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Rapid Wastage of Alaska Glaciers and Their Contribution to Rising Sea Level
Anthony A. Arendt,Keith A. Echelmeyer,William D. Harrison,Craig S. Lingle,Virginia B. Valentine
We have used airborne laser altimetry to estimate volume changes of
67 glaciers in Alaska from the mid-1950s to the mid-1990s.The average
rate of thickness change of these glaciers was -0.52m/year.
Extrapolation to all glaciers in Alaska yields an estimatedtotal
annual volume change of -52 ± 15 km3/year (water
equivalent), equivalent to a rise in sea level (SLE)of 0.14 ± 0.04 mm/year. Repeat measurements of 28 glaciers fromthe mid-1990s to
2000-2001 suggest an increased average rate ofthinning, -1.8 m/year.
This leads to an extrapolated annual volumeloss from Alaska glaciers
equal to -96 ± 35 km3/year, or 0.27 ± 0.10 mm/year SLE, during the past decade. Theserecent losses are nearly
double the estimated annual loss fromthe entire Greenland Ice Sheet
during the same time period andare much higher than previously
published loss estimates for Alaskaglaciers. They form the largest
glaciological contribution torising sea level yet measured.
Geophysical Institute, University of Alaska, 903 Koyukuk Drive,
Post Office Box 757320, Fairbanks, AK 99775, USA.
To whom correspondence should be addressed: E-mail:
arendta{at}gi.alaska.edu
