Almost 90 per cent of Indians are more vulnerable to public health issues, food shortages and increased risks to deaths due to the deadly heat waves fuelled by climate change in 2022, research by the University of Cambridge revealed on Thursday.

The study, published in the ‘PLOS Climate’ journal at a time when several parts of India are already in the throes of rising temperatures, points out that India currently uses a national Climate Vulnerability Indicator (CVI) to measure climate vulnerability and make plans for the adaptation.

The CVI includes different socioeconomic, biophysical, institutional, and infrastructural factors but it doesn't have a physical risk indicator for heat waves, which it warns is a key missing factor that would help policymakers consider how extreme heat actually impacts the Indian population.

“A heat stress measure which identifies the impacts and the parts of India where the population is most vulnerable to recurring heat waves would help to make state Heat Action Plans being created across India more effective,” said the report’s first author Dr Ramit Debnath, Cambridge Zero Fellow at the University of Cambridge.

“So, we could figure out how extreme heat really affects people and in which parts of the country,” he said.

The study is the first to include a “heat index” to measure the recurring impacts of Indian heat waves on the country’s population.

The index measures how hot the human body feels relative to the surrounding conditions when humidity and air temperature are added together.

It suggests that the CVI underestimates the main risks and threats of heat waves to the Indian population because it does not include any kind of heat stress measure.

This missing element also makes it harder to identify areas of the country, like Delhi and other larger urban areas that are most vulnerable. Co-author Dr Ronita Bardhan, Associate Professor of Sustainable Built Environment at the University of Cambridge, said: “Delhi’s heat vulnerability will exaggerate indoor overheating, especially for those people in affordable housing who have fewer resources to cool themselves. Social cooling practices need to be understood to mitigate and adapt to heat-related health and energy burdens.” Researchers used publicly available data on state-level climate vulnerability indicators from the Indian government’s National Data & Analytics Platform to classify severity categories.

They then compared India’s progress on its UN Sustainable Development Goals (SDGs) over 20 years between 2001 and 2021 with extreme weather-related deaths during that period.

Results showed that India's global ranking according to the United Nations Sustainable Development Group has gone down in the last two decades because it hasn't met 11 of the 17 UN Sustainable Development Goals, all of which were important for SDG 13 (Climate Action).

Previous studies have shown that India’s frequent heat waves are a growing burden on its economy and public health resources.

Long-term predictions show that the heat waves will affect more than 300 million people by 2050 and lower the quality of life for almost 600 million Indians by 2100. But there has not been enough focus on their short-term effects and the plans for dealing with heat waves, the research warns.

The study also found that not having a physical risk measure for heat waves can slow progress in SDG 2 (Zero Hunger), SDG 3 (Good Health and Well-Being), SDG 5 (Gender Equality), SDG 8 (Decent Work and Economic Growth), SDG 9 (Industry, Innovation and Infrastructure), SDG 10 (Reduced Inequalities), and SDG 15 (Life on Land).

On a smaller scale, a case study of urban sustainability by the researchers found that residents of Delhi endured some of the most difficult conditions, with almost all of the National Capital Region (NCR) hitting danger levels on the index during a heat wave. Its suggested solutions include improved measurement, preventing overheating of low-income housing, building heat wave resilience partnerships, and learning from international action plans.

The research was supported in part by the Bill and Melinda Gates Foundation, the Quadrature Climate Foundation, the Laudes Foundation, the Keynes Fund and the Africa Alborado Grant.

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