World Oceans Day: Why and how has the risk of hurricanes increased in the Arabian Sea?

 Nature' last year and 'Taukte' this year. For the second year in a row, the Konkan has been hit by a cyclone before the monsoon. The effects of both these storms have been felt far from the coast.

Considering the North Indian Ocean region, ERVs are usually seen forming hurricanes for the first time in the Bay of Bengal at the end of summer. But this year, the first hurricane of the season has formed in the Arabian Sea.

Not only that, but since 2019, the number of hurricanes rising in the Arabian Sea and their intensity has increased.

But is the Arabian Sea really that turbulent? What should be the reasons for this?

Hurricanes rising in the Arabian Sea

The formation of a hurricane depends on two things. Seawater, especially surface temperature and wind direction.

You can watch this BBC Marathi video to know how cyclones are formed.

But in short, if the temperature at the top of the water rises, it evaporates and moves upwards. So a low pressure belt is formed there. Then the cool air from the surrounding atmosphere begins to flow in a circular direction.

Considering the Indian subcontinent, the Bay of Bengal is shallow in many places. "The Bay of Bengal has a high water surface temperature. It is a hot sea. So there are very strong cyclones," said Dr. Krishna Kumar, head of the Indian Meteorological Department. Mrityunjaya Mahapatra says.

The Arabian Sea is relatively deep, with relatively cold water. As a result, fewer cyclones form in the Arabian Sea than in the Bay of Bengal, and their intensity is lower, experts say.

But in the last three or four years, the picture has changed.

This is the 11th hurricane to hit the Arabian Sea in the last three years. It is also the second most severe cyclonic storm to form in the Arabian Sea in the last three years.

In 2018, three hurricanes, Sagar, Mekanu and Luban, formed in the Arabian Sea. But all three storms turned westward towards Yemen and Oman.

In the year 2019, a record number of storms were set in the Arabian Sea, and in the same season, five cyclones were recorded here namely Vayu, Hikka, Kyaar, Maha, Pawan. Two of the cyclones, Vayu and Maha, moved north to Gujarat-Pakistan.

In early June 2020, a natural cyclone hit the shores of Shrivardhan-Diveagar in Raigad district of Maharashtra. In November, Hurricane Gati hit Somalia.

After nature, cyclone Taukte has washed away the Konkan coast within a year.

Why is the Arabian Sea rough?

These rising hurricanes in the Arabian Sea have also caught the attention of the world. According to experts, the temperature in the Arabian Sea is rising, and that is why the number and intensity of hurricanes are increasing there.

According to a report released by the Indian Meteorological Department in 2019, the surface temperature of the Arabian Sea has increased significantly in the last decade. According to the report, the surface temperature of the Arabian Sea rose by 0.36 degrees Celsius in 2019 compared to 1981-2010.

For the formation of a hurricane, the surface temperature of the ERV sea has to be 27 degrees Celsius. When the hurricane struck, temperatures in the Arabian Sea rose to 32 degrees Celsius, according to meteorological records.

In fact, climate change is likely to change the number and nature of storms around the world, experts say. There is also a paradox here.

The surface temperature of the sea has to be high to form a hurricane. But global warming is causing sea levels to rise. Also, in some places, melting glaciers are mixing with the sea, which is likely to lower the surface temperature. Some scientists believe that this could reduce the number of hurricanes.

For example, as the temperature of the Arabian Sea rises, the surface temperature in the Bay of Bengal may decrease. That is why the intensity of storms may increase in the Arabian Sea instead of the Bay of Bengal.

Researcher H. from Japan. Murakami, M. Sugi and a. In a 2012 research paper, Kitoh said that the frequency of cyclones in the Arabian Sea would increase by 46 per cent, while in the Bay of Bengal it would decrease by 31 per cent.

Abhijeet Ghorpade, editor of Bhavatal magazine and an environmentalist, says, "It would not be appropriate to make a definite prediction of what the picture will be like in the coming three years. But the next step must be taken keeping in mind the changing nature of hurricanes in the Arabian Sea."

Scientists, however, do not seem to be at odds with the increasing intensity of hurricanes.

Mumbai and Konkan threatened?

Even if a cyclone hits the Arabian Sea, it is less likely to hit Mumbai directly.

"Equatorial winds in the Northern Hemisphere blow from east to west, ie from Mumbai to the sea. The resulting cyclone moves further and hits the coast of Gujarat. Even if cyclonic conditions are created in the Arabian Sea, such storms often move away from Mumbai," says Abhijeet Ghorpade.

If you think of any storm in the oceans on earth, this is the picture you see. Although the storm in the Arabian Sea did not hit Mumbai directly, it could cause major damage in Mumbai and the Konkan, as cyclones Fayan in 2009 and Taukte in 2009 have shown.

Researchers also predict that sea levels in Mumbai will rise by 1.8 meters this century due to rising sea levels and global warming. Against this backdrop, even a low-intensity cyclone can cause major damage to the city and the Konkan coast.

Writer and novelist Amitabh Ghosh, who writes extensively on the environment, recalls in an interview with the BBC that "between 1998 and 2001, three cyclones hit the Indian subcontinent, killing 17,000 people."

In the ensuing twenty years, many improvements were made in the meteorological department and administrative systems. So now, despite the big storms, the damage seems to be relatively low. But if a storm hits Mumbai directly, there is still a fear of huge losses.