Antarctic ice loss increases to 200 billion tonnes a year

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In these five years, Antarctica lost near about two hundred nineteen billion tons of its ice sheet each year.

The findings show that before 2012, Antarctica lost ice at a steady rate of 76 billion tonnes per year - a 0.2mm per year contribution to sea level rise.

Time is rapidly running out to save Antarctica and the rest of the world from the catastrophic runaway effects of climate change, scientists have warned.

IMBIE was established with the support of NASA and the European Space Agency, to monitor the changes in ice-sheet cover around the world.

"Unfortunately, we appear to be on a pathway to substantial ice-sheet loss in the decades ahead, with longer-term consequences for enhanced sea-level rise; something that has been predicted in models for some time". Just two glaciers in this sheet, Thwaites and Pine Island, now contribute about half of Antartica's annual ice mass loss, according to the study's authors.

New insights into the process, led by an global team including the University of Otago's Professor Vernon Squire, have been published today in the major scientific journal Nature.

ESA says that the CryoSat carries a radar altimeter and is created to measure changes in in height of ice, which is then used to calculate changes in ice volume.

To analyze the ice, the researchers use three different kinds of measurements.

Millimeters of sea level rise may not sound like much, but previous surveys suggested that Antarctica's massive ice sheets likely wouldn't be affected by climate change at all.

What's happening in East Antarctica is extremely important because it has by far the most ice to give, being capable of raising sea levels by well over 100 feet. The latter is increasingly being viewed as posing a potential planetary emergency, because of its enormous size and its role as a gateway that could allow the ocean to someday access the entirety of West Antarctica, turning the marine-based ice sheet into a new sea.

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.

The ice sheet mass balance inter-comparison exercise (IMBIE) is an worldwide effort: a team of 84 polar scientists from 44 organisations, including both of us, working together to provide a single, global record of ice loss from Earth's polar ice sheets.

At the northern tip of the continent, ice shelf collapse at the Antarctic Peninsula has driven a 25 billion-ton increase in ice loss since the early 2000s.

As atmospheric temperatures are expected to rise in the coming decades and centuries, more surface meltwater will be available on fractured ice shelves, which could result in many more catastrophic ice loss events, according to the study. The increases are on the order of a few millimetres per year, but scientists need to account for them to ensure their other measures of ice loss are accurate.

The Atlantic noted this week that millions of people on the U.S. East Coast could be displaced from their homes by the end of the century because of melting in parts of western Antarctica ― which scientists have identified as being the source of most of the recent melting.

Almost all of the mass shed over the last quarter century has come from West Antarctica, the study found.

Greenland's dwindling ice sheet, as well as melting mountain glaciers elsewhere and the fact that warmer water expands, are also contributing to rising seas.

"If we aren't already alert to the dangers posed by climate change, this should be an enormous wake-up call", said Martin Siegert, of the Grantham Institute at Imperial College London, and one of the authors. The total contribution is highlighted by the bold white line, while the blue lines track the individual contributions from East Antarctic, the Antarctic Peninsula and West Antarctica.