for National Geographic News
The Greenland ice sheet is melting three times faster today than it was five years ago, according to a new study.
The finding adds to evidence of increased global warming in recent years and indicates that melting polar ice sheets are pushing sea levels higher, the authors report.
According to the study, Greenland ice loss now amounts to more than 48 cubic miles (200 cubic kilometers) each year.
"Significant melting has a significant impact on sea level rise," said Jianli Chen, a research scientist at the University of Texas at Austin who led the study.
The finding, reported today by the online edition of the journal Science, closely agrees with another study on the rapid wasting of Greenland's glaciers published in the journal in February.
Both studies suggest the shrinking ice sheet now contributes about 0.02 inch (0.5 millimeter) a year to global sea level rise.
"That's a very big number," Chen said.
Losses and Gains
Global sea levels have risen by about 0.1 inch (2.8 millimeters) a year over the past decade.
If all the ice on Greenland were to melt into the North Atlantic Ocean, global sea levels would rise by about 21.3 feet (6.5 meters).
Thus scientists are keen to understand if the Danish-owned Arctic island (Greenland map) is losing more ice mass through melting and discharge of glaciers than it is gaining from fresh snowfall.
Richard Alley is a glaciologist at Pennsylvania State University in University Park who was not involved with the study.
SOURCES AND RELATED WEB SITES