Heatwaves are becoming more common in southern India, according to a recent study by the Centre of Earth, Ocean and Atmospheric Sciences, School of Physics at the University of Hyderabad. The study examined daily temperature data from 1970 to 2019 across four climatic zones in India. The researchers found that days with higher temperatures are increasing during summer each year, while days with lower temperatures are decreasing during winter. Heatwave events are increasing at 0.6 events per decade, while cold waves are decreasing at 0.4 events per decade.
The study used four broad climatic zones: montane (mountainous regions), arid regions of Rajasthan and semi-arid climate of Gujarat, humid subtropical (Indo-Gangetic basin), and the southern peninsular region. The authors note that opposite trends in heatwaves and cold waves need further study. Heatwaves are more common in the arid and semi-arid climatic region of North India but now that part was witnessing a fall in heatwaves while the cold wave conditions were on the rise. Meanwhile, the southern peninsular region was witnessing more heatwave conditions during summer and less cold wave conditions during winter.
The team did not investigate factors attributed to the rise in heatwaves in various south Indian states such as Telangana and Andhra Pradesh, but suggest that aerosols and moisture in the air may be contributing to this new phenomenon.