The study described below is just about the monsoons -- the potential for melting Himalayan glaciers to drastically reduce the flow in India's rivers is a whole separate disaster waiting to happen.
http://www.chinapost.com.tw/life/environment/2009/03/02/198367/Global-warming.htmGlobal warming could delay the start of the summer monsoon by five to 15 days within the next century and significantly reduce rainfall in much of South Asia, a recent study has found.
Rising global temperatures will likely lead to an eastward shift in monsoon circulation which could result in more rainfall over the Indian Ocean, Myanmar and Bangladesh but less over Pakistan, India and Nepal, the study found.
It could also result in longer delays between rainy seasons and intensify the risk of deadly floods by leading to a significant increase in average rainfalls in some coastal areas of western India, Sri Lanka and Myanmar.
That could have a major impact on agriculture, human health and the economies of the region, warned study author Noah Diffenbaugh.
http://www.usatoday.com/weather/climate/globalwarming/2009-02-27-climate-change-asian-monsoon_N.htmNoah Diffenbaugh, whose research group led the study, said the summer monsoon affects water resources, agriculture, economics, ecosystems and human health throughout South Asia.
"Almost half of the world's population lives in areas affected by these monsoons, and even slight deviations from the normal monsoon pattern can have great impact," said Diffenbaugh, an associate professor of earth and atmospheric sciences and interim director of the Purdue Climate Change Research Center.
"Agricultural production, water availability and hydroelectric power generation could be substantially affected by delayed monsoon onset and reduced surface runoff. Alternatively, the model projects increases in precipitation over some areas, including Bangladesh, which could exacerbate seasonal flood risks."