Antarctica Is Melting Three Times Faster Than a Decade Ago

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Sea level rise is a threat to cities from NY to Shanghai as well as low-lying nations from the Pacific Ocean to the Netherlands.

It's "possible that Antarctica alone can add about half a foot to sea level rise by the end of the century", Shepherd said in an interview with The Associated Press. They concluded that some ice on the southernmost part of the continent could be stable in a warming climate, as was the case during the Pliocene Epoch. 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.

"If you take a look at the first IPCC [Intergovernmental Panel on Climate Change] assessment report - 30 years ago, before we had satellite measurements of the polar regions - you'll see that the ice sheets were not expected to respond to climate change at all". NSF funded the USA participation in ANDRILL.

The pace of change can be seen in how much more ice we're losing now than in the past.

The geological history of the massive ice sheet - frozen both above and, in many places, below the ocean's surface - has been hard to pinpoint. "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".

This study focused on the portion of the ice sheet that sits above the ocean. "Data from these missions will help scientists connect the environmental drivers of change with the mechanisms of ice loss to improve our projections of sea level rise in the coming decades", NASA's Tom Wagner said in a statement.

Another component of the East Antarctic Ice Sheet, marine-based ice, sits below sea level and is thus directly affected by the ocean.

The study, published Wednesday in the journal Nature, has been described as the most exhaustive analysis ever conducted on the changes to Antarctica's ice sheet.

Rising sea levels pose a major threat to ecosystems, coastal areas and climate as a whole. "A tripling every decade, were it to continue, would reach that volume of sea level rise even sooner".

"We have already spent more than two-thirds of that carbon budget".

Shakun's co-authors on the paper include Carling C. Hay, also of Boston College; researchers Lee B. Corbett, Paul R. Bierman, Kristen Underwood and Donna M. Rizzo of the University of Vermont; Susan R. Zimmerman of the Lawrence Livermore National Laboratory; Marc W. Caffee of Purdue University; and Tim Naish and Nicholas R. Golledge of Victoria University of Wellington, New Zealand.

From 1992 to 2011, Antarctica lost almost 84 billion tons of ice a year (76 billion metric tons). This has led to an increase in sea levels of roughly three-tenths of an inch, which doesn't seem like much.

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

The researchers analyzed sediment contained in drill cores taken from the sea floor.

Finally, the scientists are recording gravity measurements for Antarctica. "This study shows that we're actually losing more mass along the edges of the ice sheet, where the ice sheet is making contact with the ocean, and that the warming oceans are melting the ice", Koppes said.

In the Greenland study, levels of beryllium-10 found in sandy deposits brought out to sea in icebergs suggested the ice sheet has been a "persistent and dynamic" presence that melted and re-formed periodically in response to temperature fluctuations.

Antarctica is one of the world's fastest-warming regions. But it was unclear whether terrestrial ice also retreated. 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.

So far scientists are not comfortable saying the trend in East Antarctica will continue.

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