The torrential downpour in Chennai—which has received five-and-a-half times more rainfall than normal this November—leading to water-logging and floods in low-lying areas is a wake-up call for India’s policymakers on building capacity to deal with extreme weather events that are going to become increasingly common as a result of climate change. A depression originating in the Bay of Bengal crossed the coast near the capital city of Tamil Nadu on November 11, resulting in heavy rainfall in the city’s suburbs and other districts of the state. Another depression is likely in the Bay of Bengal around November 15. Elsewhere, in Kerala, too, there have been rain-induced landslides in the districts of Kottayam, Idukki and Pathanamthitta since October. In 2018, more than 400 people died when copious rainfall inundated the state.
Such extreme weather events, studies now show, have a definite link with warming, which is largely attributable to anthropogenic reasons. If this is what heavy rainfall can do to Chennai, it isn’t hard to imagine the damage that can be inflicted with cyclones in the Arabian Sea and the Bay of Bengal, typically between October to December. There has been a higher frequency of cyclone formation in the Arabian Sea and the Bay of Bengal linked to rising sea-surface temperatures. They can inflict damage to Chennai (and other coastal cities) that is much worse than the 2015 flooding. In Kerala, the high-intensity rainfall last month was caused by a low pressure area forming in the Arabian Sea interacting over the state with another low pressure in the Bay of Bengal, according to the Indian Meteorological Department in Thiruvananthapuram.
What can be done to minimise the damage from such extreme, cataclysmic rainfall? Like the rest of metropolitan India, Chennai is woefully unprepared for such events as it lacks flood-proof infrastructure. The runaway pace of urbanisation has resulted in a frenetic house- and road-building that has encroached upon lakes, ponds and wetlands. Hundreds of water bodies have disappeared due to illegal construction in the city and its suburbs. All the talk of smart cities can wait as Chennai urgently needs to upgrade its drainage and rainwater-harvesting facilities before the next northeastern monsoon arrives. The many gaps in the civic administration need to be plugged. Successive state governments claim to have spent thousands of crores of rupees on storm drainage projects, but the floods show it has all gone down the drain. There is a need to maintain the rivers (Adyar and Cooum) and canals which can absorb the flood water. Policy makers must learn the proper lessons from the experience of 2015, to ensure the city is not flooded whenever the rains arrive.
In states like Kerala, checking the degradation of the natural ecosystem in the Western Ghats is imperative. This southern state has witnessed a two-fold increase in landslides as 42% of wetlands, forests, tree cover have been degraded around the Western Ghats, affecting the microclimatic topography according to Abinash Mohanty, programme lead at Council on Energy, Environment and Water. The Print quotes Mohanty as saying that these fractured ecosystems are unable to withstand heavy downpour resulting in considerable loss of lives. Kerala must therefore work on a priority basis to protect natural ecosystems and ensure that infrastructure is made climate-proof to withstand extreme weather events. As scientists keep warning, extreme weather will be the new normal as India will experience more episodes of intense rainfall in the future. The dangerous implications of these trends for the population can be minimised by addressing climate change on a war-footing.