Australia: The Land Where Time Began |
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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.
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Author: M.H.Monroe Email: admin@austhrutime.com Sources & Further reading |