Why has 2024 summer arrived early, and why is Kerala unbearably hot

Illustration: Manorama

Thiruvananthapuram: Wild animals roaming around in human settlements even by the last week of January was an early sign that the summer of 2024 was possessed by evil spirits. There were already warnings that abnormal heat was precipitating a food and water crisis within the forest.

By the second week of February, the heat felt across Kerala was intense like never before during February. The 38.5 degrees Celsius recorded in Kottayam and Kannur by the middle of February was the highest ever the mercury had shot up in Kerala during February; it continues to be 38 degrees Celsius in the Palakkad and Kollam districts.

The heat seems both unrelenting and intensifying. 2023 was the hottest year in 124 years and India Meteorological Department (IMD) has warned of a hotter summer in 2024. The IMD's 'Outlook for the Seasonal Temperatures During the Hot Weather Season (March to May), 2024' put out on March 1 said that "above normal monthly (March 2024) minimum temperatures are likely over most parts of the country".

As it turned out, the summer is not just hotter it has also arrived at least a month in advance.

Power gluttony
Like animals, humans too have behaved in abnormal ways. Power consumption in Kerala crossed 100 million units in the first half of March. Never before has daily consumption crossed 90 MU in March.

Power use touched 100 MU on March 11 and has since kept inching up by the day. On March 13, it was 101.91 MU, which is close to the record. On March 14, consumption dropped a bit, to 101.51 MU. The highest-ever daily consumption recorded was on April 19, when the intake was 102.99 MU.

Reason One: Boy’s mischief
This unusually high temperature can be traced to a phenomenon linked to Jesus Christ. It is called El Nino.

Every seven years, during Christmas time, the sea surface temperatures over the Pacific Ocean near the equator warm up to an unusual degree, by 3-4 degrees Celsius. The Spanish sailors christened this Christmas time phenomenon El Nino, meaning 'the boy'.

2023 was an El Nino year, and the condition has spilled over into 2024. When 'the boy' exerts his influence, hundreds of thousands of square kilometres of the Pacific Ocean will heat up. When the sea surface temperature rises, the heat would spread to the air above it causing the air laden with water vapour to move up. This leads to the formation of rain clouds. So there will be rain in the east and central regions of the Pacific Ocean, in South America and bits of Europe.

Illustration: Manorama

While he brings rain to certain places, 'the boy' can play mischief in other areas. While he sends up air over the Pacific he would pull it down in areas far away, especially over the Indian landmass.

Dr M G Manoj, a scientist with the Advanced Centre for Atmospheric Radar Research - CUSAT, said atmospheric movements across the globe were connected. "When the air moves up over the equator in the Pacific Ocean a chain reaction happens that pulls down the air over the Indian landmass," Manoj said.

This clockwise descending movement of air is called anti-cyclone. "Only if there is ascending motion will rain clouds form. When there is descending motion, there will be a clear sky and no rain," Manoj said. Cyclonic movement, on the other hand, creates rain.

This continuous descent of air during an anti-cyclone creates a compression at the surface of the earth. This causes what scientists call "compressional warming" just above the surface. "When this happens, hot air is not allowed to go up. It will be trapped in the surface causing surface temperatures to boil," Dr Manoj said. This anti-cyclone condition that precipitates compressional warming has been persisting over the Indian landmass, especially South India, since the first week of February.

Reason Two: Sea trouble
This alone is not responsible for the unusual heat. Thanks to global warming, the Arabian Sea that lies along the west coast of India has warmed up to a high degree. Studies say that sea surface temperatures have gone up by one to 1.5 degrees Celsius. Hot atmospheric waves from the Arabian Sea are now blowing over the Kerala coast, amping up the heat in coastal regions.

This intense heat can play havoc with our bodies. In the coming days, mainly because of the heat waves blowing from the sea, humidity is expected to rise.

Hyperthermia threat
Usually, sweating is a cooling mechanism of the body. We use the extra heat in our body to vaporise the sweat and thus bring the body temperature down. But if humidity increases beyond a point, our body would sweat but it would not be able to activate its cooling mechanism.

"When the humidity is high we cannot push out the sweat in our body as a vapour because the atmosphere is already hyper-humid. The body will lose the ability to rid itself of sweat. So we keep sweating. This can lead to a condition called hyperthermia, which is nothing but the overheating of the body," Manoj said.

Glad tidings
The IMD has predicted rain or thundershowers in certain parts of Kerala on March 20 and 21.

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