Global warming may not cause downpours in India

Floods may occur in some places but bypass others

No doubt some of the meteorological stations may receive heavy rainfall due to global warming, but their adjacent stations may not, says a new research that studied trends in Indian monsoon for more 1,800 Indian stations over the last 50 years.

On a policy front, the variability in heavy rainfall pattern is a clear indicator that it would be wrong to develop a single strategy for flood management for the entire country. Rather the policies have to be framed at a regional level for better management of flood hazards.

Analysing observed rainfall data from 1803 stations of Indian Meteorological Department with a statistical theory on extreme events, which is also used to identify future trends in telecommunication and finance, an Indo-US team found no uniform increase in heavy rainfall pattern for the entire country and even for an entire region like central or peninsular India.

Rather it could be a mixed-case scenario in which some stations will receive heavy rainfall but others will not.

Contrary to previous studies by other climate researchers, the new study also does not suggest any significant increase in heavy rainfall pattern in the last five decades.

“Heavy rainfall during the last half century has shown no increasing trend in an average sense over all of India. But the growth in spatial variability of rainfall extremes over India in the same period has been fairly large and relatively pervasive. No one has shown this specific result before,” corresponding author Auroop Ganguly from Northeastern University in Massachusetts told Deccan Herald.

The study published in the latest issue of the journal “Nature Climate Change” suggests that besides global warming, local factors like urbanisation, forest cover loss and land use change have to be taken into account in the planning pro­cess.

Since there is a high variability from station to station in rainfall pattern, for an urban planner, it would be wrong to plan for a very wide drainage system for the entire country. Some places might not need it, said co-author Subimal Ghosh at Indian Institute of Technology, Mumbai.

“For about half a decade now, researchers have been publishing contradictory findings about the trends and patterns of heavy rainfall events over India, using the same data that we used but different methods. This was not very helpful for policy,” said Ganguly.

The research echoed the same sentiments as that of a Parliamentary Standing Committee on agriculture, which in its report tabled in Parliament on Monday underscored the need of doing away with “futile and unrealistic planning” in agriculture to counter the impacts of climate change.