Greenland Ice-Loss Doubles in Past Decade
The loss of ice from and around Greenland doubled between 1996 and 2005, because glaciers in the area were flowing faster into the ocean in response to a generally warmer climate, according to a recent study.
The study concludes that changes to Greenland’s glaciers in the past decade are widespread, large and sustained over time. They are progressively affecting the entire ice sheet and increasing its contribution to global sea level rise.
Researchers Eric Rignot of the National Aeronautics and Space Administration’s Jet Propulsion Laboratory and Pannir Kanagaratnam of the University of Kansas Center for Remote Sensing of Ice Sheets used satellite data to conduct a survey of Greenland glacial ice discharge rates at different times throughout the past 10 years.
According to the researchers, the evolution of Greenland’s ice sheet is being driven by several factors. These include accumulation of snow in its interior, melting of ice along its edges and the flow of ice into the sea from outlet glaciers along its edges. This study focuses on glacial ice flow.
The researchers theorized if glacier acceleration is an important factor in the evolution of the Greenland ice sheet, its contribution to sea level rise was being underestimated.
To test this theory, the scientists measured ice velocity with interferometric synthetic aperture radar data collected by the European Space Agency’s Earth Remote Sensing Satellites 1 and 2 in 1996, the Canadian Space Agency’s RADARSAT-I in 2000 and 2005, and the European Space Agency’s Envisat advanced synthetic aperture radar in 2005.
They combined the ice velocity data with ice sheet thickness data from airborne measurements made between 1997 and 2005 to calculate the volumes of ice transported to the ocean by glaciers and how they changed over time.
From 1996 to 2000, widespread glacial acceleration was found at latitudes below 66° north. This acceleration extended to 70° north by 2005. The researchers estimated the ice mass loss resulting from enhanced glacier flow increased from 63 cubic kilometers in 1996 to 162 cubic kilometers in 2005.
Combined with the increase in ice melt and in snow accumulation over that same time period, they determined the total ice loss from the ice sheet increased from 96 cubic kilometers in 1996 to 220 cubic kilometers in 2005. /st/
Copyright Compass Publications, Inc. Mar 2006
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