India experienced its second cyclone in a month as Cyclone Yaas in the Bay of Bengal hit Odisha and the West Bengal coast on May 26. True, cyclones in the Bay of Bengal are almost annual.
But Cyclone Tauktae in the Arabian Sea, which hit nearly every west coast state earlier this month, was a rarer occurrence. Not only are cyclones relatively rare in the Arabian Sea, but Tauktae has also intensified rapidly. This is something the Indian Meteorological Department (IMD) did not anticipate. With the climate crisis, the Arabian Sea could see more intense cyclonic disturbances in the future, experts say. HT analysis shows this will come at a much higher cost in lives and livelihoods than hurricane activity on India’s east coast.
The 2011-2020 period saw the highest number of cyclones in the Arabian Sea since the 1890s
IMD has records of cyclones between the two main seas of the northern Indian Ocean – the Indian Ocean region north of the equator – dating back to the 1890s. Analysis of the data by decade shows that the Bay of Bengal has experienced more cyclones than the Arabian Sea in each decade since 1891-1900. However, the data also shows that the Arabian Sea is increasingly turbulent. It experienced 17 hurricane events between 2011 and 2020, the highest in a decade since the 1890s. Eleven of them were severe hurricanes. Climatologists, including those at IMD, also suggest that the Arabian Sea may experience a greater increase in cyclone intensity, if not number, than the Bay of Bengal in the future. “The sea surface temperatures over the Arabian Sea have increased, as has the heat content of the ocean. This may not affect the total number of cyclones developing over the Arabian Sea. But when cyclones form over the Arabian Sea, they are likely to experience significant intensification. Indeed, the warming of the Arabian Sea is higher than that of the Bay of Bengal. We must be ready, ”said M Rajeevan, secretary of the Ministry of Earth Sciences. Obviously, stronger cyclones pose a greater threat to life and property in the future.
Warmer oceans not only increase cyclones, they also make them more unpredictable
It is essential to predict the trajectories of cyclones to minimize their damage. “Climate projections indicate that the Arabian Sea will continue to warm due to increased carbon emissions, which will lead to more intense cyclones in the future. Warming oceans have also created new challenges. Cyclones are now intensifying rapidly because the warm waters of the ocean are fueling them, ”said Roxy Matthew Koll, climatologist at the Indian Institute of Tropical Meteorology. A higher sea surface temperature acts as a catalyst for the intensification of low pressure areas into cyclones. “Extremely severe cyclones such as Fani (2019) and Amphan (2020) (in the Bay of Bengal) went from weak to severe in less than 24 hours due to warm ocean conditions. It gives us less time to prepare, ”Koll added. Tauktae intensified from a very severe cyclonic storm to an extremely severe cyclonic storm within hours of 11:30 p.m. on May 16 to 5:30 a.m. on May 17. Its sudden escalation took IMD by surprise. “Tauktae intensified very quickly. We did not say it would escalate into an extremely severe cyclone in our forecast. But this was the case due to extremely favorable oceanic and atmospheric conditions, ”said Mr. Mohapatra, Director General of IMD on 17 May.
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The west coast has more to lose from cyclones in material terms
The states of the west coast of India contributed 35% to the country’s GDP in 2018-2019, the latest year for which data for all states is available in the database of the Center for Monitoring Indian Economy ( CMIE). States on the east coast contributed 21%. Natural disasters do not affect all sectors in the same way. An oil refinery has a lot more to lose than a law firm or an outsourcing-based IT firm. The west coast looks more vulnerable once this is also factored in. West Coast states contributed 46% of India’s manufacturing GVA in 2018-19, while East Coast states contributed 22%. It could be argued that cyclonic disturbances do not necessarily have to affect all coastal states in India. HT analyzed data by district from the Annual Industry Survey (ASI) conducted in 2009-2010 (latest district level data) to account for this. This shows that India’s manufacturing activity is very biased in nature. Of the 593 census districts at the time, 82% of India’s total manufacturing output was concentrated in just 100. Of these, 15 were on the west coast and 12 on the east coast. The production value of the West Coast districts was disproportionately greater than their number. West coast districts among those 100 accounted for 27.4% of India’s total manufacturing output, while east coast districts accounted for 10%.
The west coast is more densely populated, which poses a greater risk to human life
It is not just money at stake if cyclones intensify on the west coast. This coast has more densely populated pockets than the eastern coast. It also increases the risk of loss of human life. There are 33 census districts each on the west (Kutch to Thiruvananthapuram) and east (Kanyakumari to North 24 Parganas) coast of India. While the overall population density of the west coast (474 people per square kilometer) is lower than that of the east coast (565), the average and median density of the districts of the west coast is higher. This means that the west coast has more pockets of high population density than the east coast. This will make the evacuation and rescue work more difficult.
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