Scientists Warn of Melting Ice in Arctic
By DAN JOLING, Associated Press Writer
Mon Feb 6, 10:49 PM ET
Scientists on Monday painted a gloomy picture of the effects of
global warming on the Arctic, warning of melting ocean ice, rising
oceans, thawed permafrost and forests susceptible to bugs and
fire.
"A lot of the stories you read make it sound like there's
uncertainty," said Jonathan Overpeck, a professor of geosciences at
the University of Arizona. "There's not uncertainty."
The questions scientists continue to address, he said after his
presentation at the Alaska Forum on the Environment, are how much
of the warming is caused by humans and how drastic long-term
effects will be.
Deborah Williams, a conference organizer and former director of the
Alaska Conservation Foundation, said Alaska is Ground Zero for
observing the effects of global warming because so many natural
phenomena are tied to ice and the repercussions of it
melting.
"We are the Paul Revere of global warming," she said.
Overpeck reviewed NASA studies showing how Arctic ice has shrunk in
size and depth. Climate models 25 years ago predicted a shrinking
ice pack.
"What we didn't predict is that it would be so dramatic," Overpeck
said.
Scientists predict the summertime Arctic could be ice free before
the end of the century, opening up northern sea routes but
threatening the existence of polar bears, a marine mammal that
depends on sea ice to live.
Other scientists ticked off the effects of warming on fish, forests
and tundra.
James Overland, a research scientist with the National Oceanic and
Atmospheric Administration for more than 30 years, said the loss of
sea ice has meant some marine life has thrived and some has been
hurt.
"The marine ecosystem is shifting north dramatically," he
said.
Pollock are thriving in warmer water. Pink salmon are being found
in great numbers farther north, "an incredible indicator of
warming," he said. Crab and other bottom-dwellers who depend on ice
overhead for part of the year are suffering.
Glenn Juday, professor of forest ecology at the University of
Alaska Fairbanks, said tree growth has decreased at Interior Alaska
sites that were promising for commercial harvest. Studies of
temperatures at Talkeetna and Fairbanks indicate daily lows are not
as low as they used to be. The warming lowers the water available
to white spruce, black spruce and birch, Juday said.
"The warmer it is, the less the trees grow," Juday said. Warming
also makes them more susceptible to fire and insects.
Vladimir Romanovsky, an associate professor of geophysics at UAF,
reviewed effects of warming on permafrost, or ground continuously
frozen for two years. Areas of thick permafrost in the far north
remain stable but have warmed over 20 years one-half to 2 degrees
at a depth of 20 meters, Romanovsky said.
Matthew Sturm of Cold Regions Research and Engineering Laboratory
studied shrubs in Arctic tundra by comparing 50-year-old
photographs taken along the Chandalar River for the National
Petroleum Reserve-Alaska with photos taken recently.
"They all pretty much tell the same story," he said.
Shrubs have thrived in the greater warmth and in turn accelerate
warming. Like open water in the ocean, shrubs darken what otherwise
would be a mostly white, reflective snow-covered environment, Sturm
said.
If warming trends continue, Overpeck said, the globe eventually
will get a nasty message from the Arctic: a rise in sea levels.
Higher oceans will flow into low-lying parts of the world such as
New Orleans, making recovery in that hurricane-ravaged city
moot.
"It's hard to imagine why we're wanting to rebuild if we're going
to allow global warming," Overpeck said.