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West Antarctica glaciers' melting 'have passed the point of no return', says NASA study

Wednesday, May 14th 2014 - 00:15 UTC
Full article 20 comments
“This sector will be a major contributor to sea level rise in the decades and centuries to come,” said glaciologist Rignot “This sector will be a major contributor to sea level rise in the decades and centuries to come,” said glaciologist Rignot
The study presents multiple lines of evidence, incorporating 40 years of observations of glaciers in the Amundsen Sea The study presents multiple lines of evidence, incorporating 40 years of observations of glaciers in the Amundsen Sea

A new study by researchers at NASA and the University of California, Irvine, finds a rapidly melting section of the West Antarctic Ice Sheet appears to be in an irreversible state of decline, with nothing to stop the glaciers in this area from melting into the sea.

 The study presents multiple lines of evidence, incorporating 40 years of observations that indicate the glaciers in the Amundsen Sea sector of West Antarctica “have passed the point of no return,” according to glaciologist and lead author Eric Rignot, of UC Irvine and NASA's Jet Propulsion Laboratory (JPL) in Pasadena, California. The new study has been accepted for publication in the journal Geophysical Research Letters.

These glaciers already contribute significantly to sea level rise, releasing almost as much ice into the ocean annually as the entire Greenland Ice Sheet. They contain enough ice to raise global sea level by 4 feet (1.2 meters) and are melting faster than most scientists had expected. Rignot said these findings will require an upward revision to current predictions of sea level rise.

“This sector will be a major contributor to sea level rise in the decades and centuries to come,” Rignot said. “A conservative estimate is it could take several centuries for all of the ice to flow into the sea.”

Three major lines of evidence point to the glaciers' eventual demise: the changes in their flow speeds, how much of each glacier floats on seawater, and the slope of the terrain they are flowing over and its depth below sea level. In a paper in April, Rignot’s research group discussed the steadily increasing flow speeds of these glaciers over the past 40 years. This new study examines the other two lines of evidence.

The glaciers flow out from land to the ocean, with their leading edges afloat on the seawater. The point on a glacier where it first loses contact with land is called the grounding line. Nearly all glacier melt occurs on the underside of the glacier beyond the grounding line, on the section floating on seawater.

Just as a grounded boat can float again on shallow water if it is made lighter, a glacier can float over an area where it used to be grounded if it becomes lighter, which it does by melting or by the thinning effects of the glacier stretching out.

The Antarctic glaciers studied by Rignot's group have thinned so much they are now floating above places where they used to sit solidly on land, which means their grounding lines are retreating inland.

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  • Chicureo

    Yes, yes and yes... Oh by the way: olive oil, fatty fish and eggs will kill you... Along with red wine and consumption of salt and bacon. Oh my gosh, did they tell you also about cow generated methane causing global warming?
    What idiots!

    May 14th, 2014 - 05:23 am 0
  • zathras

    Oh my, olive oil and fatty fish are actually very good for you. Eggs in moderation are important for diet. Alcohol again in moderation is fine, maybe even a little beneficial. However Salt,oh and we are referring to the Sodium ions here, should be at moderate to low levels. Moderate amounts of Potassium ions found in for instance bananas are really good for you. Bacon tends to be very salty and too much red meat contributes to heart disease. Yes it is surprising but given the large numbers of cows in the world they do contribute to global warming. Greenhouse gasses are those that absorb/emit radiation in the infrared but not the visible wavelengths. Most significantly H2O, CO2 CH4, N2O, O3 and various CFC's. Although the is much less CH4 in the atmosphere then the CO2 CH4 is more than 30 times more “warming”. The other significant source of CH4 is wetlands including rice fields. Even Termites contribute, but at a much lower level.

    May 14th, 2014 - 07:48 am 0
  • Mr Ed

    A few grams of sodium is likely to be fatal if swallowed, well, if it is in the metallic, elemental form.

    Note the stringing together of many ifs, buts, expectations but no science whatsoever, not even an extrapolation. No mechanisms are explained or even alleged, whereas science always has a mechanism that can be tested and rejected or accepted.

    Has anyone noticed that in Antarctica it is as cold as Dante's frozen Hell? Has anyone actually said 'It will all melt into the sea”, no, as they are not saying that, but hoping that people believe something like it.

    May 14th, 2014 - 08:49 am 0
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