THE NEW EXTREME EVENT

Wind circulations are slowing in a warming world, adding to the frequency and intensity of extreme events

ON MAY 29, 2024, just as large parts of northern and central India were in the grip of extreme heatwave conditions, the Mungeshpur automatic weather station of the India Meteorological Department (imd) in north Delhi recorded 52.9oC. It was dubbed as the highest-ever maximum temperature recorded in the country. While the weather agency promptly refuted the reading, explaining that the anomalous temperature “could be due to error in the sensor or the local factor”, several other weather stations in Delhi and the National Capital Region that day recorded between 45.2oC to 49.1oC. Gujarat and Rajasthan suffered the worst, with 12 and 11 days of heatwaves, respectively, between May 16 and 26. Several cities shattered their all-time heat records for May. This includes Chandigarh, where temperature soared to 46.7°C on May 29, breaking its record of 46.5°C in May 1988.

Heatwaves are usual in these parts of the country during the summer season. "But the excess heat that made them punishing this year came from the warm winds blowing in from the Arabian Sea," says Raghu Murtugudde, professor of climate studies at the Indian Institute of Technology, Bombay and emeritus professor at the University of Maryland, US. According to research published in Earth Science Reviews in March 2022, the Arabian Sea has warmed by 1.2°C to 1.4°C in the past few decades. Usually, the ingress of warm winds from the Arabian Sea on the west is opposed by the strong trade winds from the northeast. But this year, it was different.