A new NASA study found Antarctic snow accumulation over the last 10,000 years is adding enough ice to outweigh the continent’s loss of glacier ice. However, the findings don’t mean the region is safe from climate change.
“We’re essentially in agreement with other studies that show an increase in ice discharge in the Antarctic Peninsula and the Thwaites and Pine Island region of West Antarctica,” said Jay Zwally, a glaciologist with the NASA Goddard Space Flight Center. “Our main disagreement is for East Antarctica and the interior of West Antarctica—there, we see an ice gain that exceeds the losses in the other areas.”
The new analysis of satellite data shows the Antarctic ice sheet had a net gain of 112 billion tons of ice per year from 1992 to 2001. Between 2003 and 2008, the net gain lowered to 82 billion tons of ice per year.
Since it began accumulating 10,000 years ago, the snowfall has thickened the affected region of the continent by an average of 0.7 in/yr.
According to NASA, the researchers analyzed changes in the surface height of the Antarctic ice sheet, which were measured by radar altimeters on two European Space Agency European Remote Sensing (ERS) satellites between 1992 and 2001, and by the laser altimeter on NASA’s Ice, Cloud and land Elevation Satellite (ICESat) from 2003 to 2008.
The findings buck conclusions from the Intergovernmental Panel on Climate Change (IPCC)’s 2013 report that Antarctica is losing land ice overall.
“The good news is that Antarctica is not currently contributing to sea level rise, but is taking 0.23 mm/yr away,” Zally said, who is the lead author of a paper on the subject appearing in Journal of Glaciology. “But this is also bad news. If the 0.27 mm/yr of sea level rise attributed to Antarctica in the IPCC report is not really coming from Antarctica, there must be some other contribution to sea level rise that is not accounted for.”
Further, if ice losses in the Antarctic Peninsula and areas of West Antarctica continue to increase at the same rate as the last two decades, the losses will catch up with the long-term gains in East Antarctica within 20 to 30 years, according to Zwally.
“I don’t think there will be enough snowfall increase to offset these losses,” Zwally said.
In order to help more accurately measure changes in ice thickness, NASA is developing the ICESat-2, scheduled to launch in 2018. “ICESat-2 will measure changes in the ice sheet within the thickness of a No. 2 pencil,” said glaciologist Tom Neumann, who is the deputy project scientist for ICESat-2.
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