India shouldered the highest burden of heatwave-related excess deaths globally accounting for more than 20 per cent of the total 1.53 lakh such mortalities surpassing both China and Russia in this aspect in the last three decades from 1990 to 2019.
A research conducted by Australia-based Monash University said that the impact of heat waves on India is particularly severe due to a combination of geographical, climatic, and socioeconomic factors. In contrast, China and Russia,each experienced roughly 14 per cent and 8 per cent of these heat wave-linked excess deaths, respectively.
Overall, more than 1.53 lakh deaths a year were associated with heat waves around the world. The study found that heatwave-linked excess deaths accounted for about a third of all heat-related deaths and 1 per cent of total deaths globally.
Needless to say, overall 1.53 lakh excess deaths occurred 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.
The high incidence of heatwave-related mortality in India is reflective of several factors, including the country’s large population, its geographical location, and the prevalence of extreme temperatures, particularly during the summer months.
Additionally, socioeconomic factors such as poverty, inadequate access to healthcare, and limited infrastructure exacerbate the vulnerability of certain segments of the population, particularly those living in urban slums or rural areas with limited resources. The authors explained that “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.”
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 including India.
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 heat waves locally, they have not compared these estimates across the globe over a prolonged duration.
The authors have called for a “comprehensive approach” tackling not only immediate health risks during heat waves 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,” they said.
The study echoes findings of a recent report by the World Meteorological Organization (WMO) which said in India alone, severe heat waves in April and June resulted in about 110 reported fatalities due to heatstroke in 2023.
Yet another analysis by an international team of leading climate scientists from the World Weather Attribution group has called for urgent measures to mitigate the impact of heat waves which are likely to intensify in coming years.
“Some countries, such as India, have comprehensive heat action plans in place. Yet, to protect some of the most vulnerable people, these must be expanded with mandatory regulations.
Workplace interventions for all workers to address heat stress, such as scheduled rest breaks, fixed work hours, and rest-shade-rehydrate programs (RSH), are necessary but have yet to become part of worker protection guidelines in the affected regions,” it said.
