It’s not just the Gangotri glacier that is receding. Actually, thousands of Himalayan glaciers are shrivelling up in varying degrees. The Pindari glacier is receding by 23 metres a year, Bara Shigri by 36 metres a year, Dokriani by 18 metres, Meola by 35 metres, Sonapani by 17 metres, Milam by 13 metres, Zemu by 28 metres — to name just a few.
Cumulatively, this melt could change the way we know our world. If global warming isn’t arrested, rivers will first flood and then dry up; seas will rise and fertile lands will turn barren.
Until recently, such talk seemed the prattle of doomsayers. No longer. The devastating impact of melting snows, rising seas and drying rivers is virtually upon us. Within the lifetime of many of us, the Ganga could be a pale shadow of its current glory; shoreline cities and towns, including Mumbai, could be compelled to build dykes to keep out the invading seas; agricultural yield in the fecund Gangetic plains could become insufficient to feed our billion-plus population. That is, unless we act now.
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Glaciers cover nearly 38,000 sq km of the Himalayan mountains which, in turn, accounts for 800 cubic km of water flow annually. This nurtures the great Indian civilisation as we know it. Rapid melt of this snow mass is expected to cause floods initially. But within two decades — by 2030, to be precise — when glaciers would have significantly melted, the situation is expected to reverse and several rivers will become a mere trickle.
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http://timesofindia.indiatimes.com/Melting_glaciers_Flood_of_troubles/articleshow/2008090.cms