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07-29-2005, 07:42 PM
Satellite data for the month of June show Arctic sea ice has shrunk to a record low, raising concerns about climate change, coastal erosion, and changes to wildlife patterns.
The National Snow and Ice Data Centre in the United States uses remote sensing imagery to survey ice cover at both poles.
The centre says 2002 was a record low year for sea ice cover in the Arctic, since satellite observations began in 1979.
There's evidence that may have been the lowest coverage in a century.
Now scientists fear this year could be worse. June readings indicate the ice is at its lowest limit ever for that time of year.
"It actually melted back farther than normal pretty much everywhere around the Arctic," says Walt Meier of the National Snow and Ice Data Centre in the U.S.
"Where it's been retreating the most has been north of Alaska and north of eastern Siberia."
Meier says the amount of ice that covered the Arctic Ocean in the month of June this year shrunk by a record six per cent below the average rate for the month.
Meier says circulation patterns are bringing more storms and warmer air from the South into the region, and that's helping to break up the ice.
"June is really the first big month of melt in the central Arctic Ocean and so it's an indication that the melt is progressing faster than normal," he says. "And when you start melting the ice you're leaving the open ocean there which absorbs much more solar energy and so it tends to heat up even more."
Less sea ice means more moisture in the air and more rain.
It also leads to an increase in coastal erosion since the ice isn't there to buffer the shoreline from waves.
Meier says the ice has retreated almost everywhere in the Arctic except for a small area in the East Greenland Sea.
Dr. Andrew Derocher, a polar bear biologist at the University of Alberta in Edmonton, says less sea ice could have other impacts on northerners.
It could shorten the feeding time for polar bears and bring more of them into the communities.
"It may mean that they're going to have to be particularly careful and on the lookout for more bears than they might normally find in some of the areas where they're camping during the summer until the ice comes back," he says.
The National Snow and Ice Data Centre says Arctic sea ice usually recovers in the winter time.
But researchers have noticed ice has begun to decline in that season as well.
Now some scientists are wondering if the melting of the sea ice has already gone beyond a critical threshold from which it can't recover.
The National Snow and Ice Data Centre in the United States uses remote sensing imagery to survey ice cover at both poles.
The centre says 2002 was a record low year for sea ice cover in the Arctic, since satellite observations began in 1979.
There's evidence that may have been the lowest coverage in a century.
Now scientists fear this year could be worse. June readings indicate the ice is at its lowest limit ever for that time of year.
"It actually melted back farther than normal pretty much everywhere around the Arctic," says Walt Meier of the National Snow and Ice Data Centre in the U.S.
"Where it's been retreating the most has been north of Alaska and north of eastern Siberia."
Meier says the amount of ice that covered the Arctic Ocean in the month of June this year shrunk by a record six per cent below the average rate for the month.
Meier says circulation patterns are bringing more storms and warmer air from the South into the region, and that's helping to break up the ice.
"June is really the first big month of melt in the central Arctic Ocean and so it's an indication that the melt is progressing faster than normal," he says. "And when you start melting the ice you're leaving the open ocean there which absorbs much more solar energy and so it tends to heat up even more."
Less sea ice means more moisture in the air and more rain.
It also leads to an increase in coastal erosion since the ice isn't there to buffer the shoreline from waves.
Meier says the ice has retreated almost everywhere in the Arctic except for a small area in the East Greenland Sea.
Dr. Andrew Derocher, a polar bear biologist at the University of Alberta in Edmonton, says less sea ice could have other impacts on northerners.
It could shorten the feeding time for polar bears and bring more of them into the communities.
"It may mean that they're going to have to be particularly careful and on the lookout for more bears than they might normally find in some of the areas where they're camping during the summer until the ice comes back," he says.
The National Snow and Ice Data Centre says Arctic sea ice usually recovers in the winter time.
But researchers have noticed ice has begun to decline in that season as well.
Now some scientists are wondering if the melting of the sea ice has already gone beyond a critical threshold from which it can't recover.