Deadly heat waves fueled by climate change are threatening India’s development and risk reversing its progress on poverty alleviation, health and economic growth, a new study has found.
Heat waves have already critically impacted the country, leading to power outages, increased dust and air pollution, and accelerated glacial melt in the north of India, researchers from the University of Cambridge said in the study published in the journal PLOS Climate on Wednesday.
Since 1992, more than 24,000 people have died because of heat waves in India, the study said.
And the impacts are expected to get worse as heat waves become more frequent, intense and lethal due to the climate crisis.
“India is currently facing a collision of multiple cumulative climate hazards,” said the researchers.
“Long-term projections indicate that Indian heat waves could cross the survivability limit for a healthy human resting in the shade by 2050.”
The study shows that millions more people in India are vulnerable to climate change than first thought. More than 90% of the country could be severely impacted by heat waves, falling into an extreme heat “danger” zone, according to the heat index, the study found.
The heat index is how hot it feels and considers both air temperature and humidity to assess the heat’s impact on the population.
Last year, India experienced a searing heat wave, during which parts of the country reached more than 49°C (120°F).
In 2022, India experienced its hottest April in 122 years and its hottest March on record, the study said. And it experienced extreme weather on 242 out of 273 days between January and October 2022, the researchers found.
Such repeated heat stress will upend millions of lives and livelihoods.
“Estimates show a 15% decrease in outdoor working capacity … during daylight hours due to extreme heat by 2050,” the study found. “The increased heat is expected to cost India 2.8% and 8.7% of its Gross Domestic Product (GDP) and depressed living standards by 2050 and 2100, respectively.”
By mid-century, 70 Indian cities are expected to have more than 1 million inhabitants, according to the study.
Extreme heat will pose a threat to the energy security and health of those people, and reverse progress in inequality and poverty reduction, the researchers found.
“My family in Kolkata is suffering from current heat waves leading to frequent load shedding,” said the author of the study, Dr Ramit Debnath, in a reference to enforced power outages that reduce strain on the grid. “The climate-energy nexus is becoming more relevant,” he added.
Typically, it’s the poorest and most vulnerable who will suffer the most.
Heat waves will “have unprecedented consequences on the low-income population” the study said. As an example, the authors point to the rapidly urbanizing capital New Delhi, which “has a high level of construction activities, mostly involving a low-income labor force, who are also at severe risk from heat wave impacts.”
While India has a “climate vulnerability index” through which it assesses its vulnerability to the climate crisis, the authors believe this underestimates how heat waves impact the country’s development.
India has committed to the UN’s Sustainable Development Goals, a list of 17 objectives that include cutting poverty, hunger, inequality and disease, as well as promoting health, education and sanitation.
By not understanding the true threat of heat waves on its population, India risks missing out on those goals.
The study’s co-author Professor Ronita Bardhan said the recommendations could be used to build heat resilience for low-income housing as “these communities are most vulnerable to heat impacts.”
“Heat-health packages for low-income and slum dwellers are specifically critical as we show heat waves have devastating impacts on urban sustainability,” she said.
Another practical application is urban greening strategies around highly dense areas, which “can provide relief from urban heat island effects,” Bardhan said.
The authors stress “urgency” in recommending India update its extreme weather assessment to include the heat index and its impact on India’s sustainable development.
“India has demonstrated tremendous leadership in scaling up heat action plans in the last five years by declaring heat waves a natural disaster and mobilizing appropriate relief resources,” the authors said.
But “as the heat waves in India and the Indian subcontinent become recurrent and long-lasting, it is high time that climate experts and policymakers reevaluate the metrics for assessing the country’s climate vulnerability.”