Dramatic Ice Loss Spreads to Northwest Coast of Greenland

Scientists report that the loss of ice from Greenland, previously documented in the south of the island, has spread rapidly since 2005 to the northwest coast. "These changes on the Greenland ice sheet are happening fast, and we are definitely losing more ice mass than we had anticipated," says Isabella Velicogna, one of the researchers. "We also are seeing this trend in Antarctica, a sign that warming temperatures really are having an effect on ice in Earth's cold regions."

About 20 percent of the world's ice is frozen atop Greenland.  If it melted entirely it would elevate sea levels by about 21 feet.  Research published last year indicated that Greenland lost about 1,605 cubic kilometers (385 cubic miles) of ice between April 2002 and February 2009.  Meanwhile, air temperatures are warming over the ice -- 2.2 degrees Celsius (4 degrees Fahrenheit) since 1991.

The scientists based their latest conclusions on data from NASA's Gravity and Recovery Climate Experiment (GRACE) satellite system; and from global positioning system (GPS) measurements generated by instruments on bedrock on the edges of the ice sheet.  Their findings were presented in Spread of ice mass loss into northwest Greenland observed by GRACE and GPS, published in the 19 March 2010 issue of Geophysical Research Letters.   The research was funded by NASA and the National Science Foundation (NSF).

Orbiting Twins - The GRACE satellites
Orbiting Twins - The GRACE satellites.  Source: NASA.

"Our speculation is that some of the big glaciers in this region are sliding downhill faster and dumping more ice in the ocean," says one of the authors, John Wahr.  Shfaqat Abbas Khan, lead author of the article, says: "If this activity in northwest Greenland continues and really accelerates some of the major glaciers in the area -- like the Humboldt Glacier and the Petermann Glacier -- Greenland's total ice loss could easily be increased by an additional 50 to 100 cubic kilometers (12 to 24 cubic miles) within a few years." [emphasis added]

Dr. David Carlson, Director of the International Polar Year International Program Office said in a statement before the Senate Foreign Relations Committee hearing on "The Global Implications of a Warming Arctic" in May 5, 2009:  “A clear consensus has emerged during IPY [International Polar Year] that the Greenland Ice sheet will disappear as a consequence of this current global warming.”  Carlson added that a “very plausible outcome” was “a meter or more of sea level rise in this century from Greenland alone.” 

Above: The animation shows the spread of ice loss into northwest Greenland observed by NASA's Gravity and Recovery Climate Experiment (GRACE) satellite
system 
from 2003 through 2009. The shift in the color spectrum beginning with turquoise and ending in black over the seven-year time span shows the decreasing mass of ice relative to 2003. Courtesy John Wahr, University of Colorado.

Online Resources

Animations of the GRACE mission.

Spread of ice mass loss into northwest Greenland observed by GRACE and GPS. By Shfaqat Abbas Khan, John Wahr, Michael Bevis, Eric Kendrick and Isabella Velicogna in Geophysical Research Letters, vol. 37 (19 March 2010).

Ice loss from Greenland ice sheet spreading to northwest coast.  Press release (23 March 2010) from the American Geophysical Union. 

New study of Greenland under “more realistic forcings” concludes “collapse of the ice-sheet was found to occur between 400 and 560 ppm” of CO2.  Climate Progress (23 March 2010)

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