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.
Heatwaves cause more than 1.53 lakh deaths worldwide each year, with India accounting for more than a fifth of these deaths - the highest percentage - during the last 30 years, according to new research. India was followed by China and Russia, which had around 14% and 8% of the heatwave-related extra mortality, respectively.
The study, headed by Monash University in Australia, discovered that heatwave-related excess fatalities accounted for around one-third of all heat-related deaths and one percent of overall deaths worldwide.
Researchers also discovered that over half of the 1.53 lakh additional fatalities that occur every summer originated from Asia, with Europe accounting for more than 30%. Furthermore, locations with drier weather and lower-middle incomes had the highest estimated mortality rates (deaths per population). The findings were reported 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 researchers stated.
The researchers conducted the analysis using data from the UK-based Multi-Country Multi-City (MCC) Collaborative Research Network, which includes daily mortality and temperatures from 750 sites in 43 nations.
When comparing the decade from 1999 to 2019, the average length of heat waves each year increased from 13.4 to 13.7 days worldwide, with average ambient temperature rising by 0.35 degrees Celsius per decade.
The researchers stated that, whereas earlier studies have documented increased mortality caused by heatwaves locally, these figures have not been compared globally over a lengthy period of time.
"Heatwaves are associated with substantial mortality burden that varies spatiotemporally (with space and time) over the globe in the past 30 years," the researchers said. The authors concluded that government initiatives to improve health sector adaptation and resilience can have potential advantages.
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.