ABSTRACT
South Asia is noted for climate and hydrological extremes such as floods, droughts, heat waves, and cyclones. The climate of South Asia is highly influenced by the Southwest monsoon (see Chapter 1). More than three-quarters of the annual precipitation occurs in the monsoon months (June-September). The onset and departure of the monsoon is spatially highly variable, so the precipitation is also. The failure of the monsoon and high summer temperatures leads to drought in many parts of Bangladesh, India and Pakistan. In the Eastern Coast of India and in the coastal region of Bangladesh disastrous cyclones are regular visitors. Glacier Lake Outburst Floods (GLOFs) in Bhutan, Nepal and Pakistan cause disasters to life and property downstream, resulting in serious death tolls as well as the destruction of valuable forests, farms and costly mountain infrastructure. In Nepal and Bhutan, 44 glacier lakes have been identified as potentially dangerous and which may result in GLOF (ICIMOD, 2001). In South Asia, particularly in the Himalayan region, the frequency of the occurrence of GLOF events increased in the second half of the 20th
century. The 1990s was the warmest decade of the last century and several extreme climate
events occurred in the South Asia region. In July of 1993, the Tistung station in Nepal registered 540 mm rain over a 24-hour period triggering a severe flood. Severe droughts occurred over large regions in India and Pakistan in 2000. Bangladesh experienced the worst flood in recent history in 1998 which engulfed about 70% of the country. It appears that extreme climate events are increasing in frequency and magnitude, causing more deaths, injury, disability and disease, economic and social impacts in the impoverished nations of South Asia (Table 11.1). The Intergovernmental Panel on Climate Change (IPCC) (2001) concluded that there would be likely increases in intense precipitation events, droughts, tropical cyclone peak wind intensities and tropical cyclone mean and peak precipitation intensities in the future due to climate change. Therefore, a dramatic increase in damage is also expected.
