Doyle Rice, USA TODAY
Published 3:23 p.m. ET March 16, 2020 | Updated 4:17 p.m. ET March 16, 2020
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Greenland and Antarctica have lost 6.4 trillion tons of ice in the past three decades; unabated, this rate of melting could cause flooding that affects hundreds of millions of people by the end of the century, NASA said in a statement.
Satellite observations showed that the regions are losing ice six times faster than they were in the 1990s, according to a new study.
If the current melting trend continues, the regions will be on track to match the “worst-case” scenario of the Intergovernmental Panel on Climate Change (IPCC) of an extra 6.7 inches of sea level rise by 2100.
“That’s not a good news story,” study lead author Andrew Shepherd from the University of Leeds in the United Kingdom, told the BBC.
Scientists said that the two ice sheets together lost 81 billion tons per year in the 1990s, compared with 475 billion tons of ice per year in the 2010’s – a whopping sixfold increase.
“Today, the ice sheets contribute about a third of all sea-level rise, whereas in the 1990s, their contribution was actually pretty small at about 5%,” Shepherd told the BBC. “This has important implications for the future, for coastal flooding and erosion.
The resulting meltwater boosted global sea levels by 0.7 inch. Of this total sea-level rise, 60% resulted from Greenland’s ice loss and 40% resulted from Antarctica’s.
The findings were published by an international team of 89 polar scientists from 50 organizations, and are the most comprehensive assessment to date of the changing ice sheets, NASA said.
While it’s true that the seas have risen and fallen before, what’s new is the enormity of coastal development around the world that will need to be protected, moved or abandoned due to sea-level rise from human-caused global warming.
Sea level has risen nearly 8 inches worldwide since 1880 but, unlike water in a bathtub, it doesn’t rise evenly. In the past 100 years, it has climbed about a foot or more in some U.S. cities because of ocean currents and land subsidence.
“Every centimeter of sea-level rise leads to coastal flooding and coastal erosion, disrupting people’s lives around the planet,” said Shepherd.
The study was published last week in the peer-reviewed British journal Nature.
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