Antarctica lost 3 trillion tonnes of ice in just 25 years


Antarctica lost 3 trillion tonnes of ice in just 25 years

The melting of Antarctica is accelerating at an alarming rate, with about 3 trillion tons of ice disappearing since 1992, an worldwide team of ice experts said in a new study.

From 2012 to 2017, the melting Antarctic ice sheet has dumped 241 billion tons of water into the ocean, the study says. Just one East Antarctic glacier, an enormous mass dubbed Totten, could cause a sea-level rise equal to what could be triggered by the entirety of the West Antarctic sheet, the Washington Post notes.

The planet's largest ice sheet is now losing more than 240 billion tons of ice every year ― a threefold increase from less than a decade ago.

The new findings are the result of the most complete satellite survey of Antarctic ice sheet change to date, involving 84 scientists from 44 worldwide organizations (including NASA and the European Space Agency).

Overall, world sea levels have risen nearly 8 inches in the past century, driven mainly by a natural expansion of water already in the oceans as it warms along with a thaw of glaciers form the Andes to the Alps.

Andrew Shepherd of the University of Leeds, who leads the Ice sheet Mass Balance Inter-comparison Exercise (Imbie), said it had always been suspecting changes in Earth's climate would affect the polar ice sheets.

While the western Antarctica ice sheet has been steadily melting, there has been evidence that East Antarctica itself was stable, or even growing.

However, if emission were low, the ice shelves would remain intact, Antarctica would make a small contribution to sea level rise, and the continent would remain a "natural reserve, dedicated to peace and science" as agreed by Antarctic nations in the late 20th century. Their mission is to produce the most comprehensive look at what's happening to the world's vulnerable ice sheets in Antarctica and Greenland. It's an untenable situation and one that could lead to runaway melt that would raise sea levels more than 10 feet. "This has to be a concern for the governments we trust to protect our coastal cities and communities".

In April, a team of United Kingdom researchers released a report saying that underwater glaciers in Antarctica are melting at an "alarming rate".

"The next piece of the puzzle is to understand the processes driving this change", Durham University's Pippa Whitehouse said.

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

"Satellites have given us an awesome, continent-wide picture of how Antarctica is changing", said Dr. Pippa Whitehouse, a member of the IMBIE team from Durham University, according to a University of Leeds press release.

And the ice losses quickened to 219 billion tons a year since 2012, from 76 billion previously. "To do this, we need to keep watching the ice sheet closely, but we also need to look back in time and try to understand how the ice sheet responded to past climate change".

Another component of the East Antarctic Ice Sheet, marine-based ice, sits below sea level and is thus directly affected by the ocean.

The unsettling trend is expected to continue. In East Antarctica the picture has been muddled as the ice sheet there gained mass in some years and lost mass in others.

Twila Moon, a research scientist at the National Snow and Ice Data Center, University of Colorado, who was not involved in the study, said the research was further confirmation that Antarctica is losing ice at an "increasingly fast pace". "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. The rate at which ice losses from Antarctica will increase in response to a warming world remains uncertain.

From 1992 to 2012, sea levels were said to be rising at an average of 0.2mm each year due to ice loss.



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