Kerala's rain pattern has seen a big shift, say experts
An expert said It was high time Kerala gave top priority to environmental impact studies when it takes up developmental projects
The unseasonal downpour last week left a trail of death and destruction in Kerala amid a shift in rain patterns in the state over the last five years. From the 2018 flood of the century to flash floods this month, the change is evident. Experts say the temperature over the Arabian Sea has increased by 1.2 to 1.4 degrees C in the last two decades, increasing the frequency of cyclonic events along the western coast. Usually, the temperature in the Arabian Sea is 1.5 degrees lower than the Bay of Bengal and this is one of the reasons for less cyclonic circulations and low pressure in the Arabian Sea. But of late, the situation is changing. Experts say the warming is not limited to the top layers of the sea.
“...more than 90 of the heat on earth is absorbed by oceans. Usually, temperatures in the Indian Ocean and Bay of Bengal are above 28 degrees C and in the Arabian Sea, it is between 26 to 28 degrees. But the Arabian Sea is warming up fast. It is quite visible in the last decade or so,” said Roxy Mathew, a scientist with Pune’s Indian Institute of Tropical Meteorology.
He said a big shift in rain pattern is quite visible and added Kerala should have been very careful in land use because the state is endowed with many hills and rivers and has a slanting geographical landscape.
The frequency of cyclonic circulation over the Arabian Sea has also increased manifold. There has been a 52% increase in cyclonic movement over the Arabian Sea between 2001 and 2019 and eight per cent during the same period in the Bay of Bengal. The India Meteorological Department statistics show nine cyclones or major depressions were formed in 2020, out of which four were over the Arabian Sea.
Experts say one of the reasons for high temperature is a chemical reaction in the sea induced by pollution. According to a Central Marine Fisheries Institute of India study in 2018, major oceans will have more plastic than fish. By 2050, over 850 metric tonnes of plastics will be found in the sea whereas fish will be 821 metric tonnes. Another Alfred Wegener Institute study says seas near Mumbai, Kerala, and Andaman Nicobar Islands are among the most polluted in the world.
“It is sad in Kerala discussions start only after a tragedy and everyone forgets about it soon. It is high time the state gives top priority to environmental impact studies when it takes up developmental projects. Cloud bursts, flash floods, and landslips are here to stay. The state will have to pay a heavy price if it goes ahead ignoring the climate change signals,” said M G Manoj of the Advanced Centre for Atmospheric Radar Research, Cochin University of Science and Technology.