Australia: The Land Where Time Began

A biography of the Australian continent 

Antarctic and Greenland Ice Sheets - Acceleration of their Contribution to Sea Level Rise

According to the authors1 there has recently been a substantial improvement in the estimates of mass balance of ice sheets by a number of methods, over different periods of time and various levels of spatial detail. A number of factors, such as the inherent uncertainties of the various techniques, a lack of detailed comparison between independent estimates, and the effect on the surface mass balance of ice sheets of temporal modulations. In this paper the authors1 say they have presented a consistent record of the mass balance of the Greenland and Antarctic ice sheets for the past 20 years, that have been validated by comparison with 2 independent techniques for the past 8 years. These techniques are one differencing perimeter loss from net accumulation and one using a dense time series of time-variable gravity. They found the agreement between the 2 techniques of mass loss to be excellent. A combined mass loss of 475 ± 158 Gt/yr, which is equivalent to a sea level rise of 1.3 ± 0.4 mm/yr. They note that over the last 18 years the acceleration of loss from ice sheets was 21.9 ± 1 Gt/yr2  for Greenland and 14.5 ± 2 Gt/yr2 for Antarctica, which gives a combined total of 36.3 ± 2 Gt/yr2. The authors1 say the acceleration is 3 times larger than that of mountain glaciers and ice caps (12 ±  6 Gt/yr). If this trend continues they suggest the dominant contributor to sea level rise will be ice sheets in the 21st century.

Sources & Further reading

  1. Rignot, E., I. Velicogna, M. R. van den Broeke, A. Monaghan, and J. Lenaerts. "Acceleration of the Contribution of the Greenland and Antarctic Ice Sheets to Sea Level Rise." Geophys. Res. Lett. 38, no. 5 (2011): L05503.
Author: M. H. Monroe
Last updated 03/08/2013
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