Racing to Find Answers in the Ice - The New York Times

Scientists are racing to understand what is happening to the Ross Ice Shelf — and the rest of Antarctica — as the planet warms around it.  They are trying to map the thickness of the ice and the shape of the sea floor beneath it in an effort to gauge how vulnerable the shelf may be to collapse, and how soon that could happen.

Scientists are also trying to measure the role of human-caused climate change in weakening some parts of the West Antarctic ice sheet, and to fathom how damaging the seas around the continent might prove to be as they warm over time. 
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Unraveling the answers, and gaining a better understanding of how Antarctica’s ice has waxed and waned in the past, may offer a rough guide to the changes that human-caused global warming could wreak in the future.

Already, scientists know enough to be concerned.  About 120,000 years ago, before the last ice age, the planet went through a natural warm period, with temperatures similar to those expected in coming decades.

The sea level was 20 to 30 feet higher than it is today, implying that the ice sheets in both Greenland and Antarctica must have partly disintegrated, a warning of what could occur in the relatively near future if the heating of the planet continues unchecked.

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The most vulnerable parts of the West Antarctic ice sheet could raise the sea level by 10 to 15 feet, inundating many of the world’s coastal cities, though most scientists think that would take well over a century, or perhaps longer.  They are worried about a possible rise of as much as six feet by the end of this century.

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