August 19, 2000
Ages-Old Polar Icecap Is Melting, Scientists Find
By JOHN NOBLE WILFORD
The North Pole is melting. The thick ice that has for ages
covered the Arctic Ocean at the pole has turned to water, recent
visitors there reported yesterday. At least for the time being,
an ice-free patch of ocean about a mile wide has opened at the
very top of the world, something that has presumably never
before been seen by humans and is more evidence that global
warming may be real and already affecting climate.
The last time scientists can be certain the pole was awash in
water was more than 50 million years ago.
"It was totally unexpected," said Dr. James J. McCarthy, an
oceanographer, director of the Museum of Comparative Zoology at
Harvard University and the co-leader of a group working for the
Intergovernmental Panel on Climate Change, which is sponsored by
the United Nations. The panel is studying the potential
environmental and economic consequences of marked climate
change.
Dr. McCarthy was a lecturer on a tourist cruise in the Arctic
aboard a Russian icebreaker earlier this month. On a similar
cruise six years ago, he recalled, the icebreaker plowed through
an icecap six to nine feet thick at the North Pole.
This time, ice was generally so thin that sunlight could
penetrate and support concentrations of plankton growing under
the ice. Dr. McCarthy said the icebreaker's Russian captain, who
has made the voyage 10 times in recent years, said he had never
before encountered open water at the pole.
Another lecturer, Dr. Malcolm C. McKenna, a paleontologist at
the American Museum of Natural History, said the ship, the
Yamal, crunched through miles of unusually thin ice and
intermittent open water on the approach from Spitsbergen,
Norway, to the pole. When the ship reached the pole -- which Dr.
McKenna and his wife, Priscilla, confirmed with a hand-held
Global Positioning System Priscilla, confirmed with a hand-held
Global Positioning System navigation device -- water lapped its
bow.
"I don't know if anybody in history ever got to 90 degrees north
to be greeted by water, not ice," Dr. McKenna said in an
interview. He instantly snapped pictures to document the
phenomenon in photographs.
The Yamal eventually had to steam six miles away to find ice
thick enough for the 100 passengers to get out and be able to
say they had stood on the North Pole, or close to it. They saw
ivory gulls flying overhead, the first time ornithologists said
they had ever been sighted at the pole.
Over the last century, the average surface temperature of the
globe has risen by about 1 degree Fahrenheit, and the rate of
warming has accelerated in the last quarter century. (That's a
significant amount, considering that the world is only 5 to 9
degrees warmer now than it was in the last ice age, 18,000 to
20,000 years ago.) Scientists and policy makers are still
arguing about whether this is a natural fluctuation or an effect
of industrial society's releasing heat-trapping gasses into the
atmosphere.
"Some folks who pooh-pooh global warming might wake up if shown
that even the pole is beginning to melt at least sometimes, as
in the Eocene," Dr. McKenna added.
The Eocene was the geological period when the world's climate
grew significantly warmer. Around 55 million years ago,
according to sedimentary and fossil evidence, tropical
vegetation spread inside the Arctic and Antarctic circles. Water
and jungles dominated the polar environments, and in the
generally warm world, mammals for the first time grew in number,
size and diversity.
Previous studies of satellite and submarine observations have
seemed to establish a warming trend in the northern polar region
and raise the possibility of a melting icecap.
Scientists at the Goddard Space Science Institute, a NASA
research center in Manhattan, compared data from submarines in
the 1950's and 60's with 90's observations, demonstrating that
the ice cover over the entire Arctic basin has thinned by 45
percent. Satellite images have revealed that the extent of ice
coverage has significantly shrunk in recent years.
Dr. McCarthy said he would report the encounter with open polar
water to environmental scientists and consult other scientists
to see if new satellite remote-sensing data have detected the
extent of the melting.
Recalling the reaction of passengers when they saw an iceless
North Pole, he said: "There was a sense of alarm. Global warming
was real, and we were seeing its effects for the first time that
far north."
In their models of climate patterns, scientists have long
suggested that the northern polar region would be affected
earlier and more seriously than the southern region.
They said the greater expanse of land in the northern hemisphere
should respond more rapidly to temperature change, presumably
leading to marked climate change.
SOURCE: The New York Times
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