Antarctica's Ice Sheet Is Melting 3 Times Faster Than Before

In West Antarctica the melting ice tripled from 53 billion tonnes in 1992 to 159 billion tonnes in 2017

In West Antarctica the melting ice tripled from 53 billion tonnes in 1992 to 159 billion tonnes in 2017

"We can not count on East Antarctica to be the quiet player, and we start to observe change there in some sectors that have potential and they're vulnerable, " said Velicogna.

But that has changed. Basically, the current rate of melting in Antarctica has boosted the sea level rise by 0.3 millimeters per year since 1992. "And the ice sheet is now losing three times as much ice", Shepherd adds.

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.

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

The study shows that from 1992 through 2011, the continent lost ice at a rate of almost 84 billion tons of ice a year - accounting for a 0.2 mm per year contribution to sea level rise.

"If we aren't already alert to the dangers posed by climate change, this should be an enormous wake-up call", he added.

West Antarctica experienced the most acceleration in ice loss among regions studied during the research period, growing from 53 billion tons a year in the 1990s to 159 billion tons annually in the final five years.

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.

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 ice sheets of Antarctica are home to as much as 90 percent of the world's freshwater supply.

Working among a team of 80 scientists from 14 different countries, Shepherd helped compile data for a groundbreaking climate study known as the Ice Sheet Mass Balance Inter-comparison Exercise (IMBIE). "But remember for the northern hemisphere, for North America, the fact that the location in West Antarctica is where the action is amplifies that rate of sea level rise by up to an about additional 25 percent in a city like Boston or NY".

"Some of the estimates covered different proportions of the ice sheets, some of them covered different time periods, and all of them used different methods and so it became hard for people who are not specialists to try to pick them apart", says Shepherd.

"We depend upon the satellite measurements to not only tell us how the ice sheets respond but also to make these calculations to sea-level contribution", Shepherd said.

To analyze the ice, the researchers use three different kinds of measurements. You can see ice loss in that area over time in the video above.

Finally, the scientists are recording gravity measurements for Antarctica.

"With the number of scientific studies focusing on this region, the technological tools we have at our disposal and data sets spanning several decades, we have an unequivocal picture of what's happening in Antarctica", Eric Rignot, an Earth system science professor at the University of California Irvine who participated in the research, said in a statement. However, the losses in the last five years have tripled over what they were in the first five years of the period.

Shepherd says that actually, their data shows a "a progressive increase in ice loss throughout the whole 25 year time period". However, he says that now the data is tracking a higher scenario, which could mean almost 6 inches of additional sea level rise in the next century.

"The costs for coastal resilience may have just gone up", she said.

The melting is the result of warmer ocean waters undermining glaciers grounded on sea bottoms around Antarctica and increased surface melt from warmer air temperatures.

If all that ice melted, it would be enough to raise the world's sea levels by roughly 200 feet (60.96 metres).

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