India braces for a second cyclone in a month as it braces for Cyclone Yaas in the Bay of Bengal, which will likely cross the Odisha-Bengal coast on May 26. True, cyclones in the Bay of Bengal are an almost annual affair.
But Cyclone Tauktae in the Arabian Sea, which affected nearly every state on India’s west coast earlier this month, was a rarer occurrence. Not only are cyclones relatively rare in the Arabian Sea, but Tauktae has also intensified (measured by the storm’s surface wind speed) rapidly to become one of the most severe cyclones in the Arabian Sea. Oman in more than two decades. 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.
2011-2020 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.
Also look | Cyclone Yaas intensifies into a “very severe cyclonic storm”; accelerated preparation
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 an increase in the intensity of cyclones, if not the number, than the Bay of Bengal in the future.
âSea surface temperatures over the Arabian Sea have increased, as have the heat content of the oceans. 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. This is because the warming of the Arabian Sea is higher than that of the Bay of Bengal. We must be ready, âsaid 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 don’t just increase cyclones; they also make them more unpredictable
It is essential to predict the trajectories of cyclones to minimize their damage. âClimate 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, âsaid Matthew Roxy 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. If oceanic and atmospheric conditions such as high sea surface temperature and atmospheric instability continue to be favorable, the cyclone will continue to intensify.
âExtremely 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. This leaves us less time to prepare. State-of-the-art cyclone models are unable to select this rapid intensification because they do not accurately integrate ocean dynamics, âKoll ââadded.
The following map shows how 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. turns into an extremely severe cyclonic storm. âTauktae 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, âsaid Mr. Mohapatra, Director General of IMD on May 17.
The west coast has more to lose from cyclones in material terms
The states on the west coast of India – from Gujarat to Kerala – contributed 35% to the country’s GDP in 2018-2019, the latest year for which data for all states is available in the country’s database. Center for Monitoring Indian Economy (CMIE). States on the east coast – from West Bengal to Tamil Nadu – contributed 21%.
Natural disasters do not affect all sectors of the economy in the same way. An oil refinery has a lot more to lose than a law firm or IT outsourcing company if a city is hit by a cyclone. 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. That number was only 22% for the east coast states.
Of course, it could be said that cyclonic disturbances should not affect the entire state on the Indian coast. HT analyzed data by district from the Annual Industry Survey (ASI) to account for this point. The ASI is the most important source of recorded statistics on organized manufacturing in India. Because ASI stopped publishing statistics by district after 2009-10, the numbers are a bit dated. But the spatial distribution of manufacturing is unlikely to have changed drastically since then.
Analysis shows that the problem could be worse than it appears. 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 districts. Of these 100 districts, 15 were on the west coast, 12 were on the east coast, and 73 were not on the coast. The production value of the West Coast districts was disproportionately greater than their number. The western coastal districts among these 100 accounted for 27.4% of India’s total manufacturing output, while the eastern coastal districts and non-coastal districts among the 100 accounted for 10% and 44.4%.
Certainly, as the attached map shows, there are also neighborhoods that are not exactly on the coast but are close to it and have a significant share in manufacturing output. Pune, for example, had a share of 3.29% – the fourth highest among 593 enumeration districts – and is close to the coast, but not exactly on it.
The west coast has more densely populated districts, which also poses a greater risk to human lives
It is not just money at stake if cyclones intensify on the west coast. The west coast has more densely populated pockets than the east 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 ââpeople 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 evacuation and rescue operations more difficult as cyclones intensify in the future.
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