November
2007
A firsthand look at disappearing sea ice
The U.S. Coast Guard Cutter Healy sails through patches of sea ice on its cruise north
from Barrow. (Photo by Steve Roberts.) |
In August, Steve Roberts (EOL) sailed north from Barrow,
Alaska. The U.S. Coast Guard cutter that carried him, the
Healy, is the country’s newest and most technologically
advanced polar icebreaker. Measuring 420 feet, it served
as a floating home for 26 researchers, about 90 crew members,
and an array of scientific instruments, all bound for 80ºN.
The only thing missing on the cruise was ice. During normal
summers, ships can expect to encounter sea ice about 30 miles
north of Barrow. The Healy sailed 280 miles, to 75ºN,
before it reached ice. “And this was early in the melt
season, so there was still a lot more melting to occur,” Steve
notes.
Later in the cruise, the ship made it to 82ºN, farther
than planned, before it had to return to Barrow to stay on
schedule. “When we started heading south from our northernmost
excursion we were able to come out of the ice edge at 81.5ºN,
which is truly astounding,” Steve says.
“This year was quite a dramatic change,” he continues. “Everyone
on the ship was talking about the ice. It was depressing.”
A polar bear watches the Healy
sail past. (Photo by Steve Roberts.) |
Steve, a software engineer, has been participating on
Arctic cruises since 2002. He’s a member of a small group
of civilian technicians, managed by the Lamont-Doherty Earth
Observatory, who provide technical support for all Healy missions. EOL enables his participation through NSF’s
Office of Polar Programs.
This particular cruise was in support of the NOAA-funded
Law of the Sea mapping program, related to the Law of the
Sea Treaty, an international agreement that defines the rights
and responsibilities of nations using the world’s oceans.
Steve set sail on the Healy in Seattle, stopping in Barrow
before heading north to within 500 miles of the North Pole,
and then returning to Seattle via Juneau and the Inside Passage.
The entire trip lasted two months.
In addition to not encountering sea ice until much farther
north than usual, the researchers also observed distinctly
less pack ice (ice that never completely thaws in the summer)
than would normally be expected. Although their primary
mission was not to study sea ice, they noticed that what
little multiyear ice they encountered was probably less than
four years old, whereas in the 1970s much of the Arctic was
likely covered by 10- to-30-year-old ice.
Satellites provide a daily view of sea ice extent across
the Arctic Ocean, but they generally can’t diagnose
its thickness, which indicates its age. Icebreakers and submarines
can gather this data, but their limited tracks leave much
of the Arctic unsampled.
In September, scientists at the National Snow and Ice Data
Center reported that the Arctic sea ice minimum for 2007
shattered all previous lows since satellite records began
about 30 years ago. On September 16, the sea ice extent measured
1.59 million square miles (4.13 million square kilometers).
This was about 1 million square miles less than the average
mimimum from 1979 to 2000, equivalent to an area about the
size of Alaska and Texas combined.
Steve plans to return to the Arctic
on the Healy next summer. “But I’m wondering
if I’m going to be out of a job soon,” he says. “Who’s
going to need an icebreaker?”
In this issue...
IPCC
contributors share in Nobel Peace Prize
Remembering
John Firor and Janet Roberts
Sunrise
test flight successful
Same
library, new home
A
firsthand look at disappearing sea ice
NCAR
launches Women in Science committee
Fantastic
forum
Staff
win awards for science, multicultural service
Just One Look
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