Researchers from America and Europe have combined to provide the clearest account yet of how much glacial ice flows into the sea following the collapse of an Antarctic ice shelf.
The research combines data from NASA and the French space agency CNES, along with measurements collected during aircraft missions, and details recent ice losses while promising to sharpen future predictions of further ice loss and sea level rise. The study was published online July 25 in the Journal of Glaciology.
“Not only do you get an initial loss of glacial ice when adjacent ice shelves collapse, but you get continued ice losses for many years — even decades — to come,” says Christopher Shuman, lead author of the study and a researcher at UMBC’s Joint Center for Earth Systems Technology (JCET) at NASA’s Goddard Space Flight Center, Greenbelt. “This further demonstrates how important ice shelves are to Antarctic glaciers.”
Previous research showed that the collapse of several Antarctic ice shelves – long tongues of ice which are fed by a glacier and extend into the sea off the main land mass – increased the acceleration of the glaciers that fed into them, thereby losing not only the ice shelf, but speed the loss of the glacier itself.
The researchers detailed ice loss maps from 2001 to 2009 for the main tributary glaciers of the Larsen A and B ice shelves, which collapsed in 1995 and 2002 respectively, and showed that the loss of ice took place at a rate of at least 11.2 gigatons (11.2 billion tons) per year from 2001 to 2006.
Their ongoing work shows a similar rate of ice loss. 2006 to 2010 averaged 10.2 gigatons (10.2 billion tons) per year.
In addition, the analysis revealed a rapid decrease in the elevation of some glaciers of more than 500 feet, “and it puts the total ice loss from 2001 to 2006 squarely between the widely varying and less certain estimates produced using an approach that relies on assumptions about a glacier’s mass budget.”
Source: NASA Goddard Space Flight Center
Image Credits: MODIS, NASA’s Earth Observatory and LIMA