An article from NASA updated a few days ago shows that a 2015 study has shown that the issue of the Antarctica Ice Sheet melting isn’t quite so grim as it may have appeared. It seems that, while it is true that large areas of the continent have lost some of their mass, Antarctica is continually accumulating ice.
Furthermore, another more recent study done by the same organization has proved that the continent’s continual increase in mass is due to a 10,000-year-old process that is still adding enough ice and snow to counteract the effects of global warming.
This directly challenges the results of other studies, such as the 2013 report of the Intergovernmental Panel on Climate Change, according to which the overall mass of Antarctica is continually reducing.
Satellite data has shown that the continent’s ice mass has increased from 1992 to 2001, by an average of 112 billion tons per year. An increase which has slowed to 82 billion between 2003 and 2008.
In order to determine the changes in mass, scientists analyze whether the amount of snow that falls on an ice sheet is equal or not to the amount of ice that flows downward or outward to the ocean. In order to do this, they measure the changes in surface height and then calculate the continent’s increase or decrease in mass.
However, Jay Zwally, a glaciologist working for the NASA Goddard Space Flight Center in Greenbelt, Maryland, has argued that if the speed at which the Antarctic Peninsula and areas of West Antarctica continues to increase, it may soon surpass the ice gain that can be seen in East Antarctica. According to his estimates, this change could happen in the next 20 or 30 years.
In his study regarding the changes in the surface height of the continent’s ice sheet, Zwally has used data collected by altimeters on two European Space Agency ERS satellites during periods spanning from 1992 to 2001, as well as information gathered through the laser altimeter found o NASA’s ICESat between 2003 and 2008.
The scientist said that, unlike in other studies, his team used meteorological data gathered starting with 1979 in order to prove the fact that the of snowfall that East Antarctica has seen yearly has decreased by over 10 billion tons between the periods measured by the ERS and ICESat.
The team also showed that the yearly mass gain that has occurred over the last 10.000 years has remained constant between 1992 and 2008, at 200 billion tons. However, the ice losses in the Antarctic Peninsula and areas of West Antarctica have increased by 65 billion tons per year.
Zwally also noted that the ice losses that are seen in Antarctica currently have no influence in the rising of the sea level. “But this is also bad news. 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”, the scientist added.
While this report shows that the situation in Antarctica may not be as bad as others may have suggested, it is also a testament to how difficult it is to measure the changes in ice height, in East Antarctica.
In order to increase the accuracy of future studies, NASA is developing ICESat-2. This successor to the original ICESat project is set to launch in 2018 and will be equipped with better, more precise sensors.
