Earth Science

Wasting Away

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Science  26 Nov 2004:
Vol. 306, Issue 5701, pp. 1441
DOI: 10.1126/science.306.5701.1441a

The mountainous regions of the world are estimated to harbor approximately 160,000 glaciers. They are recognized as being sensitive indicators of global warming, and, if they were to melt, the sea level would rise significantly. Because of their remote location or large size, it has been difficult to accurately measure many of these glaciers and hence hard to say how fast they may be receding.

Using digitized glacier outlines inferred from satellite data from 1985 to 1999, Paul et al. circumvent these difficulties and calculate the change in area of about 930 glaciers in the Swiss Glacier Inventory 2000. They find that these glaciers have lost about 18% of their cumulative area during that period, which means that they disappeared at a rate seven times higher than the averaged rate from 1850 to 1973. The variety in the patterns of glacier disintegration observed indicates that massive downwasting (thinning) has been the major mechanism of loss, rather than a dynamic response to climate warming. Even faster rates of loss in the future are forecast, due in part to a delayed response of glaciers to the extraordinarily warm years during the 1990s and the early 2000s. — HJS

Geophys. Res. Lett. 31, L21402 (2004).


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