Over a Fifth of Excess Deaths Linked to Heatwaves Over Past 30 Years Occurred in India: Study

Research shows that heatwaves cause over 1.53 lakh deaths annually, with India experiencing the highest share. Heatwave-related excess deaths account for about a third of all heat-related deaths globally. To bring down such a huge number of deaths, comprehensive strategies for adaptation and mitigation, including climate policy, early warning systems, urban planning, and community engagement are required at country and global levels.

New Delhi: More than 1.53 lakh deaths a year were associated with heatwaves around the world, with over a fifth of these deaths - the greatest share - coming from India, according to new research looking at data over 30 years since 1990. India was followed by China and Russia, with each experiencing roughly 14 per cent and 8 per cent of these heatwave-linked excess deaths, respectively.

The study, led by Monash University, Australia, found that heatwave-linked excess deaths accounted for about a third of all heat-related deaths and 1 per cent of total deaths globally. Researchers also found that of the overall 1.53 lakh excess deaths occurring every summer, close to half came from Asia and more than 30 per cent from Europe. Further, the largest estimated death rates (deaths per population) were seen in regions with dry climates and lower-middle incomes. The findings are published in PLoS Medicine.

"During the warm seasons from 1990 to 2019, heatwave-related excess deaths accounted for 153,078 deaths per year, a total of 236 deaths per ten million residents or 1 per cent of global deaths," the authors wrote. For the study, the researchers used data from the UK-based Multi-Country Multi-City (MCC) Collaborative Research Network that included daily deaths and temperatures from 750 locations across 43 countries.

Comparing the decade up to 2019 with that up to 1999, the duration of heat waves each year was found to have extended from 13.4 to 13.7 days on average around the world, with average ambient temperature warming by 0.35 degrees Celsius every decade. The researchers said that while previous studies have quantified excess deaths due to heatwaves locally, they have not compared these estimates across the globe over a prolonged duration.

"Heatwaves are associated with substantial mortality burden that varies spatiotemporally (with space and time) over the globe in the past 30 years," the authors wrote. The findings show that government actions taken to enhance health sector adaptation and resilience can have potential benefits, the authors said. They called for a "comprehensive approach" tackling not only immediate health risks during heatwaves but also implementing long-term strategies to minimise vulnerability and inequalities across communities.

"The strategies include climate change mitigation policy, heat action plans (e.g., heat early warning system), urban planning and green structure, social support program, healthcare and public health services, education awareness, and community engagement and participation," the authors wrote.