The 2016 floods are huge in scale — virtually all parts of the country have been hit by devastation. And remember, it is not just about some water that enters homes. Floods claim lives, destroy property and crops. In this way, all the years of developmental efforts are lost in one stroke. It is also clear that we worry about floods only when it affects the urban population. Even during the deadly 2013 Uttarakhand floods, the tragedy reached our television screens only because of the large numbers of people who died or were trapped in the swirling waters belonged to urban centres. Floods do not, otherwise, get serious media coverage. We do not know how bad the situation is or how it is getting worse. Floods, then, have become part of the cycle of boredom; they will come every year. So, what is new?
What is new is that each year the intensity and scope of floods are increasing. What is also new is that this year, floods are happening in the time of drought. What is also new is that this year it is evident that floods are not because of “normal” or even “excess rainfall”, but because of extreme and horrific rain events — rain that gushes down from the sky in record time to take over land and property.
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But on the other hand, there is also something new afoot: Extreme rain events. The India Meteorological Department divides extreme rainfall events into two categories — rainfall of 124.5-244.4 mm in 24 hours is “very heavy” and rainfall more than that is “extremely heavy”. In July alone, Assam recorded six “very heavy” rainfall days. In Madhya Pradesh’s Burhanpur and Betul districts, in one day – on July 12 – it rained to ruin completely. This is because rainfall was 1,000-1,200 per cent higher than “normal”. On August 20, Bihar’s 12 districts recorded “very heavy” or extreme rain events. In drought-hit Rajasthan, in just one day – on August 11 – rainfall was 100 per cent above normal. In Pali and Sikar districts of the otherwise dry state, on that day, it rained so much that it broke all records — 1,000 per cent above normal. The list goes on and on.
In each case what this has meant is as follows. One, the same region, in one stroke (literally) has gone from extreme and back-breaking drought to extreme and back-breaking flood. Two, in many cases, even when there is extreme flood in the state, the total rainfall received is below normal. In Assam, even when 90 per cent of the state is under water, the rainfall received was 25 per cent below normal. It is important to understand the “newness” in the growing numbers of “very heavy” rain events. The fact is that scientists have long warned that as the planet warms, not only will it rain more, but this rain will become more variable and more extreme. This is what we are beginning to see more and more.
My colleagues have also studied what scientists understand about the nature of clouds, and this points to yet another worrying discovery. It is possible that the air pollution that is choking us in our cities, is also disrupting the nature of cloud formation and leading to extreme rain events. The interaction between human-made aerosols – tiny organic and inorganic particles – and clouds is changing the nature of the monsoon, say scientists. They find that these microscopic pollutants act as sites where water vapour condenses to form cloud droplets. The greater the number of aerosols, the higher the droplets. But then, as nature’s interactions also show, the result is not linear or simple. This interaction between aerosols and droplets that form clouds could lead to less rain; it could lead to extreme rain and it could lead to lightening that, in turn, kills and maims on the ground. Despite the uncertainties that exist, what is certain is that change is happening; fast and deadly. It is time we took note of this new extreme reality of floods.
sunita@cseindia.org
Twitter: @sunitana