NASA reported that the Antarctic's ice gain is greater than its loss, based on the study published in the Journal of Glaciology on Oct. 29. The NASA report challenged many climate change studies, including that of the United Nations' Intergovernmental Panel on Climate Change, which showed the southern continent is suffering a continuous loss of land ice.
In NASA's report, a team of researchers found that from 1992 to 2001, Antarctica had a net gain of 112 billion tons of ice annually but slowed to 82 billion tons per year from 2003 to 2008. In the paper, NASA glaciologist and lead study author Jay Zwally wrote that Antarctica's ice melt would take several decades to outweigh the ice growth.
The conflicting reports now raise the question whether climate change is finally beginning to wane. Zwally's team expressed that the NASA findings are contesting the current explanation for the rising sea levels, much of which are linked to the melting ice in Antarctica and Greenland.
The Antarctic's ice sheet data was collected using NASA's Ice, Cloud and Land Elevation Satellite (ICESat) as part of the Earth Observing System program. Launched in January 2003, ICESat was created to generate the data needed to evaluate ice sheet mass balance. It also provides data on cloud property, focusing on stratospheric clouds at the poles.
However, climate scientists expressed concerns that NASA's findings do not prove that global warming is over. They noted that improved tools are needed to measure Antarctica's ice height.
"Doing altimetry accurately for very large areas is extraordinarily difficult, and there are measurements of snow accumulation that need to be done independently to understand what's happening in these places," said glaciologist Ben Smith from the University of Washington in Seattle. Smith was not part of the NASA study.
ICESat is capable of providing incredibly accurate data, but for greater accuracy, NASA is building the ICESat mission's successor - ICESat-2. Set to launch in 2018, the new satellite will calculate the ice sheet measurement changes within a No. 2 pencil's thickness.
"It will contribute to solving the problem of Antarctica's mass balance by providing a long-term record of elevation changes," said ICESat-2 deputy project scientist and glaciologist Tom Neumann from NASA's Goddard Space Flight Center.
