Severe Indian heatwave will bake a billion people and damage crops

More than a billion people are facing a severe heatwave across India this week, which will have wide-ranging consequences for the health of the most vulnerable and will damage wheat harvests.

Temperatures in the mid-to-high 40s°C are forecast for much of the country in the coming days, with the India Meteorological Department (IMD) issuing heatwave warnings for several states.

The UK Met Office says that temperatures are currently above average in India and that this will probably continue into the coming week. India is entering a season ahead of the monsoon’s arrival when heatwaves are common, the Met Office says, but this year it follows a period of unusually early sweltering conditions in India.

March was record-breakingly hot, with a national average maximum temperature of 33.10°C, beating the 33.09°C set in March 2010. R K Jenamani, head of the national weather forecasting centre at the IMD, says that the recent heatwaves have been notable because they occurred during a La Niña weather pattern – which usually has a cooling effect globally – while the 2010 records took place during an El Niño, which has a warming effect.

“It’s really bad,” says Arpita Mondal at the Indian Institute of Technology Bombay, Mumbai, where she says high humidity means that temperatures around 32°C feel more like 38°C. “It’s very tiring and stressful,” she adds. What is notable is how early the heatwaves have come, she says. They are also unusually widespread, baking almost the entire country rather than just India’s two usual heat hotspots, the central north-western region, including Rajasthan, and the south-east, including Andhra Pradesh.

The recent heat is likely to have been exacerbated by climate change, says Mondal, though it is too early for any specific research attributing the event to global warming. She points out that last year’s Intergovernmental Panel on Climate Change report found heatwaves across land globally had become more intense and frequent with high confidence that human activity is to blame.

Local weather patterns are playing a role, too. Jenamani says there has been an absence of storms that can bring rainfall from the Mediterranean to northern India, known as western disturbances, with just five occurring in March and all of them dry. March also saw lower than usual thunderstorm activity over most of India, he adds. R Krishnan at the Indian Institute of Tropical Meteorology says the unexpectedly prolonged La Niña may also be contributing.

Research suggests India is seeing a growing number of extreme heat days. Kim Knowlton at the NRDC, a non-profit, says an ongoing update of a study by an IMD team found 600 heatwave days between 2011 and 2020, compared with 413 between 1981 and 1990. “While the months of March to June have always been very hot, climate change is fuelling more extreme temperatures,” she says.

The impacts go beyond making life almost unbearably hot for people working outdoors in everything from construction to rickshaws and farming. The heat also threatens wheat harvests at a time when global supplies of the crop are already under pressure due to Russia’s invasion of Ukraine. Heatwaves have hit India’s biggest wheat-producing states, Haryana, Uttar Pradesh and Punjab, with officials in the latter warning production targets will be missed after wheat was found shrivelled. Temperatures above 34°C cause heat stress for wheat, and future climate change is projected to reduce India’s wheat yields.

While climate scientists and others on social media have compared the heatwave with a deadly fictional version in a novel by the author Kim Stanley Robinson, better early warning systems in India than in the past – and more people acting on them – appear to have curtailed deaths. Jenamani reports 11 deaths in Maharashtra and two in Rajasthan, but shares data showing much lower deaths in April than during a similar heatwave in April 2010, which he attributes to better forecasts and alerts.

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