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Polar bears face up to warmer future

Bear in the grass (BBC)
Lack of food has made the bears lethargic

ARCTIC SEA ICE EXTENT - SEPTEMBER TREND, 1978-2005
Graph showing ice decline (NSIDC)
The straight line tracks a more than 8% decline per decade

A polar bear (BBC)
Hungry bears will head into town - and conflict with humans




Polar bears face up to warmer future

By Kevin Bishop
BBC News, Churchill


*On the shore of the Hudson Bay in Northern Canada, a huge male polar 
bear stretches and yawns, sniffs the air and rolls back onto his side to 
sleep. *

It is mid-November and bitterly cold. The sea wind blows through our 
protective coats and our fingers start to lose circulation. But 
ironically, what we are witnessing is climate warming in action.

Temperatures in western Hudson Bay have been steadily rising 0.3 to 0.4 
degrees every decade since 1950.

Scientists at the US space agency's (Nasa) Goddard Space Flight Center, 
who have been monitoring the sea-ice from satellite data, believe it 
could be retreating at a rate of up to 9% every 10 years.

Each autumn, polar bears in this part of Canada migrate north, heading 
for the sea-ice which begins to form about now and stays solid until 
late spring the following year.


	
ARCTIC SEA ICE EXTENT - SEPTEMBER TREND, 1978-2005
The straight line tracks a more than 8% decline per decade

By sniffing the air, the bears know when the temperature is dropping and 
the sea is beginning to freeze.

The bear, who has been named Echo by scientists, should by now be way 
out on the frozen waters hunting for seals.

He has not had a proper meal since the ice broke up in July. He is 
hungry and losing up to a kilogram in body fat every day.

For the past 30 years or so, people living in Canada's north have been 
noticing a phenomenon that many scientists now believe is a direct 
result of our planet warming up.

* Ice opportunity *

The waters of Hudson Bay - and many other northern seas - are beginning 
their annual freeze later each year.

This November, local residents are saying that the waters are up to a 
month late in freezing up. Similarly, in spring the ice is breaking up 
earlier.

The net result - polar bears have less time on the solid ice to hunt.

Bears can only catch seals on ice. Seals are mammals and therefore need 
to breathe oxygen.

To do this they use holes or cracks in the ice to come up and gasp in 
some air between bouts of swimming underwater.

They also shelter in small pockets of air just under the surface. Bears 
anticipate this and mainly catch their prey when they are up for air.

* Lazy days *

Dr Jane Waterman is a biologist from the University of Central Florida. 
She has been coming to the shores of Hudson Bay in Canada for several 
years now, primarily to study adult males' play-fight rituals.

She has noticed worrying trends in the condition and behaviour of the 
bears as the freeze gets later each year.

Watching through her binoculars as bears alternately play-fight then 
slump down to sleep, she tells me that the long summer fast means that 
by now the bears are starving.

The greater period of fasting means they don't have as much energy. They 
are surviving by chewing on strands of kelp and seaweed to keep their 
juices flowing; but they need to eat soon.

* Bin raid *

We are trundling through the mud and ice of the seashore in a so-called 
tundra buggy.

This huge contraption that towers above the land like some lunar 
explorer serves not only to negotiate the harsh and slippery terrain, 
but also to keep the scientists safe from the bears.

At times, inquisitive and hungry males approach the buggy, standing on 
their hind legs to get a closer look at us.

They appear healthy and in fact observers say that there is little to 
indicate that the long fast has had too detrimental an effect on them 
this year. But this is due to a good eating season this past spring.

The worry is whether they can adapt to successive years of shortened 
feeding periods on the ice.

* Bear traffic *

For the residents of the nearby town of Churchill this trend raises an 
additional concern. Manitoba Conservation warden Sean Bobier patrols the 
town and its shoreline outskirts, protecting the residents from bear 
attacks.

As they grow hungrier, the fear is the bears become more aggressive in 
their search for food and so come closer and closer to town.

The local refuse dump has been closed in the last few weeks to distract 
the bears, but they are still a threat.

Sean checks one of the "polar bear traps" his office has installed near 
the beach. It is a large container - shaped like a dustbin - with a door 
that snaps shut as soon as a bear wanders inside to the seal meat strung 
up in a bag.

Once caught, the bear is tranquilised and then netted to be flown away 
to safety by helicopter.

As yet, nobody really knows whether what we are seeing here on the 
shores of Hudson Bay is a direct affect of the greenhouse gases we are 
pumping into the atmosphere.

No-one can say either whether it is a trend that will continue to 
worsen, or a natural cycle that will eventually be reversed.

What is clear is that every year, as the sea-ice goes through its cycle 
of freeze and melt, the polar bears of Churchill will be among the first 
to let us know.

Story from BBC NEWS:
http://news.bbc.co.uk/go/pr/fr/-/1/hi/sci/tech/4447790.stm
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