India's climate crisis: Early heatwaves, Himalayan glaciers melting and a biodiversity collapse

Subscribe to enjoy similar stories. Climate Change & You’ is a fortnightly newsletter by Bibek Bhattacharya and Sayantan Bera. Subscribe to Mint's newsletters to get them directly in your email inbox. Dear Reader, Even a few years ago, it would have seemed ridiculous to suggest that Delhi might hit a daytime high of 40 degrees Celsius in late March.

The climate crisis, though, has a way of turning even the most unthinkable weather phenomena into the new normal. And so it came to pass that on 26 March, Delhi touched a scorching 40.5 degrees Celsius. It was a seasonal high, beating the heat record from just the previous day—that of 37.1 degrees Celsius.

The daytime temperature on the 26th was 6.3 degrees Celsius above normal for this time of the year, and over the years, the hottest March day has been getting hotter: 37.8 degrees Celsius in 2024 and 34.3 degrees Celsius in 2023. But this isn't an isolated anomaly. Heat has been striking ridiculously early all across India, and it is now clear that our seasons are shifting, sometimes by a whole month.

This shift in seasons (or the complete erasure of specific seasons) is striking enough that even ordinary people can feel and comment on it. However, this is also evident in hard data. Hindustan Times analysed the India Meteorological Department's (IMD) temperature-gridded data and found that the key heat threshold temperature of 40 degrees Celsius arrives earlier across the country and lasts longer. The analysis found that 56.7% of the regions that crosses 40 degrees Celsius each year hit the mark a week in advance.