Antarctica's ice sheet is melting 3 times faster than before

Media playback is unsupported on your device                  Media caption Andrew Shepherd

Media playback is unsupported on your device Media caption Andrew Shepherd"The study incorporates 24 independent satellite assessments

"Some of the changes Antarctica will face are already irreversible, such as the loss of some ice shelves, but there is a lot we can prevent or reverse", said Martin Siegert, study co-author and professor at the Grantham Institute in London.

Knowing how much ice Antarctica is losing is critical to understanding how climate change will affect humanity both now and in the future, given the fact that the continent contains enough frozen water to raise sea levels by 58 meters.

A single millimeter of global sea level rise is equivalent to 360 billion tons of melted ice, or an imaginary enormous ice cube with sides about 4.35 miles long.

To get around those problems in this study, more than 80 researchers from around the world collected data from about a dozen different satellite measurements dating to the early 1990s. "The good news is that limited climate change can slow the rate of ice loss, and there are many proven actions that can reduce climate change and be implemented immediately".

"According to our analysis, there has been a step 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", Shepherd said. All that water made global oceans rise about three-tenths of an inch (7.6 millimeters).

Even though Antarctica is covered in ice year-round, its ice sheets retreat and advance in annual cycles, a pattern that has persisted for thousands of years.

"The satellite measurements tell us that the ice sheet is much more dynamic than we used to think", he said.

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

New research published in Nature shows that land-based sectors of the East Antarctic Ice Sheet were mostly stable throughout the Pliocene (5.3 to 2.6 million years ago), when carbon dioxide concentrations in the atmosphere were close to what they are today - around 400 parts per million. "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". "Things are happening. They are happening faster than we expected".

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.

So far scientists are not comfortable saying the trend in East Antarctica will continue. "This has to be a concern for the governments we trust to protect our coastal cities and communities".

In the last 25 years, the ice sheet melted enough water to cover the whole of Texas to a depth of four metres.

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.

In the last quarter century, the southern-most continent's ice sheet - a key indicator of climate change - melted into enough water to cover Texas to a depth of almost 13 feet (4 meters), scientists calculated.

The changes will not be steady, in any case, said Knut Christianson, an Antarctic researcher at the University of Washington in Seattle, by email.

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 USA coasts being one prime destination. "So, every incremental increase in sea level rise really has impacts in terms of flooding".

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