Antarctica Melt Has Accelerated 280 Percent in Past 40 Years

Antarctica Melt Has Accelerated 280 Percent in Past 40 Years

Antarctica Melt Has Accelerated 280 Percent in Past 40 Years

Researchers then subtracted the amount of snowfall from the amount of ice lost to sea to determine Antarctica sends six times more ice into the sea each year than it did in 1979. Global sea levels have already risen seven to eight inches since 1900. But in recent years, there has been growing concern that the Antarctic could push that even higher.

Warming ocean water will only speed up ice loss in the future, and experts say sea levels will continue to mount for centuries, no matter what humans do now to rein in climate change.

Richard Levy said that the study confirmed a connection between these astronomical changes and changes in the size and extent of the Antarctic ice sheet.

This 2016 photo provided by NASA shows the Getz Ice Shelf.

Currently, the Antarctic ice sheet holds about 90 percent of the world's ice, and if it were all to melt, sea level would rise some 240 feet, according to the U.S. Geological Survey.

"This study adds to our knowledge of the history and behaviour of Antarctica's ice sheets and is yet more proof that urgent action is needed on emissions", said co-author Professor Tim Naish, of Victoria University's Antarctic Research Centre. Forams living in the deep ocean accumulate isotopes in their shells, and different isotopes of oxygen can yield a detailed chemical record of the changing volumes of the Antarctic Ice Sheet. Researchers believe the accelerated melt could cause sea levels to rise at a quicker rate than predicted in coming years.

The research is important because it teases out the pattern of growth and decay of the ice sheet over geologic time, including the presence of sea ice, a thin and fragile layer of frozen ocean surrounding Antarctica.

The team was able to discern that between 1979 and 1990, Antarctica shed an average of 40 gigatons of ice mass annually. That includes Cook and Ninnis, which are the gateway to the massive Wilkes Subglacial Basin, and other glaciers known as Dibble, Frost, Holmes and Denman. (A gigaton is 1 billion tons.) From 2009 to 2017, about 252 gigatons per year were lost. And it remains alarmingly vulnerable.

The new research is consistent in some ways with a major study published previous year by a team of 80 scientists finding that Antarctic ice losses have tripled in a decade and now total 219 billion tons annually. "If we fail to achieve carbon dioxide emissions targets and Earth's average temperature warms more than 2 degrees Celsius, sea ice will diminish and we jump into a world that is more similar to that last experienced during the early to mid-Miocene", says Levy, referencing a geological epoch that ended about 14 million years ago when the Earth and its polar regions were much more temperate, with an atmosphere supercharged with carbon dioxide and global temperatures, on average, warmer by 3 to 4 degrees Celsius (7 to 9 degrees Fahrenheit). In particular, Rignot says, key parts of East Antarctica, which has been the subject of less focus from researchers in the past, need a much closer look, and fast.

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