Back-to-back heatwaves in South Asia no coincidence, says new IIT-Bombay study

Researchers at IIT Bombay, in collaboration with Germany’s Johannes Gutenberg University, have uncovered the complex climatic mechanisms behind back-to-back extreme heatwaves that scorched India, Pakistan, and Afghanistan (South Asia) in March- April 2022. The study, published in Journal of Geophysical Research: Atmospheres, found that the two heatwaves were driven by different factors, yet one worsened the other.

The March-April 2022 heatwave conditions were fuelled by high-altitude wind patterns, where energy transfer between jet streams intensified temperatures. However, the April heatwave had a more dangerous trigger, dry soil left behind by the previous month’s heat. Prof. Arpita Mondal from IIT Bombay explained that when soils are dry, more solar energy is used to heat the air rather than evaporate moisture. This, she noted, sets off a vicious cycle where one heatwave can intensify the next.

Researchers emphasise the urgent need for improved forecasting systems as climate change continues to amplify extreme weather across South Asia. The study highlights a worrying feedback loop, early-season heatwaves dry out the soil, reducing its ability to cool the air through evaporation. As a result, subsequent heat events become more severe, with land heating up faster and more intensely.

Understanding these underlying processes, experts say, is crucial for enhancing early warning systems and boosting regional preparedness. Better insights into these patterns could play a key role in minimising the impact of future heat waves.