Author: Laurel Hamers / Source: Science News for Students
Antarctica’s ice is melting faster and faster. In the past five years, the frozen continent has lost ice three times faster, on average, than it did over the previous 20 years.
An international team of scientists has made the most thorough analysis yet of Antarctica’s ice sheet mass. They combined data from two dozen satellite surveys for their study. The conclusion: The frozen continent lost an estimated 2,720 billion metric tons (3 trillion tons) of ice from 1992 to 2017. Most of that loss happened in recent years, particularly in West Antarctica.
Before 2012, the continent lost an average of 76 billion metric tons (84 billion tons) of ice each year. But from 2012 to 2017, the rate increased to 219 billion metric tons (241 billion tons) per year.
Combined, all that water raised the world’s sea level by an average of 7.6 millimeters (0.3 inch). Two-fifths of that rise happened in the last five years. That increase in melting is helping scientists understand how the Antarctic ice sheet is responding to climate change. The researchers report their results in the June 14 Nature.
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Measuring melt
Before this study, Antarctica’s ice loss seemed to be on the low end of international predictions, says Andrew Shepherd. He’s an earth scientist at the University of Leeds in England and one of the study’s authors. “Now it’s tracking the upper end” of those estimates, he says.
Antarctica currently holds enough frozen water to raise the world’s oceans by 58 meters (190 feet). The sea is already rising, and melting ice from Antarctica is a major reason. That rising sea level is threatening coastal communities and ecosystems around the world with flooding. A good estimate of Antarctica’s ice loss will help climate scientists predict future sea level rise, Shepherd says, as the planet keeps warming.
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