Antarctica lost an unprecedented amount of ice in the last five years

Mindy Sparks
June 14, 2018

Changes in global sea level, from 1992 to 2017, due to contributions from the Antarctic ice sheet.

Antarctica holds enough ice to increase sea levels 58 meters, the researchers said.

"The increasing mass loss that they're finding is really worrying, particularly looking at the West Antarctic, the area that's changing most rapidly and it's the area that we're most anxious about, because it's below sea level, " said Christine Dow, a glaciologist at the University of Waterloo in Canada who was not involved in the research.

A collective effort by over 80 scientists across the world used satellite data to determine estimates of ice-sheet mass balance between 1992 and 2017, ultimately calculating that global sea level increased by 7.6 mm in the period.

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

Understanding the rate of Antarctica's melting is crucial for these communities. It also means the ice cliffs at the snout of those glaciers are getting taller and more prone to collapse.

Overall between 1992 and 2017, Antarctica's ice sheet lost 3 trillion tons of ice - enough water to cover Texas to a depth of almost 13 feet, scientists calculated. The tally has since jumped to 0.6mm a year. From 2012 to 2017, the melt rate increased to more than 241 billion tons a year (219 billion metric tons).

However, he said that there is growing evidence that projections of Antarctica's influence on sea-level rise may have been underestimated.

Warmer water is mostly causing the melt on our planet's southern-most continent.

Although the general trend was of reduction, there was some increase in ice cover in East Antarctica.

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.

While some of that loss is due to natural processes-the calving of coastal glacials is part of the natural life cycle of Antarctica's ice sheets-the research describes what's happening as "an important indicator of climate change".

Researchers must extrapolate a smaller amount of data over an area the size of the United States, which can make the analysis less precise.

The study is the product of a large group of Antarctic experts who collectively reviewed 24 recent measurements of Antarctic ice loss, reconciling their differences to produce the most definitive figures yet on changes in 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 we find that by combining all of the available measurements we can iron out the problems that individual techniques have".

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.

Antarctic is hardly alone in losing a elephantine amount of ice. These scenarios are more like data-driven conversation starters according to the authors, all who have won the Tinker-Muse Prize for Science and Policy in Antarctica game out what could happen if the world does nothing - or if policy-makers take significant action in the next 10 years to stop the destruction.

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

"Now when we look again, we can see actually that the signal is very different to what we've seen before", Shepherd said.

Advancements in Earth-observing satellites have enabled researchers to better understand the polar regions. And that ice is melting out at a quickening pace, showing that we're quickly driving the climate over the guard rails that have allowed humanity to flourish.

Direct observation from satellites upended that view.

Shepherd says they've seen the most dramatic effects in West Antarctica, where the ice sheet rests on the sea bed.

Other reports by Iphone Fresh

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