
    Last edited: Sep 24, 2012
  13. Sep 24, 2012 #12
    Interesting. I don't recall this being mentioned in broadcast discussions of the loss of Arctic sea ice cover. However, there has been a steady decline in multi-year sea ice over the past decade. The older thicker ice is more resistant to storms. Right now, winter re-freezing will leave about 2/3 of the Arctic Ocean with single year ice when the sea ice area reaches its maximum.
     
  14. Sep 24, 2012 #13

    apeiron

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    Yes, NSIDC comments.....

    It seems a reasonable comment that it is total ice volume rather than simply ice extent which is critical here. So ice may have continued thinning at a steady rate since the last record melt in 2007, which is what makes it more prone to mechanical break up and an apparent more abrupt lurch in one year.

    [EDIT: I see SW VandeCarr beat me to it on that point.]
     
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