Deforestation affects rainfall
CONVERSION OF forests into agricultural lands is weakening India's southwest monsoon, a study published by the journal Nature says. Trees channel moisture from the soil into the air through transpiration. This contributes to around 25 per cent of total monsoon precipitation during the monsoon's later stages. Deforestation, however, replaces deeprooted plants with shallow-rooted vegetation that cannot do the same job. The authors compared two time periods in two Indian regions to analyse the impact of land use and land cover on change in rainfall. Between the 1980s and 2000s, land cover in Central India changed from woody savannah to crop land and from woody savannah to evergreen broadleaf in the Northeast. When the precipitation received in the 1980s and 2000s in the two regions was simulated, a decrease in rainfall was found. The study, conducted by scientists from IIT Bombay and the University of Nebraska, is significant as the southwest monsoon contributes up to 80 per cent of the annual rainfall in the country.