Polar bear report - Sean

POLAR BEAR REPORT

by Sean Beavis

Polar bears by Sean Beavis

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Polar Bears

Polar bears live on pack ice in the Arctic.

The ice provides them with a place to hunt, live & breed. Pack Ice forms when sea water freezes, there is more pack ice during winter. Sea ice is an ecosystem of plankton & micro-organisms, which seals feed on , & the polar bears then feed on the seals.


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As the Arctic warms, the sea ice declines & the Polar bears must follow the ice flow for their food.

(Solid red line indicates yearly average minimum pack-ice - dotted line indicates yearly average maximum)

Unfortunately there is now more ice melting each summer & it is becoming a problem for the polar bears. In the Hudson Bay in Canada the bears are fac-ing a grave threat to their sur-vival, as the ice there is decreas-ing more each year.

The world Conservation Union has listed Polar bears as a threatened species.

Here is a list of some things that are affecting Polar bears :

men have hunted them

Pollution in their habitat

Men looking for oil in the Arctic.

FOOD/HABITAT

The thinness of the ice covering the Arctic Ocean, approximately three metres deep, which makes it far more vulnerable to longer summers than the glaciers

of the Antarctic. Since the 1960s a 40% thinning of the ice has occurred. Polar bears rely on the ice to hunt for seals, and because it is breaking-up earlier it is giving them less time to hunt. The more the Arctic melts the more it affects global warming because it decreases the amount of sunlight reflected by the ice. The Arctic ice plays an important role in the operation of the Gulf Stream, and because more ice is melting it increases the chance of disrupting it.

Previously scientists thought that the decrease in ice cover was caused by changing wind pat-terns, they used computer models to work this out. The information we have now is based on observation and measurements made possible by the use, of radar data from a European Space


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Agency satellite and microwave images obtained from an American satellite. They use all this data to determine any possible changes in the length of the Arctic summer.

Dr Seymour Laxon, from the Centre for Polar Observation and Modelling at UCL, said: "Re-sults from the American satellite have shown that the length of summers has increased over the last 25 years. When we compared the data from the two satellites we were astonished by the similarity between changes in the ice thickness and the length of the summer melt season. This result suggests that if this continues, further melting will occur, leading to the eventual disappearance of the ice during summer."

The amount of Arctic sea ice created during January 2011 was the lowest in the satellite record for that month. In the winter of 2011 the maximum amount of Arctic sea ice was the same as the lowest on record, and since observation began in 1979, these have been the second lowest Arctic ice levels recorded.

POPULATION

Population sizes are decreasing because of the reduced amount of hunting time because the pack ice melts earlier and earlier each year. As the sea ice platforms move farther apart they make swimming conditions more dangerous, and its more likely that they won’t make it back, and their cubs are less likely to survive. The further they have to swim the more body fat they loose. In 2004 biologists found 4 drowned Polar Bears in the Beaufort Sea, they think that many more may have actually drowned. It is possible that


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the distance between land fall and pack ice is making the seas rougher and harder for the Polar Bears to swim through.

“A female polar bear reportedly swam for nine days - nonstop-across the Beaufort Sea before reaching an ice floe, costing her 22 percent of her weight and her cub” (National Wildlife Federation)

The U.S. Geological Survey has projected that 2/3 of polar bears will disappear by 2050. This is but a minuscule fraction of the time polar bears have roamed the vast Arctic seas, and is occur-ring during our lifetime. We have a responsibility to be more eco friendly to slow the global warming process.

Rapid Arctic ice melt in 2011:

HISTORY

In the southern most areas of Polar Bear habitat - the Hudson Bay in Canada - there is now no sea ice during summer, which means that the Polar Bears have to live on the land and they end up eating little or nothing. They then have to wait until the the Hudson Bay freezes in Autumn so that they can go hunting on the ice again.

During the last 20 years the Hudson Bay amount of ice-free periods has increased by an average of 20 days. This cuts the Polar Bears hunting season by nearly 3 weeks. Because the ice freezes later and later and melts earlier, the Polar Bears have less hunting time. This also means that


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their average weight has dropped by about 15%, this then has an effect on their ability to re-produce. The Hudson Bay Polar Bear population has reduced by around 20%.

CONCLUSION

The reduction in sea ice combined with late freezing and earlier melting means that not only is the habitat in which they live declining, but the amount of hunting time they have is also de-clining. This results in weight loss, fewer breeding couples, less cubs born and more cubs dying from starvation and drowning. As their habitat slowly shrinks, the Grizzly Bears habitat is growing and they are beginning to invade the Polar Bears habitat, this could also pose a major threat to the Polar Bear - a new predator. Humans are also invading their habitat in the form of petroleum industries - there are already large oil and gas operations in the Arctic and it looks as though this will be expanding in the coming years to offshore as well. The risk of oil spills could be a huge danger to Polar Bears, Seals, and plankton - the circle of life. The Polar Bear can be seen as the "canary in the coal mine" when we are studying global warming and its link to wildlife species around the world. We need to look after the world and environment, as we are all linked in one way or another and if we start loosing these awesome animals - then slowly the food chain shrinks and so does our food source.

BIBLIOGRAPHY

BBC Home page

National Wildlife Federation/Global-Warming/Effects on Wildlife

kidzone

polarbears international.org

wikipedia

Eyewitness Living Earth, Dorling Kindersley, Pub 1996 in Great Britian

Polar Bears (Animals in Danger), TickTock Books


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Education

Polar bear report - Sean