By Emily Stifler Explorebigsky.com Managing Editor
SEATTLE—Greenland’s contribution
to rising sea level in the 21st century
might be significantly less than some
scientists thought possible, according
to new research. The study,
published by Big Sky resident Twila
Moon, focuses on changes in the
speed ice travels in more than 200 of
Greenland’s outlet glaciers.
“So far, on average we’re seeing about
a 30 percent speedup in 10 years,”
said Moon, who is working toward a
Ph.D. in Earth and Space Sciences at
the University of Washington.
Moon was lead author of a paper documenting
the observations published
May 4 in Science, one of the most
influential magazines in physical and
biological sciences.
Although she’s done fieldwork on the
Greenland ice sheet in the past, this
research is based on satellite data. For
Moon, that means it’s all computer
based and she can work from her Big
Sky home half the year.
“The whole paper got written sitting
in my home office, looking at whatever
weather was coming over from
the west,” she said.
Moon thought of the project when
she started graduate school in 2010,
and was drawn to it because of an
interest in climate science and how
climate change will impact the planet,
she said.
The Greenland and Antarctic ice
sheets hold “unimaginable amounts of
ice,” Moon said, describing them as a
“Mars on Earth sort of place,” in that
there are still basic unanswered questions
about them.
At this point, she said, ice sheets
remain one of the biggest questions in
predicting future sea level rise.
Moon and her peers know that the
faster the glaciers move, the more ice
and meltwater they release into the
ocean, and “the potential sea level rise
from losing ice from those ice sheets
is going to have impact all over the
world.”
In the study, Moon and her co-authors
created a decade-long record of
changes in Greenland outlet glaciers
by producing velocity maps with data
from Canadian, German and Japanese
satellites. They started during the
2000-01 winter and repeated the
process for each winter from 2005-
06 through 2010-11, and found the
outlet glaciers hadn’t increased in
velocity as much as previous studies
speculated.
The record showed a complex pattern.
Nearly all of Greenland’s largest
glaciers that meet land move at top
speeds of 30 to 325 feet a year, and
their changes in speed are small because
they’re already moving slowly.
Glaciers that terminate in fjord ice
shelves move at 1,000 feet to a mile
a year, but didn’t gain notable speed
during the decade.
In the east, southeast and north –
west areas of Greenland, glaciers
that end in the ocean can travel
seven miles or more in a year. Their
changes in speed varied during the
decade, and some even slowed. In
the northwest they increased by 28
percent on average, and 32 percent
in the southeast.
But the scientists saw no clear indication
that the glaciers would stop
gaining speed during the rest of the
century.
“It’s a pretty hot topic field, and there’s a
lot happening in it all the time,” Moon
said. “It’s fun to be working on the very
frontier of this sort of science.”
