Erratic rain is the new normal, it’s time to act

As floods wreak havoc in western and southern India for the second year in a row, scientists have raised red-flags on the increased frequency of flood in future due to warming climate and mindless urbanisation.

In a new study, researchers at the Indian Institute of Technology, Gandhinagar found that the current trend of intense rainfall spanning over a few days (1-5 days) triggering floods in India would increase significantly in the future with enhancement in the emission of green house gases and consequent warming.

The extreme precipitation has not only put agriculture and infrastructure at risk but also has implications for water resources and reservoir operations.

It is not the first warning from scientists. For close to a decade, several studies concluded that Indian monsoon would be more erratic in future bringing extreme rains on a small patch of area in a short span of time.

“The nature of rain spells has changed. We now receive 15-16 cm rainfall in a span of 12-18 hours. The soil is completely soaked and the water has no place to go causing the flood,” M Rajeevan, secretary, Ministry of Earth Sciences told DH.

Indian Ocean sea surface temperature and accumulation of aerosols in upper atmosphere do contribute to localised heavy rainfall. But an equally crucial component also comes from rapid change in land cover and land use pattern primarily due to completely mindless urbanisation.

“While there are changes in the rainfall pattern, a more immediate cause of flooding is human-made, particularly in the cities. Because of excessive cementing, the water has no place to go,” said Ashwini Ranade, a scientist at the National Institute of Hydrology, Roorkee.

“Small water bodies and marshy lands should never be encroached for agriculture or construction. Unfortunately such misuse of land happens all around. It is the same story in Karnataka, Kerala and Maharashtra,” added Rajeevan.

Same sentiments were echoed by T I Eldho, a professor at Indian Institute of Technology, Bombay, “The authorities must stop constructions by the riverside and prevent spoiling of water bodies,” he said. Last year, Eldho and his colleagues demonstrated how concretisation and loss of forest led to frequent floods in the Nethravathi basin in south Karnataka.

Between April 2016 and July 2019, more than 6,500 Indians died in the flood besides two lakh livestock. Also 39 lakh houses were damaged and 88 lakh ha of crops were lost. Unless authorities pull up their socks and address such deficiencies, the numbers will be on the rise in future since increase in extreme and erratic precipitation is set to be the new normal in India.