Antarctic ice loss triples, boosting sea levels

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Of that, 40 percent has occurred in the last five years, dumping 200 billion tonnes (220 billion tons) of ice and raising the ocean half a millimeter every year. However, scientists say it's not enough to replace the amount of ice lost.

Antarctica has lost 219 billion tonnes of ice since 2012, up from the 76 billion that was recorded in previous years.

Scientists have acknowledged that these sad results surpassed their expectations.

"We're watching these reports closely", said Michiel van den Broeke, professor of Polar Meteorology at Utrecht University in the Netherlands, saying they were the guide for defending the Dutch coast.

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

A February study in the Proceedings of the National Academy of Sciences based on satellite altimeter data that sea level rise at 3 millimeters per year has accelerated at a rate of 0.084 millimeters since 1993.

While the sediment was the product of erosion from the continent, the low levels of tell-tale chemical signatures reveal that the sediment experienced only minimal exposure to cosmic radiation, leading the team to conclude East Antarctica must have remained covered in ice.

This chart shows the contribution to global sea levels due to changes in the mass balance of the Antarctic ice sheet between 1992 and 2017.

For the new study, the scientists combined data from three types of satellite measurements to track changes in ice over time, study co-author Andrew Shepherd, a professor of Earth observation with the School of Earth and Environment at the University of Leeds in the United Kingdom, told Live Science.

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"They're melting the ice at rates that far exceed anything that would change in the air, and these are forces that you can't reverse easily".

Covering twice the area of the continental United States, Antarctica is blanketed by enough ice pack to lift global oceans by almost 60 metres (210 feet). The findings helped confirm that the Greenland Ice Sheet is a sensitive responder to global climate change.

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. If the rate does not increase, that would imply that sea level would rise by an average of 10 inches by 2100. "According to our analysis, there has been a steep increase in ice losses from Antarctica during the past decade, and the continent is causing sea levels to rise faster today than at any time in the past 25 years", Andrew Shephard, lead author of the study and a professor at the University of Leeds, said in a statement. The rate of sea-level rise due to Antarctic ice loss has tripled since 2012, he said. "This does not mean that at current atmospheric carbon dioxide levels, Antarctica won't contribute to sea level rise".

There have been many other estimates of how much ice has melted in Antarctica.

"The fate of Antarctica, the fate of Greenland, is the fate of Miami", she said.

NOAARapidly rising sea levels that inundate the coastlines where billions of people live is one of the more worrisome concerns associated with climate change.

"The kinds of changes that we see today, if they were not to increase much more. then maybe we're talking about something that is manageable for coastal stakeholders, " said DeConto.

There are "many, many communities where sea level at high tide is really reaching the brim and spilling into the streets more often that it did just decades ago", he said.

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