* Faster thaw than expected in scientific models
* Weather impact expected in U.S. and elsewhere
* Environmentalists, advocates call for policy change
By Deborah Zabarenko
WASHINGTON, Sept 19 Arctic sea ice, a key
indicator of climate change, melted to its lowest level on
record this year before beginning its autumnal freeze,
researchers at the U.S. National Snow and Ice Data Center said
The extent of ice probably hit its low point on Sept. 16,
when it covered 1.32 million square miles (3.42 million square
km) of the Arctic Ocean, the smallest amount since satellite
records began 33 years ago.
Changing weather conditions could further shrink the extent,
the center said. A final analysis is expected next month.
The record was broken on Aug. 26, when the ice shrank below
the record set in 2007. After that, it kept melting for three
more weeks, bringing the ice extent - defined by NSIDC as the
area covered by at least 15 percent ice - to nearly half of the
"We are now in uncharted territory," Mark Serreze, the
center's director, said in a statement. "While we've long known
that as the planet warms up, changes would be seen first and be
most pronounced in the Arctic, few of us were prepared for how
rapidly the changes would actually occur."
The summer ice isn't just dwindling. It is also thin,
relatively fragile seasonal ice instead of the hardier
multi-year ice that can better withstand bright sunlight.
"The strong late-season decline is indicative of how thin
the ice cover is," said NSIDC's Walt Meier. "Ice has to be quite
thin to continue melting away as the sun goes down and fall
The Arctic is a potent weather-maker for the temperate zone,
and is sometimes dubbed Earth's air conditioner for its cooling
effects. However, as ice wanes and temperatures rise in the far
north, the Arctic could add more heat and moisture to the
MORE EXTREME WEATHER?
"What happens in the Arctic doesn't stay in the Arctic,"
said Dan Lashof, a climate scientist at the nonprofit Natural
Resources Defense Council. "This has a real impact on Americans
where they live and work."
Melting Arctic ice changes the shape and position of the
jetstream, allowing tropical air to penetrate further north and
Arctic air to penetrate further south, Lashof said in a
telephone interview, leading to more extreme weather.
"That is a truly staggering rate of melting, far beyond what
scientists thought would happen a few years ago," Bob Ward of
the London School of Economics and Political Science said in a
statement. "Policy-makers need to wake up to the scale and pace
of the impacts from climate change."
Recent climate models suggest the Arctic could be free of
ice before 2050. But the observed rate of melting is faster than
what is shown in many of the models, according to NSIDC
scientist Julienne Stroeve.
Both the Northwest Passage along Canada's coast and the
Northern Sea Route along Russia were open to traffic this
summer, and investors gathered in Alaska last month to discuss
commercial and transportation opportunities for the Arctic.
The environmental group Greenpeace International took issue
with that approach.
"Rather than dealing with the root causes of climate change,
the current response from our leaders is to watch the ice melt
and then divide up the spoils," the group's executive director,
Kumi Naidoo said in a statement.