The article traces the history of global initiatives on assessing present and projections of climate change (CC), describes the scope/status of current activities and program in hand for mitigation and adaptation in near future. It brings out the extent of adverse impacts of CC on water resources alongwith shortcomings of present investigations.

In this study, a general methodology is presented in order to use the downscaled output from a RCM (Regional Climate Models) directly in a hydrologic model for evaluating the impact of climate change on water resources. The hydrologic model used is the Soil and Water Assessment Tool (SWAT). The study area is a part of the Chaliyar River Basin in Kerala, India.

Hydrological modelling of large river catchments is a challenging task for water resources engineers due to its complexity in collecting and handling of both spatial and non-spatial data such as rainfall, gauge discharges, and topographic parameters.

As far as water goes, climate change changes everything. Past experience of rainfall, snowfall, runoff and streamflow is no longer a reliable guide for the future. We'll all be affected, but especially small farmers and the poor and marginalized, who have the least ability to protect themselves against the depredations of droughts, floods and food shortages.