Have you ever wonder why India is witnessing tropical cyclones more frequently in regions that typically do not get affected?

Recently, the Cyclone Amphan struck India and Bangladesh in May 2020. It hit regions of West Bengal and moved towards Bhutan. Amphan caused landfall and lashed coastal areas with ferocious wind and rain. Roads in Kolkata were flooded and its 14 million residents were left without electricity. It was the first super cyclonic storm, at which wind speeds are at 180 kph, to have formed in the Bay of Bengal in the 21st century.

Within two weeks’ time, another cyclone struck India. This time it was on the other side of the Indian Peninsula. Cyclone Nisarga dissipated near the western state of Maharashtra. Experts said that when Nisarga was set to hit Mumbai, it would be the first storm from the Arabian sea to make landfall in the city since 1891. It caused damage of $665 million.

To understand this sudden surge in stormy conditions, it would be worth having a look at the climatology behind cyclones.

The Indian peninsula is surrounded by the Indian Ocean. The region of the Indian Ocean that is west of India is called the Arabian Sea. It is situated between the Indian subcontinent and the Arabian Peninsula. Whereas the region east of India is called the Bay of Bengal.

Owing to being surrounded by water on three sides, India is no stranger to high-intensity cyclones. However, over the last decade, the Indian Ocean has become a cyclone hotspot. Indian Express reported that “Cyclones formed in the Bay of Bengal side of the north Indian Ocean are more frequent and stronger than those on the Arabian Sea side.” Although the two water bodies are part of the Indian Ocean, they have different oceanographic differences. The Bay of Bengal is linked with the pacific ocean through a passageway that accelerates the movement of wind system. 

Tropical cyclones form only over warm ocean waters near the equator. As the ocean’s surface heats up due to the sun, warm, moist air rises upwards. It forms clouds. As more and more warm air rises, it creates a cycle of air that forms into giant humid clouds with an area of lower pressure below. This structure eventually grows in height and size. It spreads to create a spinning tropical cyclone.

Global warming has caused water temperatures to rise which increases the water vapour content of the atmosphere. This climate change has affected overall atmospheric parameters that are more conducive for the formation of stormy tropical cyclones that are more intense and frequent. The Arabian Sea which was relatively a calmer sea is witnessing stormy conditions more frequently.

Climate change affects patterns of cyclones occurrences. As evidenced by the recent cyclones, global warming is shifting patterns in the distribution of tropical cyclones.

As temperature records reach new highs each year, the Indian Peninsula is more likely to experience tropical cyclones.