Antarctic losing 500% more ice a year than in 80s, Nasa study says

  15 January 2019    Read: 1004
 Antarctic losing 500% more ice a year than in 80s, Nasa study says

The Antarctic ice sheet is losing six times as much ice each year as it was in the 1980s and the pace is accelerating, one of the most comprehensive studies of climate change effects on the continent has shown.

More than half an inch has been added to global sea levels since 1979, but if current trends continue it will be responsible for metres more in future, the Nasa-funded study found.

The international effort used aerial photos, satellite data and climate models dating back to the 1970s across18 Antarctic regions to get the most complete picture to date on the impacts of the changing climate.

It found that between 1979 and 1990 Antarctica lost an average of 40 gigatonnes (40 billion tonnes) of its mass each year.

Between 2009 and 2017 it lost an average 252 gigatonnes a year. This has added 3.6mm per decade to sea levels, or around 14mm since 1979, the study shows.

“That’s just the tip of the iceberg, so to speak,” Professor Eric Rignot from University of California, Irvine and lead author of the study published in Nature Geoscience. “As the Antarctic ice sheet continues to melt away, we expect multi-metre sea level rise from Antarctica in the coming centuries.”

The new analysis provides a breakdown of how ice losses in different sectors of Antarctica have changed and helps address confusion that has led to some climate change sceptics claiming the Antarctic ice mass is growing.

While western Antarctica has had some of the most visible ice loss, particularly to the extent of its sea ice, some studies have suggested that ice coverage is increasing in eastern Antarctica fast enough to cancel this out.

The latest study shows that east Antarctica ice loss has been a significant contributor to sea level rises, and called for more research on the factors that affect this.

“The Wilkes Land sector of east Antarctica has, overall, always been an important participant in the mass loss, even as far back as the 1980s, as our research has shown,” Professor Rignot said. “This region is probably more sensitive to climate than has traditionally been assumed, and that’s important to know, because it holds even more ice than west Antarctica and the Antarctic peninsula together.”

The researchers found no significant change in snow fall across the continent, but sea level warming has been driving the accelerating ice loss by speeding up the rate that glaciers around the continents edges are melting.

“As climate warming and ozone depletion send more ocean heat toward those sectors, they will continue to contribute to sea level rise from Antarctica in decades to come,” said Professor Rignot.

 

The Independent


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