A new study revealed that the polar ice sheets in Antarctica and Greenland are melting at a rapid rate, adding nearly half an inch to sea water levels in the past 20 years. According to the study, polar ice sheets are melting at a three-times faster rate than they were in the 1990s, with most of the loss occurring in Greenland.
Lead study co-author Andrew Shepherd of the University of Leeds in Britain told reporters, “This improved certainty allows us to say definitively that both Antarctica and Greenland have been losing ice.”
Going through past estimates of sea level rising due to polar ice sheet melting since 1989, the team of researchers found that melted ice sheets have added an average of 0.023 in (0.59 mm) to sea-level rise since 1992, with an uncertainty of 0.008 (0.2 mm) per year, TIME reported. The study found that when averaged over the past 20 years, ice sheet melting has contributed to nearly 20 percent of overall sea level rising and nearly doubling in the past couple of years.
According to NBC News, the study, which was published in the journal Science, was based on information from 47 experts at 26 institutes that had published earlier studies. The estimates found in the past varied greatly due to data stating that Antarctica’s vast eastern ice sheet was adding ice instead of losing it, researchers said.
Fellow study co-author Erik Ivins, a satellite data expert with NASA’s Jet Propulsion Lab, added that eastern Antarctica has added ice, but that the continent has shown a “50 percent increase in ice loss rate” over the past decade. NBC News reported that most of the loss is found in western Antarctica, such as Pine Island Glacier.
In Greenland, Ivins said that ice sheets are “losing mass at about five times the rate today as it was in the early 1990s.” The study found that Greenland’s melt rate has increased from 55 billion tons a year in the 1990s to almost 290 billion tons a year in recent years.
What is more troubling is what will happen to the polar ice caps in the future, and whether or not melting will continue to accelerate. Ian Joughin, a glaciologist at the University of Washington in Seattle who collaborated on the study, told Live Science, “It really remains unclear whether such losses will decline, whether it will level off or whether they will accelerate further.”
He added, “To understand what is going to happen in the next century, we need models—and right now those models are very much limited by lack of data.”
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