[NYTr] Env: At the Poles, Melting Occurring at Alarming Rate

[All the News That Doesn't Fit]

The Washington Post - Oct 22, 2007
http://www.washingtonpost.com/wp-dyn/content/article/2007/10/21/AR2007102100761_pf.html

At the Poles, Melting Occurring at Alarming Rate

By Doug Struck
Washington Post Staff Writer

For scientists, global warming is a disaster movie, its opening scenes
set at the poles of Earth. The epic already has started. And it's not
fiction.

The scenes are playing, at the start, in slow motion: The relentless
grip of the Arctic Ocean that defied man for centuries is melting away.
The sea ice reaches only half as far as it did 50 years ago. In the
summer of 2006, it shrank to a record low; this summer the ice pulled
back even more, by an area nearly the size of Alaska. Where explorer
Robert Peary just 102 years ago saw "a great white disk stretching away
apparently infinitely" from Ellesmere Island, there is often nothing
now but open water. Glaciers race into the sea from the island of
Greenland, beginning an inevitable rise in the oceans.

Animals are on the move. Polar bears, kings of the Arctic, now search
for ice on which to hunt and bear young. Seals, walrus and fish adapted
to the cold are retreating north. New species -- salmon, crabs, even
crows -- are coming from the south. The Inuit, who have lived on the
frozen land for millennia, are seeing their houses sink into
once-frozen mud, and their hunting trails on the ice are pocked with
sinkholes.

"It affects everyone," said Carin Ashjian, a Woods Hole Oceanographic
Institute scientist who spent early September with native Inupiats in
Barrow, the northernmost town of Alaska. "The only ice I saw this year
was in my cup at the cafeteria."

At the South Pole, ancient ice shelves have abruptly crumbled. The air
over the western Antarctic peninsula has warmed by nearly 6 degrees
since 1950. The sea there is heating as well, further melting edges of
the ice cap. Green grass and beech trees are taking root on the ice
fringes.

Antarctica's signature Adelie penguins are moving inland, seeking the
cold of their ancestors, replaced by chinstrap and Gentoo penguins,
which prefer open water. Krill, the massive smorgasbord for a food
chain reaching to the whales, are disappearing from traditional
spawning grounds.

"We've seen quite big changes in the living environment," John King, a
lead researcher for the British Antarctic Survey, said from Cambridge,
England.

The scenario is not new. What is most alarming to the scientists is the
speed at which it is unfolding. A decade ago, melting at the poles was
predicted to play out over 100 years. Instead, it is happening on a
scale scientists describe as overnight.

When the Larsen B, an Antarctic ice shelf the size of Rhode Island,
collapsed in 2002, "it was a big glaring clue that something not
natural was happening," said Hugh Ducklow, director of ecosystems for
MBL Laboratories in Woods Hole, Mass. "The geological evidence
suggested that was stable for at least 10,000 years, back to the last
ice age. And it literally disintegrated in three weeks."

The scientists say the coming scenes in the movie, as described by the
historic melding of research assembled by the Intergovernmental Panel
on Climate Change, will be even more disturbing:

As the air warms over Canada, Alaska and Siberia, the melting
permafrost releases millions of tons of trapped carbon and methane,
further accelerating the encroaching disaster. Greenland's moving
glaciers pick up speed, likely bringing in this century the first three
feet of a possible 23-foot rise of the seas that would ultimately
inundate New York City and South Florida and drive millions of people
from low-lying areas of Asia.

The ice shelves collapsing in western Antarctica bring glacier melting
there, pouring as much water into the sea as Greenland. Eventually, the
giant frozen continent of eastern Antarctica, so far insulated from the
rest of the warming planet, may begin to melt. The thermohaline ocean
circulation pattern begins to slow.

"I just don't see a happy ending for this," said Ted Scanbos, who
studies the polar ice at the National Snow and Ice Data Center at the
University of Colorado.

Most scientists say the changes anticipated at the poles in the next 30
to 40 years are inevitable, and averting more severe effects will take
a drastic reduction in emissions of greenhouse gases. Some have
advanced controversial ideas to exploit the polar systems. At least
three companies have plans to "fertilize" the Southern Ocean with iron
try to soak more carbon dioxide out of the air.

