March 2, 2009
South Asian monsoons may become weaker
A U.S.-led study warns the South Asian summer monsoon season, critical to agriculture in Bangladesh, India, Nepal and Pakistan, might become weaker.
Experts at the Purdue University Climate Change Research Center say climate change could influence monsoon dynamics and cause less summer precipitation, a delay in the start of monsoon season and longer breaks between the rainy periods.
Associate Professor Noah Diffenbaugh, whose research group led the study, said the summer monsoon affects water resources, agriculture, economics, ecosystems and human health across 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.
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.
Monsoons produce approximately 75 percent of the annual rainfall in major parts of the region and nearly 90 percent of India's water supply.
The research that included Purdue graduate student Moetasim Ashfaq, lead author of the study; Assistant Professor Wen-wen Tung; and Associate professor Robert Trapp; Ying Shi and Xueijie Gao of the National Climate Centre in Beijing; and Jeremy Pal of Loyola Marymount University appeared in the Jan. 3 issue of the journal Geophysical Research Letters.