- The sea ice surrounding the North Pole is vanishing more
quickly than scientists had suspected, threatening the only natural habitat
of the polar bear.
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- New satellite measurements collected by a team of British
researchers have shown that the longer Arctic summers of the past few decades
have thinned the ice dramatically.
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- The findings suggest an uncertain future for polar bears,
the biggest land predators in the world.
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- The creatures are dependent on sea ice to catch seals
and although not yet classified as endangered, they are suffering the effects
of climate change in areas such as Hudson Bay, Canada.
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- The findings could also have implications for the speed
of climate change in the Arctic and in Britain. Northern sea ice is thought
to play an important role in the operation of the Gulf Stream - the flow
of warm water from the mid-Atlantic that keeps northern Europe warm.
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- The ice covering the Arctic Ocean is only nine feet thick.
Data from submarines has shown that it has thinned by around 40 per cent
since the 1960s. Past studies based on computer models suggested that the
decrease in ice cover was caused by changing wind patterns.
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- But the new research, based on satellite observations,
confirms that longer Arctic summers are to blame.
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- Dr Seymour Laxon, from the Centre for Polar Observation
and Modelling at University College London, who led the study, published
in Nature, said the Arctic summers were getting five days longer every
decade. "When we compared the data from the satellites, we were astonished
by the similarity between changes in ice thickness and the length of the
summer melt seasons," he said.
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- "This result suggests that if this continues, further
melting will occur, leading to the eventual disappearance of the ice during
the summer.
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- The team, which also included scientists from the Met
Office Hadley Centre for Climate Prediction, used satellite radar to measure
the top one tenth of the ice layer and estimate the thickness.
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- "The melting won't cause sea levels to rise, but
removing ice will allow more sunlight to be absorbed, further raising temperatures,"
said Dr Laxon. "Models predict a temperature increase of three times
the global average in the Arctic because of this."
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- Polar bears live in the Arctic regions of Canada, Alaska,
Russia, Greenland and Norway. There are thought to be fewer than 27,000
in the wild, with 15,000 living in Canada.
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- © Copyright of Telegraph Group Limited 2003.
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- http://www.telegraph.co.uk/news/main.jhtml?xml=/news
- /2003/10/30/wpole30.xml&sSheet=/news/2003/10/30/ixworld.html
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