We're a decade ahead of the worst-case scenario
Scientists scattered througout the Arctic, and those monitoring satellite data as part of the International Polar Year programs, couldn't have timed their research any better.
"The summer of 2007 was stunning", said Doug Bancroft, director of Environmental Canada's Canadian Ice Service.
The Northern Hemisphere is normally covered with 7.5 to 8.5 mln square km's of ice on average, based on 5 decades of record keeping. The amount of ice coverage shrank to a low of 5.3 mln square km's in the summer of 2005.
But on Sept. 17, 2007, scientist calculated that the amount of sea ice hit a new record low of just 4.2 mln square km's.
A NASA-led study released this week, which also recorded the staggering decline in the amount of perennial sea ice, found the bulk of the thickest ice is now confined to the Arctic Ocean north of Canda. But even that isn't immune to the thaw.
The fabled Northwest Passage is normally still choked with ice during the summer. At its usual low point, 14 per cent of the shipping route remains covered with ice, which prevents ships from passing unless escorted bt icebreakers.
This year, just 2 per cent was covered with ice, resulting in the second consecutive summer during which an unaided sailboat could pass through.
"Along the 2,300 km's of the Northwest Passage you're going around ice for about 20 kms as opposed to the usual 400," Mr. Bancroft said.
A consensus has grown in the scientific community that global warming caused by human activity is contributing to the changing face of the Arctic. But experts say it was the peculiar weather Mother Nature offered up last summer - whatever caused it - that is largely to blame for the recent unusual events. There was a high-pressure system that sat over the Arctic for much of the summer. It shooed away clouds, leaving the sun alone to beat down.
Son Nghiem, who led that NASA study on sea ice released this week, also pointed to unusual winds, which compressed sa ice, pushing it into the Transpolar Drift Stream and into warmer water where melting happened more quickly.
Scott Lamoureux, a geography professor at Queen's University in Kingston, noticed the summer's odd weather firsthand on Melville Island north of the Arctic Circle where he's studying how climate change is affecting river flow, soil moisture, vegetation and water quality. Tat far north, the mean temperature has been reported at just under 4C in July since records were first kept in the 1950s.
"What we observed through much July were temperatures in the 15-to-20 C range. The highest temperateure recorded was almost 22, Prof. Lamoureux said.
He also noted other weird things he hedn't noticed in the 5 years working there.
Whkile the summer melt usually sinks 50 cm's into the permafrost, the melt depth was down at least a metre or more this year. That caused land to fracture, as well as large slides and flooding. One piece of alnd slid down a hill and dammed a river 200 metres across, he said.
"It's not surprising that this kind of things could happen, but it's the scale and how rapidly it could occur," Prof Lamoureux said. "The impact of this, even if it's the only time it happens for the next decade, could be felt on the system for many, many years."
Only recently has the world begun to notice the potential impact of climate change on northern wildlife, plants and people. This year, the dire warnings piled up.
Until now, climate models were predicting that the Arctic would be free of sea ice in the summertime by 2040, 2050 or at the latest 2100, according to Mr. Bancroft. Now, 2030 is a more realistic date for the biggest melt of all.
"We're a decade ahead of the worst-case scenario," he said. Even with moderate projections for shrinking sea ice, the USGS concluded last month that two-thirds of the world's polar bears - there are an estimated 22,000 - will vanish by 2050, and could disappear entirely from Alaska.
"Sea-ice conditions would have to be substantially better than even the most conservative computer simulations of warming and sea-ice" in order to prevent the projected drop in the number of bears, the report says.
NASA even warned that with so much Arctic melt, the planet may be hitting a tipping point. The thaw may be become a self-sustaining acceleration. As the ice shrinks, so does the amount of reflective snow and ice, which in turn leaves the ocean to draw in more heat from the sun. Warmer waters, of course, metl ice more quickly.
The Potsdam Institute for Climate Impact Research in Germany has pronounced that Arctic sea ice has "already tipped".
Back in Chesterfield Inlet yesterday, the snow was flying and the freeze was setting in. "It still looks normal," Mr. Tautu said. He's not worried about a big melt, figuring the polar bears, other animals and the people will adapt. Snow and ice, he said, will always be there. Still he added, times have changed since his elders could read the weather better than any scientist.
"I was taught about the weather when I was a little boy," he said. "Nowadays we can't predict it any more."
--
Met excuses alvast voor typefouten. Was een lang artikel om over te typen!
