Washington, May 17 (ANI): An international group of researchers has confirmed that melting of glaciers caused about one third of the observed sea-level rise, while the ice sheets and thermal expansion of sea water account for one third each.
So far, estimates on the contribution of glaciers have differed substantially. Now 16 scientists from nine countries have compared the data from traditional measurements on the ground with satellite data from the NASA missions ICESat (Ice, Cloud and land Elevation Satellite) and GRACE (Gravity Recovery and Climate Experiment).
Combined with a glacier inventory that is available globally for the first time, the researchers were able to determine the glacier mass changes all over the world much more accurately than before.
The extrapolations of local field measurements to large regions and entire mountain ranges traditionally applied sometimes overestimated the ice loss, said University of Zurich geographer Frank Paul.
And his fellow colleague Tobias Bolch added "We are well aware of the weaknesses of the individual satellite methods. However, in highly glacierized regions the results obtained using the two different methods agree well. With the mix of methods that have now been tested and applied, we have come a major step closer to determining glacier mass loss with higher precision."
The results show that almost all glacier regions lost mass in the years 2003 to 2009, most of all in Arctic Canada, Alaska, coastal Greenland, the southern Andes and in the Himalayas.
By contrast, the glaciers in Antarctica - smaller ice masses that are not connected to the ice sheet - made scarcely any contribution to sea-level rise during this period.
This finding deviates significantly from previous estimates, saying that the Antarctic glaciers caused around 30 percent of the global ice loss in the period from 1961 to 2004.
"However, neither the periods nor the data basis are directly comparable here," stated Bolch, "so we shouldn't make any premature conclusions in this respect."
Bolch and Paul concluded by recommending that earlier global estimates on the contribution of glaciers to sea-level rise should be revised again.
The results were published in Science. (ANI)
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