"We are just leveraging a natural process," said Dan Whaley, founder of
Climos, a San Francisco company. Other scientists gathered recently at
the Woods Hole Oceanographic Institute were skeptical of the idea.
"There will be scientific consequences we cannot predict," warned John
Cullen, an oceanographer at Dalhousie University in Halifax.

The polar regions have been regularly described as the canaries in the
coal mine of global warming: remote bellwethers that could give mankind
a heads-up when important changes are coming.

Some even see positive opportunities in the warming. The legendary
Northwest Passage, a sea route from the Atlantic to the Pacific above
North America, is now mostly ice-free in the summer. That opens up
tempting commercial possibilities for shippers and for drillers seeking
vast oil and gas fields under the Arctic Ocean. Arctic nations
including Canada, Norway, the United States and Russia are engaged in
an increasingly urgent race to map out the ocean floor and stake claims
on undersea resources.

But it turns out that the polar regions are far more than simple
alarms. What happens at the poles will -- and is -- affecting the rest
of the world.

Consider the permafrost. The vast Arctic region in the north
encompasses land on three continents that has been deeply frozen since
the last ice age. A thin layer thaws each summer. By mid-century, half
of it will thaw to 10 feet, according to computer models of the
National Center for Atmospheric Research in Boulder, and long-trapped
greenhouse gases will be released.

Already, the melting in Siberia is releasing methane, a potent
greenhouse gas, that had been buried for 40,000 years, feeding a cycle
of more warming and more melting.

"That's a serious runaway," Scanbos said. "A catastrophe lays buried
under the permafrost."

Or consider the ocean currents. The weather in the Northern Hemisphere
is controlled by the temperature of currents that circulate on a giant
treadmill, in which water cooled at the icy poles sinks to the bottom,
and moves slowly toward the equator, where it heats and rises to flow
northward again, mixing the seas. That is why Europe's climate is
relatively moderate.

As the Arctic ice melts and ice shelves collapse in the Southern Ocean,
vast areas of open water are exposed. The water absorbs heat from the
sun that until now was reflected by the ice. As that heat warms the
seas, the treadmill is expected to slow, the IPCC has reported. In the
worst case, it could stop. The previous time that happened, 15,000
years ago, the Northern Hemisphere was plunged into a brief and brutal
ice age, apparently within decades.

"It's like having a pool of warm water sitting in the middle of what is
supposed to be the air conditioner of the north," Scanbos said. "And it
will be within our lives, not our grandchildren's."

The northern Arctic is changing first, and most noticeably. But the
changes there are likely to be followed by a "one-plus-two-plus-three
punch" in the southern polar region, said Ellen Mosley-Thompson, at the
Byrd Polar Research Center at Ohio State University. She has been
drilling and measuring ice in polar regions and mountain glaciers for
25 years, and has lived in frigid tents and battled brutal weather for
weeks at a time to get ice core samples.

The Antarctic has sent complicated signals, she said. The interior is
"a monstrously large ice sheet that creates its own microclimate."
Winds circling Antarctica have buffered it, so average temperatures on
the continent have changed little in 50 years and the snowpack in the
interior has been growing.

Furthermore, Antarctica's ice sits on land, and the warming of even the
most gloomy predictions is unlikely to make a big dent in that huge ice
pack very soon.

But western Antarctica and the peninsula that juts northward have a
different weather scheme. The air over the Antarctic peninsula is one
of three places on the globe with the fastest heating; Arctic western
Canada and Alaska and the high mountains of China and Tibet are the
others. The sea water also is heating, accelerating the breakup of ice
shelves that stick out over the sea. When they go, the glaciers on land
behind them begin to accelerate their slide to the sea, adding to
global sea levels.

"We thought the Southern Hemisphere climate is inherently more stable,"
Scanbos said. But "all of the time scales seem to be shortened now.
These things can happen fairly quickly. A decade or two decades of
warming is all you need to really change the mass balance.

"Things are on more of a hair trigger than we thought."

© 2007 The Washington Post