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Nature and man jointly cook Arctic
By SETH BORENSTEIN, AP Science Writer
Wed Jan 2, 9:38 PM ET
http://news.yahoo.com/s/ap/20080103/ap_on_sc/arctic_warming
WASHINGTON - There's more to the recent dramatic and alarming thawing
of the Arctic region than can be explained by man-made global warming
alone, a new study found. Nature is pushing the Arctic to the edge,
too.
There's a natural cause that may account for much of the Arctic
warming, which has melted sea ice, ice sheets and glaciers, according
to a study published Thursday in the journal Nature. New research
points a finger at a natural and cyclical increase in the amount of
energy in the atmosphere that moves from south to north around the
Arctic Circle.
But that energy transfer, which comes with storms that head north
because of ocean currents, is not acting alone either, scientists say.
Another upcoming study concludes that the combination of both that
natural energy transfer increase and man-made global warming serve as
a one-two punch that is pushing the Arctic over the edge.
Scientists are trying to figure out why the Arctic is warming and
melting faster than computer models predict.
The summer of 2007, like the summer of 2005, smashed all records for
loss of summer sea ice in the Arctic Ocean and ice sheet in Greenland.
In September, the Arctic Ocean had 23 percent less sea ice than the
previous record low. Greenland's ice sheet melted 19 billion tons more
than its previous record.
The Nature study suggests there's more behind it than global warming
because the air a couple miles above the ground is warming more than
calculated by the climate models.
Climate change theory concentrates on warming of surface temperatures
and explains an Arctic that is warming faster than the rest of the
world as mostly because reduced sea ice and ice sheets means less
reflecting solar rays.
Rune Graversen, the Nature study co-author and a meteorology
researcher at Stockholm University in Sweden, said a shift in energy
transfer explains the thawing more, including what's happening in the
atmosphere, but does not contradict consensus global warming science.
Oceanographer James Overland, who reviewed Graversen's study for
Nature, said the research dovetails with an upcoming article of his
which concludes that the Arctic thawing is a combination of the two.
"If we didn't have the little extra kick from global warming then we
wouldn't have gone past the threshold for the change in sea ice," said
Overland, of the National Oceanic and Atmospheric Administration's lab
in Seattle.
Other researchers said Graversen's study underestimates the effect of
global warming because it relied on older data that stopped at 2001
and wasn't the most accurate.
Overland and scientist Mark Serreze disagree over which effect
Nature and man jointly cook Arctic
By SETH BORENSTEIN, AP Science Writer
Wed Jan 2, 9:38 PM ET
http://news.yahoo.com/s/ap/20080103/ap_on_sc/arctic_warming
WASHINGTON - There's more to the recent dramatic and alarming thawing
of the Arctic region than can be explained by man-made global warming
alone, a new study found. Nature is pushing the Arctic to the edge,
too.
There's a natural cause that may account for much of the Arctic
warming, which has melted sea ice, ice sheets and glaciers, according
to a study published Thursday in the journal Nature. New research
points a finger at a natural and cyclical increase in the amount of
energy in the atmosphere that moves from south to north around the
Arctic Circle.
But that energy transfer, which comes with storms that head north
because of ocean currents, is not acting alone either, scientists say.
Another upcoming study concludes that the combination of both that
natural energy transfer increase and man-made global warming serve as
a one-two punch that is pushing the Arctic over the edge.
Scientists are trying to figure out why the Arctic is warming and
melting faster than computer models predict.
The summer of 2007, like the summer of 2005, smashed all records for
loss of summer sea ice in the Arctic Ocean and ice sheet in Greenland.
In September, the Arctic Ocean had 23 percent less sea ice than the
previous record low. Greenland's ice sheet melted 19 billion tons more
than its previous record.
The Nature study suggests there's more behind it than global warming
because the air a couple miles above the ground is warming more than
calculated by the climate models.
Climate change theory concentrates on warming of surface temperatures
and explains an Arctic that is warming faster than the rest of the
world as mostly because reduced sea ice and ice sheets means less
reflecting solar rays.
Rune Graversen, the Nature study co-author and a meteorology
researcher at Stockholm University in Sweden, said a shift in energy
transfer explains the thawing more, including what's happening in the
atmosphere, but does not contradict consensus global warming science.
Oceanographer James Overland, who reviewed Graversen's study for
Nature, said the research dovetails with an upcoming article of his
which concludes that the Arctic thawing is a combination of the two.
"If we didn't have the little extra kick from global warming then we
wouldn't have gone past the threshold for the change in sea ice," said
Overland, of the National Oceanic and Atmospheric Administration's lab
in Seattle.
Other researchers said Graversen's study underestimates the effect of
global warming because it relied on older data that stopped at 2001
and wasn't the most accurate.
Overland and scientist Mark Serreze disagree over which effect
