by Playfuls Staff |
12th August 2006
National Geographic reported that the immense ice cover that spreads all over Greenland is melting at a faster rate than previously measured, approximately three times faster than five years ago.[more]
Using time-variable gravity measurements from the Gravity Recovery and Climate Experiment (GRACE) satellite mission, the scientist estimated that ice mass changes over Greenland during the period April 2002 to November 2005.
After correcting for effects of spatial filtering and limited resolution of GRACE data, estimated total ice melting rate over Greenland was found to be -239 ± 23 cubic kilometers per year, mostly from East Greenland.
The team of researchers said this estimate agrees remarkably well with another recent assessment of -224 ± 41 cubic kilometers per year, based on satellite radar interferometry data.
GRACE estimates in southeast Greenland suggest accelerated melting since the summer of 2004, consistent with the latest remote sensing measurements.
The bad news is that the ice melting is continuously accelerating, and this poses a great risk for coastal regions. By the time all the ice melts from Greenland, the oceans’ level will increase by 6.5 meters, which would totally wipe out many islands and countries situated under sea-level (like the Netherlands or some parts of Japan). Even worse, the entire climate on Earth would be seriously affected by this accelerated melting.
When glaciers begin to melt, water works its way down to the bottom of the ice. There it lubricates the glacier, which will pick up its downhill pace. This is why the process of “ice-extinction” is accelerating: huge amounts of ice plummet in the ocean before their actual “life-span”, because their basis is melting.
Greenland is considered the second largest reservoir of fresh water on Earth with about 10 percent of the world's fresh water. The amount of fresh water poured into ocean from Greenland’s ice could add 0.56 millimeters annually to a global increase in sea levels, higher than all previously published measurements.
"Our latest findings are the most complete measurement of ice mass loss for Greenland," said Byron Tapley, director of the university's Center for Space Research and senior author of the study.
"The sobering thing to see is that the whole process of glacial melting is stepping up much more rapidly than before," he added in a statement.
Josefino Comiso, a senior research scientist at NASA's Goddard Space Flight Center in Greenbelt, Maryland, is on the side of the researchers who came up with the study, but is cautious when it comes to pulling the conclusions.
"The data record of a little more than three years is really not robust enough to enable an accurate assessment of a trend or an acceleration," he says.
He also added that the findings could be the result of the abnormally warm past 4 years, after which weather could eventually return to its previous state.
Myron Ebell, director of energy and global warming policy at the libertarian Competitive Enterprise Institute, questioned why scientists are drawing broad conclusions from data covering such a short time span.
"We now have 'the sky is falling down' on the basis of a few years of data," said Ebell, whose group is partly funded by the fossil-fuel industry.
"If enough fresh water enters the Norwegian Current and you interrupt return flow, then there could be climate effects in Europe," said Byron Tapley, one of Chen's co-authors.
