The torrential downpour in Chennai, that received on a single day twice the rainfall for a month, is no doubt a wake-up call for India’s policymakers to deal with climate change on a war footing. Such extreme events are occurring with greater frequency: Hyderabad (2000), Mumbai (2005), Leh (2010), Uttarakhand (2013) and Srinagar (2014), to name a few instances. Although policymakers are aware of the linkage with global warming, they prefer instead to emphasise on the interaction of some disturbance or the other with the monsoon! Metropolitan India, for its part, is woefully unprepared for such unusual events as it lacks flood-proof infrastructure.
It takes only a drizzle to bring the nation’s capital to its knees. As the storm water drains are rarely desilted in time, rainwater floods the roads, creating endless traffic jams. Elsewhere, the runaway pace of urbanisation has resulted in a frenetic pace of house and road building encroaching upon lakes, ponds and wetlands. This happened in Srinagar over 100 years. Over 300 water bodies have disappeared due to illegal construction in the city and suburbs in Chennai. When the rainfall is incessant and reservoirs overflow, where will the discharged water go? For such reasons, an extreme weather event in Delhi is a disaster waiting to happen.
The likelihood of extreme weather events goes up with rising global average surface temperatures or global warming. The impact of this latter phenomenon has already been felt in Indian agriculture, for instance. Higher temperatures due to global warming during the key months of January-February has drastically affected the rabi or winter crop yields of wheat in the vanguard surplus-producing states of Punjab, Haryana and western Uttar Pradesh. The gradual retreat of Himalayan glaciers, that feed most of India’s rivers, is also believed to adversely impact the availability of water for food production.
But a bigger problem is the unpredictable nature of the southwest monsoon for agricultural production. More than half of India’s workforce lives off the land and eagerly awaits the monsoon-bearing nimbus clouds cross Kerala’s coast every June; sweeping over the peninsula and carpeting the rest of the country with rainfall till September. Although this highly complex, dynamic system arrives with unfailing regularity, there is no telling exactly when it would set in, or for that matter, its behaviour over the season. Predicting its spatial and temporal spread has been a daunting challenge even with sophisticated weather models.
Against the backdrop of climate change, scientists from the Bengaluru-based Centre for Mathematical Modelling and Computer Simulation investigated whether the monsoon is also changing in terms of duration or spatial coverage on the basis of daily rainfall data for the period 1951–2003. What ought to make policymakers take serious note is their findings – published in the Geophysical Research Letters – of decreasing trends in the quantum of both pre and post-monsoon rainfall and number of rainy days – which clearly imply a shorter monsoon. But there is no significant decline in rainfall during the monsoon season.
What is disturbing is the observed sharp decrease in the area that receives a certain amount of rainfall in the country. If there is as much as a 30 per cent reduction in the spatial coverage of the monsoon, the upshot is that such regions soon become unviable for cultivating certain crops. The reality of climate change thus has important implications for the sustainability of agriculture in the affected regions. In 2015, deficient and scanty rainfall or what is known as drought conditions affected half the number of districts in the country that had 660 million people.
Scarce rains hold out the prospect of distress, especially for small farmers and labourers subsisting on rain-fed agriculture, which characterises vast parts of peninsular India. There is already a serious agrarian crisis, a narrative that has a lot to do with the spread, depth and intensity of drought conditions. On the other hand, plentiful rainfall presages higher food production during the kharif or summer season (sown in June-July). Higher rural incomes generate demand for consumer goods and tractors that translate into higher industrial and GDP growth. Good rains reinforce the growth momentum of the Indian economy.
Clearly, India needs to prepare for extreme weather events. A study of the Indian Institute of Tropical Meteorology, Pune, observed that between 1950 and 2000, the incidence of heavy rainfall events (more than 100 mm/day) and very heavy events (more than 150 mm/day) have increased and moderate events (5-100 mm/day) have decreased. In other words, the prospect is for the country to get heavier rainfall during a lesser number of rainy days as the duration of the southwest monsoon has shrunk over time. The increasing frequency of heavy rainfall events flooding Mumbai, Hyderabad and Chennai corroborate this pattern.
If this is what extreme rainfall can do to Chennai, imagine the damage that can be inflicted with cyclones in the Arabian Sea and the Bay of Bengal. Writing in a leading newspaper, Professor Adam Sobel of Columbia University, argued that a major storm surge in Mumbai would inflict a damage that is much worse than the 2005 floods as it affects low-lying coastal areas, including much of the city’s most valuable real estate, as well as large vulnerable populations in poorer areas. That it could come on violently on the western shoreline. The frequency of cyclone formation has increased in the Arabian Sea even as it has decreased in the Bay of Bengal.
For such reasons, flood-proof infrastructure is the need of the moment. All this talk of smart cities can wait as urban India needs to upgrade its drainage and rain water harvesting facilities before the monsoon arrives. Gaps in the civic administration need to be plugged. Many of the concerned departments are highly prone to corruption. Tamil Nadu has spent thousands of crores of rupees on storm drainage projects but it has gone down the drain! There is also the need to coordinate relief efforts with social media-friendly private initiatives. No doubt, there is a need for surviving the ravages of climate change.
(N Chandra Mohan is an Economics and Business Commentator based in New Delhi)
