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Use constraints
Using this graphic and referring to it is encouraged, and please use it in presentations, web pages, newspapers, blogs and reports. For any form of publication, please include the link to this page and give the cartographer/designer credit (in this case Hugo Ahlenius, UNEP/GRID-Arendal)
Source(s)
(corresponding to numbers on rectangles): 1 Rignot and Thomas 2002; 2 Ramillien and others 2006; 3 Velicogna and Wahr 2006; 4 Chen and others 2006; 5 Zwally and others 2005; 6 Wingham and others 2006; 7 Rignot and others 2007
Rignot, E. and Thomas, R. (2002). Mass balance of polar ice sheets. Science, 297(5586), 1502-1506
Ramillien, G., Lombard, A., Cazenave, A., Ivins, E., Remy, F. and Biancale, R. (2006). Interannual variations of the mass balance of the Antarctic and Greenland ice sheets from GRACE. Global and Planetary Change, 53, 198-208
Velicogna, I. and Wahr, J. (2006a). Measurements of time-variable gravity show mass loss in Antarctica. Science, 311(5768), 1754-1756
Chen, J., Wilson, C., Blankenship, D. and Tapley, B. (2006a). Antarctic mass rates from GRACE. Geophysical Research Letters, 33, L11502
Zwally, H.J., Giovinetto, M.B., Li, J., Cornejo, H.G., Beckley, M.A., Brenner, A.C., Saba, J.L. and Yi, D. (2005). Mass changes of the Greenland and Antarctic ice sheets and shelves and contributions to sea-level rise: 1992-2002. Journal of Glaciology, 51(175), 509-527
Wingham, D., Shepherd, A., Muir, A. and Marshall, G. (2006a). Mass balance of the Antarctic ice sheet. Transactions of the Royal Society of London Series A, 364, 1627-1635
Rignot, E., Arthern, R., Bamber, J., van den Broeke, M., Davis, C., Li, Y., van de Berg, W.J. and van Meijgaard, E. (2007). A net source of ocean mass from coastal thinning of Antarctic glaciers. In print
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Uploaded on Tuesday 21 Feb 2012
by GRID-Arendal
Antarctica, showing rates of surface-elevation change derived from satellite radar-altimeter measurements
Year:
2007
Author:
Hugo Ahlenius, UNEP/GRID-Arendal
Description:
The figure shows rates at which the ice-sheet mass was estimated to be changing based on radar-altimeter data (black), mass-budget calculations (red), and satellite gravity measurements (blue). Rectangles depict the time periods of observations (horizontal) and the upper and lower estimates of mass balance (vertical). Measurements by satellite techniques based on gravity indicate mass loss at a rate of 138 ± 73 billion tonnes per year during 2002–2005, mostly from the West Antarctica Ice Sheet. That is equivalent to a rise in global sea level of 0.4 ± 0.2 mm per year, or 10–30% of the global rate measured since the 1950s, and is in good agreement with recent massbudget estimates. However, two interpretations of satellite radar altimetry pointed to a much smaller loss of about 31 billion tonnes of ice per year or a net gain of about 27 billion tonnes per year. The difference between these estimates from totally independent techniques reflects the uncertainties in these difficult measurements; nevertheless, on balance, they indicate a recent shift to a net loss of Antarctic ice and suggest that losses may be accelerating. Similar conclusions result from studies of Antarctic Peninsula glaciers, indicating that they are melting much faster than previously predicted and are probably already contributing significantly to sea-level rise.
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