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Global warming makes bears sweat
03/11/2002 15:37 - (SA)
Guy Clavel
Churchill, Canada - Polar bears that roam the Hudson Bay area in the great Canadian
north are impatiently waiting for ice to form, and as the winter
shortens year by year their lives are becoming increasingly
threatened.
"Over the last 20 years, the ice breaks an average of two weeks
earlier," said Michael Goodyear, director of the Churchill Northern
Studies Centre.
The giant white bears need the ice to gain access to ringed and
barbed seals which live and play away from land among the ice
bergs.
"For every week a bear has not been ice hunting, it is 10
kilogrammes lighter, which can be dangerous as polar
bears need to fatten up for the five months in the summer and fall," Goodyear said.
The thousand or more polar bear families of the Hudson Bay area
are in great danger if, as Goodyear believes, ice disappears from
the area by 2050.
"Churchill is one of the best places I see climate change as so
important," he said.
The average temperature has risen from 0.3 to 0.4 degrees
Celsius since 1950. According to the Canadian Wildlife Service the bears, on average, already
weigh between 80 and 85 kilogrammes less than
they did in 1985.
Goodyear's alarm echoes those of many specialists in the past
few years. Ian Stirling is one of the Canadian Wildlife Service's
Arctic experts.
In an article for Arctic Magazine three years ago he noted that
between 1981 and 1998 the physical condition of both male and
female adult bears had seriously deteriorated in populations of
western Hudson Bay, in tandem with a general reduction in their
numbers.
According to Stirling, the immediate cause of this decline was
an increasingly early melt, leading the bears to come ashore in
weaker and weaker states.
And, he added, the source of the shortened ice season appeared
to be the effect of long-term gradual warming in the spring.
"Polar bears in Hudson Bay are being impacted by climate
change", said Lynn Rosentrater, co-author of the World Wildlife
Fund's report Polar Bears at Risk.
"As sea ice is being reduced in the area, the polar bear's basis
for survival is being threatened. The sea ice is melting earlier in
the spring which is sending polar bears to land earlier without
them having developed as much fat reserves for the ice free
season," said Rosentrater, who is also the climate change officer
at the fund's Arctic Programme.
"By the end of the summer they are skinny bears, which in the
worst case can affect their ability to reproduce."
In an article in Science Magazine from August Richard Kerr
reported: "In western Hudson Bay, where warmer temperatures in the
1990s made for earlier ice melting in the spring and later
formation in the fall, polar bears have suffered."
The bears' situation has been declining since 1992 when the ice
field formed three weeks late due to a temperature rise of two
degrees Celsius.
The eruption of Mount Pinatubo in the Philippines in 1991
coupled with El Nino led to a drop in the bears' birth rate, which
had been on the rise.
"The extent of Arctic ice has shrunk 5% in the past 20
years, its thickness is down, and climate models forecast continued
shrinkage as global temperatures climb," said Kerr.
As ice during the summer retreats farther and farther northward,
the open water so alluring to commercial interests will confound
polar bears looking for solid footing in their hunt for seals.
"Inuits and other indigenous peoples likewise depend on the ice
for access to whales and walruses. An algae at the base of the food
pyramid cling to the underside of the ice," Kerr said.
"A hundred years from now, life around the Arctic Ocean will go
on - but it will not be the same," he added. - Sapa-AFP
- SAPA
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