An increase in Antarctic snow accumulation that began 10,000
years ago is currently adding enough ice to the continent to
outweigh the increased losses from its thinning glaciers.
Areas of the continent like the Antarctic peninsula have
increased their mass loss in the last decades, says a new NASA
study.
The research challenges the conclusion of other studies,
including Intergovernmental Panel on Climate Change’s 2013
report which says that Antarctica is overall losing land ice.
According to the analysis of satellite data, the Antarctic ice
sheet showed a net gain of 112 billion tonnes of ice a year from
1992 to 2001. The net gain slowed to 82 billion tonnes of ice
per year between 2003 and 2008.
“We are 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,” explained
Jay Zwally, glaciologist with NASA Goddard Space Flight Centre
in Greenbelt, Maryland.
Our main disagreement is for East Antarctica and the interior of
West Antarctica.
“Here, we see an ice gain that exceeds the losses in the other
areas,” he added.
But it might take a few decades for Antarctica’s growth to
reverse, according to Zwally.
The study analysed changes in the surface height of the
Antarctic ice sheet measured by radar altimeters on two European
Space Agency satellites and by the laser altimeter on NASA’s
Ice, Cloud, and land Elevation Satellite (ICESat).
“At the end of the last Ice Age, the air became warmer and
carried more moisture across the continent, doubling the amount
of snow dropped on the ice sheet,” Zwally noted.
“The good news is that Antarctica is not currently contributing
to sea level rise, but is taking 0.23 mm per year away,” Zwally
said. But this is also bad news.
“If the 0.27 mm per year 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,” he pointed out in the study
appeared in the Journal of Glaciology .IANS
http://www.thehindu.com/todays-paper/tp-in-school/antarctica-is-
gaining-ice-nasa/article7834602.ece