Ice Reserves in the North and South Poles
In comparison with the ice stored in glaciers in other parts of the world, the concentration in Antarctica and Greenland is enormous – 15,312,710 square kilometers (5,912,243 square miles) out of a global total of 15.861,766 square kilometers (6,124,234 square miles) – that is, almost 97%. And even this understates the comparison since the mountain glaciers are relatively thin while the ice sheets in the polar areas range up to 3 kilometers (2.4 miles) deep. Antarctica holds enough ice to raise sea levels by about 57 meters (187 feet) and Greenland contains enough ice to raise sea levels by about 7 meters. The potential for change is enormous, and even a small percentage melt could be catastrophic. Thus the speed of melting in the polar areas is particularly significant.
NASA scientist Eric Rignot reported on March 10, 2011 that studies performed by his team showed that between 1992 and 2009, ice was melting faster than previous studies had found. The two regions lost on average 36.3 billion tons more ice every year than the previous year; if this trend continues, it could raise oceans 15 centimeters (6 inches) between 2010 and 2050 and 56 centimeters (22 inches) by 2100. Expansion of sea water as temperatures rise would add another 9 centimeters ( 3.5 inches). In addition, Rignot found, melting of glaciers would add 8 cm (3 inches). His figure for glaciers, 8 cm, was judged too low by Frank Paul (Nature Geoscience 4, January 31, 2011). He thought it would be 50% more – 12 cm – by 2100. That would make a grand total – on current estimates – of between 71 centimeters (28 inches) and 75 centimeters (29.53 inches). That is much more than the previous estimate (Fourth Assessment Report, the Intergovernmental Panel on Climate Change, IPCC, in 2007); it projected 18 to 59 centimeters (7.1 to 23.2 inches) .
Studies by other scientists give even higher figures. As Justin Gillis wrote (November 13-14, 2010 International Herald Tribune), Stefan Rahmstorf of the Potsdam Institute for Climate Impact Research in Germany and Tad Pfeffer of the Institute of Arctic and Alpine Research at the University of Colorado, “using different methods, arrived at the guess that sea level could rise between 75 cm and 2m by 2100. Most climate scientists hold that the best estimate is roughly 1m [39 inches].“
In anticipation of the Affordable World Security Conference William R. Polk's series of articles will provide a 'reader friendly' and insightful overview of conditions, developments and activities that are subtly but powerful affecting our daily lives.
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