Scientists scattered througout the Arctic, and those monitoring satellite data as part of the International Polar Year programs, couldn't have timed their research any better.
"The summer of 2007 was stunning", said Doug Bancroft, director of Environmental Canada's Canadian Ice Service.
The Northern Hemisphere is normally covered with 7.5 to 8.5 mln square km's of ice on average, based on 5 decades of record keeping. The amount of ice coverage shrank to a low of 5.3 mln square km's in the summer of 2005.
But on Sept. 17, 2007, scientist calculated that the amount of sea ice hit a new record low of just 4.2 mln square km's.
A NASA-led study released this week, which also recorded the staggering decline in the amount of perennial sea ice, found the bulk of the thickest ice is now confined to the Arctic Ocean north of Canda. But even that isn't immune to the thaw.
The fabled Northwest Passage is normally still choked with ice during the summer. At its usual low point, 14 per cent of the shipping route remains covered with ice, which prevents ships from passing unless escorted bt icebreakers.
This year, just 2 per cent was covered with ice, resulting in the second consecutive summer during which an unaided sailboat could pass through.
"Along the 2,300 km's of the Northwest Passage you're going around ice for about 20 kms as opposed to the usual 400," Mr. Bancroft said.
A consensus has grown in the scientific community that global warming caused by human activity is contributing to the changing face of the Arctic. But experts say it was the peculiar weather Mother Nature offered up last summer - whatever caused it - that is largely to blame for the recent unusual events. There was a high-pressure system that sat over the Arctic for much of the summer. It shooed away clouds, leaving the sun alone to beat down.
Son Nghiem, who led that NASA study on sea ice released this week, also pointed to unusual winds, which compressed sa ice, pushing it into the Transpolar Drift Stream and into warmer water where melting happened more quickly.
Scott Lamoureux, a geography professor at Queen's University in Kingston, noticed the summer's odd weather firsthand on Melville Island north of the Arctic Circle where he's studying how climate change is affecting river flow, soil moisture, vegetation and water quality. Tat far north, the mean temperature has been reported at just under 4C in July since records were first kept in the 1950s.
"What we observed through much July were temperatures in the 15-to-20 C range. The highest temperateure recorded was almost 22, Prof. Lamoureux said.
He also noted other weird things he hedn't noticed in the 5 years working there.
Whkile the summer melt usually sinks 50 cm's into the permafrost, the melt depth was down at least a metre or more this year. That caused land to fracture, as well as large slides and flooding. One piece of alnd slid down a hill and dammed a river 200 metres across, he said.
"It's not surprising that this kind of things could happen, but it's the scale and how rapidly it could occur," Prof Lamoureux said. "The impact of this, even if it's the only time it happens for the next decade, could be felt on the system for many, many years."
Only recently has the world begun to notice the potential impact of climate change on northern wildlife, plants and people. This year, the dire warnings piled up.
Until now, climate models were predicting that the Arctic would be free of sea ice in the summertime by 2040, 2050 or at the latest 2100, according to Mr. Bancroft. Now, 2030 is a more realistic date for the biggest melt of all.
"We're a decade ahead of the worst-case scenario," he said. Even with moderate projections for shrinking sea ice, the USGS concluded last month that two-thirds of the world's polar bears - there are an estimated 22,000 - will vanish by 2050, and could disappear entirely from Alaska.
"Sea-ice conditions would have to be substantially better than even the most conservative computer simulations of warming and sea-ice" in order to prevent the projected drop in the number of bears, the report says.
NASA even warned that with so much Arctic melt, the planet may be hitting a tipping point. The thaw may be become a self-sustaining acceleration. As the ice shrinks, so does the amount of reflective snow and ice, which in turn leaves the ocean to draw in more heat from the sun. Warmer waters, of course, metl ice more quickly.
The Potsdam Institute for Climate Impact Research in Germany has pronounced that Arctic sea ice has "already tipped".
Back in Chesterfield Inlet yesterday, the snow was flying and the freeze was setting in. "It still looks normal," Mr. Tautu said. He's not worried about a big melt, figuring the polar bears, other animals and the people will adapt. Snow and ice, he said, will always be there. Still he added, times have changed since his elders could read the weather better than any scientist.
"I was taught about the weather when I was a little boy," he said. "Nowadays we can't predict it any more."
--
Met excuses alvast voor typefouten. Was een lang artikel om over te typen!
Bericht laatst bijgewerkt: 04-10-2007 12:03