December
11, 2006 More than half of
the estimated
650 billion tons of ice lost to the oceans annually comes from the
discharge of
small glaciers and icecaps, said Professor Tad Pfeffer of
CU-Boulder’s Earth’s
sea level currently is
rising at about 3 millimeters per year and could rise by several feet
or more
by the end of the century if warming on Earth continues, according to
recent
studies. Most scientists believe rising temperatures are primarily the
result
of a continuing build-up of greenhouse gases in the atmosphere. "The message from
our study
is that small glaciers and ice caps are the biggest sources of water in
global
sea rise, which runs contrary to many news reports focusing on
Antarctica and
Greenland," said Pfeffer, an INSTAAR fellow and professor in the civil,
environmental and architectural engineering department. "We feel that
ignoring the contributions of small glaciers and icecaps is dangerous
because
it affects the accuracy of predictions of sea rise around the world." Pfeffer made a
presentation on
disappearing glacial ice at the Fall Meeting of the American
Geophysical Union
held in Meier estimated
there are several
hundred thousand small glaciers and small, pancake-shaped ice masses
known as
ice caps spread around the world in polar and temperate regions, which
because
of their numbers are extremely difficult to map and monitor
individually. They
range from modest, high mountain glaciers found on every continent to
huge
glaciers like the Bering Glacier in Because of the
challenge in
inventorying each individual glacier, the researchers used a
mathematical
"scaling" process to estimate and characterize more remote glacier
volumes, thicknesses and trends by factoring in data like altitude,
climate and
geography, said Meier. The team used data gathered from around the
world,
including cold regions in The analysis by the
CU-Boulder
team includes tidewater glaciers like the Columbia Glacier, one of 51
Alaskan
glaciers that empty into the ocean. A 2005 study by Pfeffer, Meier and
colleagues showed the Columbia Glacier -- the largest glacial
contributor to
sea level in North America – had shrunk by 9 miles since 1980
and was
discharging two cubic miles of ice into "We expect that
small
glaciers will be the biggest contributors to global sea rise for the
next 50 to
100 years," said Meier. Continued warming temperatures will likely
cause
most of the glaciers in the Rocky Mountains and Pfeffer said he
hopes policy
makers pay attention to studies calculating the large contributions to
sea rise
from small glaciers and ice caps. "I don’t think we can
afford to wait
until there is two feet of water in our livings rooms to start thinking
about a
response to changing climate," he said. In addition to sea
rise
contributions, increasingly large discharges of fresh water into the
oceans
from glaciers and ice caps also may be having ecological impacts in
coastal
regions, including coastal
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