Tuesday, May 14, 2013

New paper finds potential sea level rise from Greenland is about 66% less than previously estimated

A new paper published in Nature finds the upper limit to sea level rise by 2100 from the Greenland ice sheet is about 66% less than previously predicted. The paper follows another from last week demonstrating the upper limit of sea level rise by 2100 from the Antarctic ice sheet is about 70% less than IPCC predictions. These new papers demonstrate IPCC predictions of sea level rise from both Greenland and Antarctica have been greatly exaggerated. Furthermore, the new estimates of these upper limits may themselves be exaggerated, since they are based upon models with high sensitivity to CO2, which has also been debunked by several recent papers

Ice loss from Greenland's glaciers may level off
Simulation suggests long-term effect on sea level not as dire as some predictions

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The acceleration of iceberg calving from Greenland’s glaciers could level off by midcentury, researchers predict. Shown is the edge of Kangiata Nunata Sermia where the glacier meets the ocean.
Dirk van As
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The increasing pace of ice breaking off Greenland’s glaciers and dumping into the ocean may not actually be a warning sign of runaway ice loss and catastrophic sea level rise, researchers report in the May 9 Nature.
Greenland’s ice sheet raises sea level when the surface melts or when glaciers flow into the sea and discharge icebergs. Scientists have been concerned that the last decade’s acceleration in iceberg calving would continue unchecked. Simulations have been unable to verify or refute those fears because it’s difficult to account for all of the processes, such as warm seawater’s melting of a glacier’s base, that influence how the streams of ice move and shed icebergs.
Now, Faezeh Nick of the Universit√© Libre de Bruxelles in Belgium and colleagues have incorporated all of these variables into a simulation that predicts the activity of four of Greenland’s main glaciers. In a scenario where global temperatures warm 2.8 degrees Celsius by 2100, the glaciers’ rate of ice loss eventually levels off, the simulation suggests. In total, the four glaciers could raise sea level by about 1 centimeter by 2100.
Applying the findings to the rest of the island’s glaciers, the researchers predict Greenland could add as much as 18.3 centimeters to sea level by the end of the century. That amount is about 35 centimeters less than a previous estimate that extrapolated Greenland’s current ice loss acceleration into the future. 
F.M. Nick et al. Future sea-level rise from Greenland’s main outlet glaciers in a warming climate. Nature. Vol. 497, May 9, 2013, p. 235. doi:10.1038/nature12068.[Go to]
E. Wayman. Shrinking polar ice caused one-fifth of sea level rise. Science News. Vol. 182, December 29, 2012, p. 10. [Go to]
D. Powell. Study keeps pace with Greenland glaciers. Science News. Vol. 181, June 2, 2012, p. 10. [Go to]
A. Witze. Ice in motion. Science News. Vol. 179, March 26, 2011, p. 22. [Go to]

1 comment:

  1. http://environmentalresearchweb.org/cws/article/yournews/53481