Antarctica Loses Trillions of Tons of Ice Since 1992, Report Reveals

Audrey Hill
June 15, 2018

From 2012 to 2017, the melt rate increased to more than 241 billion tons a year, according to the study in the journal Nature published yesterday.

From 1992 to 2011, Antarctica lost almost 84 billion tons of ice a year (76 billion metric tons).

Estimated annual ice loss from the Antarctic Peninsula rose from 7 billion to 33 billion metric tons over the same 25-year period, due to ice shelf collapse.

But 40 per cent of that increase came from the last five years of the study period, from 2012 to 2017, when the ice-loss rate accelerated by 165 per cent.

The analysis suggests that 3 trillion tons' worth of Antarctic ice losses have increased global sea levels by 7.6 mm (0.3 inches) since 1992, and that the increase is accelerating.

"The work is consistent with previous studies indicating massive losses of ice in West Antarctica and on the Antarctic Peninsula, but it brings the estimates up to date and confirms that they are significant", Bethan Davies, a lecturer at the University of London who wasn't involved with the study, told Earther.

Up to now, scientists have struggled in determining whether Antarctica has accumulated more mass through snowfall than it loses in meltwater run-off and ice flows into the ocean.

"The continent is causing sea levels to rise faster today than at any time in the past 25 years". This roughly suggests that Antarctica glacial melting is now adding about 0.5 millimeters per year to sea level rise.

However, the role of sea ice in buffering ice shelves and continental ice sheets is rarely factored into Antarctic ice-loss modelling, according to lead researcher Dr Rob Massom from the Australian Antarctic Institute.

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The result also reinforces that nations have a short window - perhaps no more than a decade - to cut greenhouse gas emissions if they hope to avert some of the worst consequences of climate change.

"That's a big jump, and it did catch us all by surprise", Shepherd says.

More than 70% of the recent melt is in West Antarctica.

More than 90 percent of that frozen water sits atop East Antarctica, which has remained mostly stable even as climate change has driven up Earth's average surface temperature by a full degree Celsius (1.8 degrees Fahrenheit). "Thanks to the satellites our space agencies have launched, we can now track their ice losses and global sea level contribution with confidence". "We will not necessarily see exclusively rapid retreat, " said Christianson, noting that as glaciers like Pine Island retreat backwards down a submarine, downhill slope, they will sometimes encounter bumps that slow down their movement.

"This has to be a cause for concern for the governments we trust to protect our coastal cities and communities", he said.

"Around Brooklyn you get flooding once a year or so, but if you raise sea level by 15 centimeters then that's going to happen 20 times a year", said University of Leeds professor Andrew Shepherd, the study's lead author.

The researchers relied on samples taken as part of the worldwide ANtarctic geological DRILLing (ANDRILL) project. If all of the ice in Antarctica melted, global sea levels would rise by more than 190 feet. Sea level rise is a threat to cities from NY to Shanghai as well as low-lying nations from the Pacific Ocean to the Netherlands.

That's because as Antarctica's mass shrinks, the ice sheet's gravitational pull on the ocean relaxes somewhat, and the seas travel back across the globe to pile up far away - with US coasts being one prime destination.

Scientists have previously raised fears about a scenario in which ice loss from Antarctica takes on a rate of explosive growth.

Other reports by MaliBehiribAe

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