While popular opinion states that Western Ghats are a source of capturing rainfall and water resources, a series of studies conducted by the Indian Institute of Science (IISc) has shown that rainfall in some parts of the Ghat regions has reduced, adverse affecting sources of water supply water to cities.”
The study titled ‘Monsoon circulation interaction with Western Ghats Orography under changing climate,’ was published in 2012. Subsequently, a team of researchers from IISc also published a series of papers in the last two years supporting this publication and proving that rainfall had reduced over the years. They did so by using high resolution models to study the rainfall patterns and cloud covers.
These papers have also been shared with the Kerala government, but are yet to be submitted to the Karnataka government. Prof K Rajendran, principal scientist and associate professor of the Academy of Council of Scientific and Industrial Research (ACSIR), was one of the research professors who conducted the study. “There is a 20 to 25 percent reduction in rainfall over the years. This is hampering groundwater table and water bodies, which bring water to prime cities including Bangalore, Mangalore and a few others abutting the Ghats,” he said.
“In the study, we have explained that this is effect is not just because of global warming. It is also because of changing land use, urbanisation, reduction in moisture content in the wind, increasing heat in the upper atmosphere, changing circulation in wind pattern, deforestation, change in livelihood, atmospheric pollution and urban heating,” he added.
Rajendran also said that this has been gradually happening since the last decade and will continue to occur for another 10 years. “There could also be variations in the rainfall pattern. At present, the rainfall has reduced by 2 mm this monsoon. The next monsoon could see either a reduction or an increase by one millimetre. This is crucial because the groundwater table builds over the years and now, depleting rainfall will hamper it.”