Climate Change

Climate change is real: Strong cyclones to reduce in Bay of Bengal, rise in Arabian Sea by 2050, says study

Globally, the risk of strong tropical cyclones is expected to become more than double by 2050, according to the study

By Rohini Krishnamurthy
Published: Thursday 28 April 2022
The coastal resort town of Digha on the Bay of Bengal. Photo: iStock_

Climate change will have opposite effects on the frequency of strong tropical cyclones along the western and eastern coasts of India by 2050. The frequency will reduce in the Bay of Bengal, traditionally known for its powerful storms, while it will increase in the Arabian Sea, a calmer body of water in this regard, a new study has said.

Experts categorise cyclone severity based on wind speeds, with Category 1 being the weakest and Category 5 the strongest.

Some 2.1 to 3.1 per cent of the total number of tropical cyclones expected to strike in the near future, could be strong. This is a decrease from 5.7 per cent between 1980 and 2017, the study published in Science Advances estimated.

Tropical storms that initially formed more towards the open waters of the Bay of Bengal are likely to form in regions that lie relatively closer to the Indian and Sri Lankan coasts due to climate change, the study predicted.

Read: Is the Arabian Sea no longer pacific?

This shift is likely to cause the cyclones to make landfall sooner, shortening the time needed to intensify into Category 3 or Category 4 tropical cyclones, Bloemendaal said.

In states like Tamil Nadu and Andhra Pradesh, for instance, cyclones can be weaker compared to the 1980-2017 climate conditions, as they had less time to intensify to higher intensities, the expert added.

The Arabian Sea, on the other hand, is likely to see the opposite impact. “Our study predicts slight increases in probabilities of intense tropical cyclones near, for instance, Mumbai and Muscat,” Nadia Bloemendaal from the Institute for Environmental Studies, Vrije Universiteit Amsterdam, who led the study, told Down To Earth.

Bloemendaal and her colleagues arrived at these findings after mapping possible tropical cyclone activity from 2015 to 2050 under the high emissions scenario. The team also estimated wind speed changes in the future.

An increase in Arabian Sea tropical cyclone activity is not unusual. A 2021 study noted a 52 per cent increase in the frequency of cyclonic storms on the west coast. 

Global changes

Globally, the risk of strong tropical cyclones is expected to become more than double by 2050. The Gulf of Mexico is not likely to see the same trend, according to the analysis.

Hong Kong and the South Pacific showed the largest increase in the probability of high-intensity storms.  Maximum wind speeds could go up by around 20 per cent, according to the analysis.

Further, countries that rarely witness tropical cyclones — Cambodia, Laos, Mozambique and many Pacific Island Nations, such as the Solomon Islands and Tonga — might see an uptick in the frequency of strong events, the researchers warned.

“Of particular concern is that the results of our study highlight that some regions that don’t currently experience tropical cyclones are likely to in the near future with climate change,” Ivan Haigh, associate professor at the University of Southampton in the UK, said.

Weaker tropical cyclones and tropical storms, however, are likely to become less common in most parts of the world, the researchers predicted.

On, average, roughly 80-100 tropical cyclones form globally, most of which never make landfall. Over the past 50 years, tropical cyclones have killed 779,324 people and caused $1, 407.6 billion in economic losses, the World Meteorological Organization estimated.

This study identifies ‘hotspot regions’ or places that face a high tropical cyclone risk in the near future, Bloemendaal said.

These predictions could help map the changing flood risk in tropical cyclone regions, the researchers highlighted.

Additionally, it could also help governments and organisations take stock of risks, and ramp up mitigation strategies to minimise loss of life and economic damages, the study recommended.

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