The Antarctic ice sheet is gaining more mass than it is losing, according to recent studies conducted by NASA. Researchers admit some glaciers are indeed thinning. However, snow accumulation continues to offset the loss by increasing the mass of the continent’s overall land ice.
As explained by the National Snow & Ice Data Center, ice sheets, which are also referred to as glacial land ice, are solid masses of ice covering a mass of land. They are specifically defined by their size, which must exceed 20,000 square miles.
Historically, ice sheets covered a large portion of the planet, including the entire continent of North America. However, they were eventually reduced to only two: the Antarctic ice sheet and the Greenland ice sheet.
Although there are only two remaining ice sheets on Earth, they contain an estimated 99 percent of the planet’s fresh water. Therefore, the condition of the Antarctic and Greenland ice sheets is crucial to our survival.
Ice sheets are formed over tens of thousands of years as fallen snow is gradually pressed into thick, dense, layers of ice. Although glacial land ice appears to be a fixed mass, it is in fact “constantly in motion.”
The Antarctic ice sheet is more than 5.4 million square miles and contains an estimated 7.2 million cubic miles of ice. The Greenland ice sheet is 656,000 square miles and contains an estimated 684,000 cubic miles of ice.
The world’s remaining ice sheets are often discussed in conjunction with global warming, as some research suggests glacial land ice is melting at an alarming rate.
A 2013 report, published by the Intergovernmental Panel on Climate Change, concluded that the Antarctic ice sheet has lost an alarming amount of mass with little or no gain. However, studies conducted by NASA contradict earlier findings.
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Goddard Space Flight Center glaciologist Jay Zwally said NASA’s data confirmed that the Antarctic Peninsula, Pine Island region, and Thwaites have experienced “an increase in ice discharge.” However, Zwally said ice gain in East and West Antarctica “exceeds the losses in other areas.”
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Antarctic snow accumulation continues to increase overall ice mass. However, researchers noted the net gain has decreased over the last 14 years.
Between 1992 and 2001, Antarctic glacial land ice increased an estimated 112 billion tons each year. Between 2003 and 2008, the increase was less than 83 billion tons per year.
Thus far, Antarctic ice sheet gains have exceeded any losses overall. However, as the net gain has decreased significantly in the last decade, scientists are concerned. Zwally explains the issue and the potentially negative impact.
“If the losses of the Antarctic Peninsula and parts of West Antarctica continue to increase at the same rate… the losses will catch up with the long-term gain in East Antarctica in 20 or 30 years — I don’t think there will be enough snowfall increase to offset these losses.”
As reported by Science Daily, the new data also disproves theories that runoff from the Antarctic ice sheet is contributing to increases in sea levels. In fact, the NASA research suggests Antarctica is actually decreasing sea levels by 0.23 millimeters each year.
Zwally said the data is specifically disturbing, as “there must be some other contribution to sea level rise that is not accounted for.”
The Antarctic ice sheet data, which was recorded by the Ice, Cloud, and Land Elevation Satellite, or ICESat, is considered to be incredibly accurate. However, data collected by ICESat-2, which is scheduled to launch in 2018, will “measure changes in the ice sheet within the thickness of a No. 2 pencil.”
[Image via Shutterstock/vrihu]