I
asked the question about the status of polar bears in the Arctic
given the polar ice melt and that polar bears were the mascots for
the movement a few years ago.
This
was the reply I got from Gulo Gulo, who lives in northern Alaska -
“They
are afraid to - polar bear scientists are put under house arrest....
“I
was not kdding about scientists (being) fearful these days,especially in
Canada And of course many are funded by Big Oil. ….
Polar
Bears & Sea Ice
Related
video: Four
Sea Ice Eco-regions
Polar
bears need a platform of sea ice to reach the prey that sustains
them: ringed and bearded seals. But not
all sea ice is equal:
some sea ice lies over more productive hunting areas—and some ice
regions will melt sooner than others in a warming Arctic.
Scientists
have identified 19
populations of polar bears living
in four
different ice regions in
the Arctic.
Why
does it help to divide the Arctic into ice regions? For those polar
bear populations that are little-studied, scientists can
make informed
estimates on
how they're faring based on the health and condition of other
populations in the same region.
Four
Sea Ice Eco-regions
1.
Seasonal Ice Eco-region –
Seasonal ice areas occur at the southern
extreme of
the polar bear's range and include places like Canada's Hudson Bay,
where the ice melts each summer and the bears must wait for freeze-up
in the fall until they can hunt again. Polar
bears in these seasonal areas are the most endangered, with longer
and longer ice-free seasons testing the limits of their fat reserves.
2.
Polar Bear Divergent Ice Eco-region –
In these areas, sea ice forms along the shore but then retreats,
especially in summer. As the sea retreats farther and farther from
shore in a warming Arctic, these polar bears are faced with a choice
of coming ashore—fasting until the ice returns in the fall—or
swimming long, exhausting distances to reach the remaining pack ice.
Ice that's located far offshore, however, often covers unproductive
parts of the sea,
so bears in these areas may successfully complete a marathon swim,
but still not find any seals to hunt. Polar
bears that live in these areas are at great risk: from longer and
longer swims, prolonged fasting periods, and encounters with humans
on shore.
3.
Polar Basin Convergent Ice Eco-Region –
Sea ice formed in other parts of the Arctic collects
along the shore of
these habitats, providing polar bears with access to seals. Polar
bears in these areas are faring well now, but scientists predict that
ice in these areas will disappear within 75 years—and, with it,
resident polar bear populations—unless action is taken to reduce
CO2.
4.
Archipelago Ice Eco-region –
Islands in the Canadian High Arctic and Greenland are far enough
north that sea ice remains along the coast even in summer, providing
hunting for the bears. This
eco-region is predicted to be thelast
stronghold for
polar bears, but it, too, is expected to melt within 100 years unless
greenhouse gas emissions are greatly reduced.
Polar
Bear Population Distribution by Sea Ice Eco-region
Eco-region
1: Baffin
Bay, Davis Strait, Foxe Basin, Southern Hudson Bay, Western Hudson
BayEco-region
2: Barents
Sea, Chukchi Sea, Kara Sea, Laptev Sea, Southern Beaufort
SeaEco-region
3: Eastern
Greenland, Northern Beaufort Sea, Queen Elizabeth IslandsEco-egion
4: Gult
of Boothia, Kane Basin, Lancaster Sound, M'Clintock Channel,
Norwegian Bay, Viscount Melville Sound
Citation:
Amstrup, S.C., Marcot, B. G., and Douglas, David C. 2008. A Bayesian
Network Modeling Approach to Forecasting the 21st Century Worldwide
Status of Polar Bears. Pages 213-268. In Eric T. DeWeaver, Cecilia M.
Bitz, and L.-Bruno Tremblay Eds. Arctic Sea Ice Decline:
Observations, Projections, Mechanisms, and Implications. Geophysical
Monograph 180. American Geophysical Union, Washington, DC.
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