By Rahul Sachitanand
Vimal Mishra, meteorologist and assistant professor at IITGandhinagar, was part of a recent committee to investigate the floods at Dhanera in Gujarat. Heavy rains had lashed Gujarat and Rajasthan in July, and the normally quiet Rel river had overflown, causing havoc in the neighbouring areas.
As part of a team investigating the impact of this flooding, Mishra looked at the statistics of rainfall and river flows, and compared them with historical figures. In two days, the region had got twice the seasonal total of rainfall, the water level in the river had exceeded 50 times the high water mark. “I was shocked by the numbers,” says Mishra.
In his own research, Mishra along with his colleagues was investigating the correlation between extreme meteorological events and climate change. Four years ago, he found that the maximum rainfall was not showing an increase over the last century except in four of 57 towns and cities.
In his later work, he showed that extremes are expected to increase over the current century. Specifically, he found that one-to-five-day extreme rains, at levels found once in about 500 years, can increase by about 20-30% over the next century if global warming goes unchecked.
If Dhanera in Gujarat set new benchmarks for precipitation, then the role of climate change can’t be ignored in the downpour that drowned Mumbai on August 30. If much of the disaster can be blamed on an inadequate drainage system, sustained changes in weather patterns may have only made it worse. In 24 hours, India’s commercial capital was deluged by 331.4 mm of rain, which claimed lives, flooded roads and swamped railways. As the effects of climate change set in, this may become more commonplace in Mumbai and beyond.
Kristie Ebi, Professor of Global Health and Director of the UW Center for Health and the Global Environment, is the co-author of a report referenced in the article.