http://www.latimes.com/news/printedition/asection/la-sci-glacier18oct18,1,3152955.story?coll=la-news-a_section
October 18, 2003
SCIENCE FILE
Patagonian
Glaciers Thinning at Torrid Pace
By Usha Lee McFarling, Times Staff Writer
A new study shows the
great glaciers of the Patagonian ice fields
between Chile and Argentina have retreated twice as fast in recent
years as they did a quarter-century ago.
The area, home to the
largest collection of Southern Hemisphere
ice outside of Antarctica, has been little studied because of
its forbidding location in the Andes between rough Chilean fiords
and harsh deserts. Heavy cloud and snow cover has made the area
difficult to survey with satellites and planes.
A team led by Eric
Rignot of NASA's Jet Propulsion Laboratory
compared sparse data collected on past expeditions to the ice
with precision topographical information obtained during a
2000 space shuttle mapping mission. The team found the glaciers
were retreating and thinning much faster than expected and
at a rate that could not be explained solely by the rising
temperatures and decreased precipitation seen in the last
half-century.
Rignot and his Chilean
colleagues theorize that "ice dynamics"
are playing a role in the rapid retreat, and that calving glaciers
that break off over water, as opposed to land, retreat even faster
once the water beneath them deepens.
The new work, published
in the current issue of Science, could
help predict the future behavior of glaciers in other parts of
the world, including Greenland and Antarctica. The loss of ice
in those regions could raise sea levels and cause flooding in
low-lying parts of the world.
The loss of ice in
Patagonia, as with much of the ice retreating
worldwide, is largely a response to natural warming that has
occurred since the end of the Little Ice Age more than a
century ago. But the rate of ice loss seems to be accelerating
with time, suggesting that more recent climate changes or
unknown ice dynamics may play a role as well, Rignot said.
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