The results of a new NASA study show that more ice has been added than lost in Antarctica, contradicting other research.
Studies such as the one carried out by the United Nations’ Intergovernmental Panel on Climate Change had concluded that the overall amount of land ice in Antarctica was declining, but this latest study paints a different picture, writes
Antarctica’s ice gains could be wiped out within a few decades
Researchers from NASA’s Goddard Space Flight Center, the University of Maryland in College Park and the engineering firm Sigma Space Corporation published their results in the Journal of Glaciology on Friday. The team used satellite data to show that 112 billion tons of ice were gained per year from 1992 to 2001 in Antarctica.
Between 2003 and 2008 that gain slowed to 82 billion tons per year. Despite the encouraging results, climate scientists have urged caution in declaring the end of global warming. Rather than demonstrating any great improvement in the situation, it is more proof that measuring the height of ice in Antarctica is a difficult task that requires new and improved tools.
The authors of the study claim that ice melt in Antarctica could outweigh gains within a few decades. “I don’t think there will be enough snowfall increase to offset these losses,” said Jay Zwally, NASA glaciologist and lead author of the study.
Troubling implications for other areas of the globe
Researchers claim that the results of the study call into question current explanations for a rise in sea levels. The prevailing opinion is that melting ice sheets in Greenland and Antarctica are responsible.
“The good news is that Antarctica is not currently contributing to sea level rise, but is taking 0.23 millimeters per year away,” said Dr. Zwally. “But this is also bad news,” he added. “If the 0.27 millimeters 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.”
Study authors point out that measuring small changes in the height of the ice is very difficult, especially in East Antarctica. The largest part of the continent has proven particularly difficult to study, with measurements showing discrepancies with previous data.
“We’re essentially in agreement with other studies that show an increase in ice discharge,” in other parts of the continent, Zwally said. “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,” he explained.
New and improved tools needed for better research
The data used in this study was gathered by radar instruments on European Space Agency satellites from 1992-2001 and laser sensors on a NASA satellite from 2003-2008.
Other studies have claimed that land elevation in East Antarctica has increased, but they claimed it was due to snowfall. Zwally and his team made use of meteorological data from 1979 onward to demonstrate that snow accumulation has been declining and thus thicker ice must be responsible for the increase in elevation.
The team explain that warming air carried more moisture across Antarctica at the end of the last Ice Age around 10,000 years ago, increasing snowfall that then compacted into solid ice.
New tools are being developed that will improve the measurement of ice changes. Due to launch in 2018, “ICESat-2 will measure changes in the ice sheet within the thickness of a No. 2 pencil,” said Tom Neumann, a glaciologist at NASA.