National Institute of Hydrology, Roorkee, 247 667.
The two most important hydrological extremes are floods and droughts. These events pose serious hazards to human populations in many parts of the world. India is a flood prone as well as a drought prone country. These water related disasters are caused because of large diversity in climate and topography of the country. The most common issues related to climate change are: accelerated melting of glaciers, sea level rise, submergence of islands/coastal areas and deviant rainfall patterns. Likely impacts include a greater annual variability in the monsoon rainfall, leading to more intense floods and droughts. Thus, climate change in future is expected to have severe implications on river flows in South Asia including India. Global climate change is likely to result in severe droughts and floods in India, with major impacts on human health and food supplies. Developing countries of temperate and tropical Asia already are highly vulnerable to the extreme climate events such as floods, droughts and cyclones. Climate change and variability would exacerbate these vulnerabilities. Annual and seasonal changes in climate would alter the frequency and severity of major droughts. Changing temperature and evaporation rates would alter soil moisture conditions and the amount of runoff from the catchments into reservoirs. There are some evidences of increases in the intensity or frequency of some of these extreme events on regional scales throughout the 20th century. The abnormalities generated due to climate change are likely to trigger shifts in existing biodiversity patterns and demands for totally new set of land uses.
