AHMEDABAD, India — It’s a few minutes past 10 in the morning, and already the intense heat is setting in around the outskirts of Ahmedabad, a city in Western India. Sapnaben Chunara, a 30-year-old mother with three children, finishes her morning chores and retreats to the comfort of a neem tree’s shade, known for its resilience to drought and soaring temperatures.
Chunara spends most of her time outdoors in Vanzara Vas, a neighborhood populated by around 800 low-income families. Her dwelling, with its metal roof, becomes unbearably hot, often even more so than the outside temperatures, which consistently exceed 40 degrees Celsius (104 F). These extreme temperatures were unusual but have become common, with this year’s heatwave starting three weeks earlier than previous years and temperatures already reaching 43 degrees Celsius (109.4 F) by early April.
“The heat sometimes becomes overwhelming,” Chunara says, as her black smartwatch gleams against her vibrantly colored bangles and sari. Chunara is part of a study involving 204 Vanzara Vas residents, each given a smartwatch to assess how extreme heat affects vulnerable communities worldwide. These devices monitor heart rate, pulse, and sleep patterns, complemented by weekly blood pressure checks.
To combat heat, researchers have applied reflective paint to some roofs, creating “cool roofs” and will measure their effectiveness using indoor heat sensors. This project aims to help poor households survive India’s sweltering summers. Chunara, whose home lacks a cool roof, wears her smartwatch with hope, anticipating that the study’s findings might lead to practical solutions for her neighborhood.
In cities like Ahmedabad, scorching summers have always been a challenge, but now the heat is approaching lethal levels. In 2010, almost 1,300 unexpected deaths in the city were linked to extreme heat. The escalating global temperatures due to carbon emissions primarily from fossil fuels are exacerbating such conditions, especially in already hot regions.
A 2023 study warned of a possible 370% rise in global heat-related deaths if average temperatures climb close to 2 degrees Celsius (3.6 degrees Fahrenheit) above pre-industrial levels. South Asia, Southeast Asia, and Africa could be most affected. Abhiyant Tiwari, a climate expert involved in the research, notes the growing divide between wealthier and poorer communities in dealing with heat.
After the 2010 disaster, Ahmedabad officials, with public health experts, developed an action plan to alert residents to hazardous heat levels and prepare hospitals for heat-induced conditions. This plan has been replicated throughout India and parts of South Asia.
The last two years have marked the hottest globally, pushing researchers to find solutions that protect the most vulnerable populations from increasing heat. The Ahmedabad research is part of a larger global study examining the heat’s impact on vulnerable communities in places like Burkina Faso, the Pacific island of Niue, and Mexico’s Sonoran desert.
Aditi Bunker, an environmental health researcher affiliated with universities in New Zealand and Germany, leads the global study. More than 1.1 billion people live in informal settlements akin to Vanzara Vas, making them especially susceptible to climate change’s effects. Bunker emphasizes addressing these challenges through research.
In Ahmedabad, Bunker works alongside Indian researchers to gather crucial health data. If cool roofs prove effective, the intention is to extend this approach across all homes, helping inform policymakers globally of such viable solutions.
Vanzara Vas residents like Chunara and her neighbor, Shantaben Vanzara, remain optimistic about the study. Despite her diabetes worsening due to the heat, being part of the research offers Shantaben some relief, particularly after her roof was painted, allowing some precious hours of sleep.
Chunara reflects on how temperatures used to be more predictable. “Now, everything is uncertain,” she remarks. “The only certainty is that the heat intensifies every year.”