As heat waves grow more common, frequent, and intense in India and around the world, researchers say it’s having a disproportionate effect on some of the world’s poorest communities.
In India, that harsher impact is being felt in the nation’s slums, which researchers say can be as much as 6°C (42.8°F) warmer than other parts of the city
“In the slums, it is so difficult to step out and find shade on a hot summer day,” Anshu Sharma said. “It is so congested. The houses are often made of tin sheets, which heat up much faster compared to other materials.”
Sharma is the co-founder of SEEDS, a New Delhi-based disaster response and preparedness non-profit organization, which has measured the temperature disparity between the slums and other parts of the city.
Since 2017, SEEDS has been working with communities most vulnerable to heat waves, to help people come up with solutions to beat the heat. And now, with the support of Microsoft’s AI for Humanitarian Action grant, SEEDS has developed an artificial intelligence (AI) model to predict the impact of multiple hazards like cyclones, earthquakes or heat waves in any given area.
The model, called Sunny Lives, has generated heat wave risk information for around 125,000 people living in slums in New Delhi, India’s sprawling capital, and Nagpur, a central Indian city susceptible to intense heat waves.
Here’s the story of how SEEDS married cutting-edge technology, shoe-leather surveys, and collaborative project management to raise awareness about what is often an invisible enemy.
An invisible enemy
In humans, heat stress is known to cause higher blood pressure, extreme fatigue, and sleeping troubles. The risk of heat stress is highest outdoors, between noon and 4 p.m. But, alarmingly, in some cases staying indoors might be more dangerous.
Quite simply, if you don’t live in a house made from the right kind of materials, it could be hotter indoors than it is outdoors. Sharma shared some numbers to drive home the point.
“Suppose the outdoor temperature is about 38°C (100.4°F),” he said. “If you’re in a tin shack in a slum, the indoor temperature can be as high as 45°C (113°F). And it’s the older people, and young children, who spend the day indoors, that suffer.”
Central to the problem is the fact that most makeshift construction materials used in urban slums trap more heat, thus increasing the indoor temperature. The roofs are often made of tin sheets and houses are crammed together without windows or ventilation.
A study recently published in Nature examined the indoor temperature variations in different housing types across five low-income locations in South Asia. One of the key findings from the study was about the monthly temperature variation in tin-roofed houses in a village in the western Indian state of Maharashtra: in the months of May and June, the temperature was a good three or four degrees Celsius (37.4°F-39.2°F) higher compared to the outdoor temperature.
That’s been an especially concerning scenario this year.
Blazing summers in the Indian subcontinent are considered the norm, but even by the region’s own standards, the heat this year was intense and widespread. In mid-May, the India Meteorological Department reported record high temperatures between 45°C (113°F) and 50°C (122°F) in several parts of the country.
Experts say such intense heat waves are likely to continue. According to a study published in the Weather and Climate Extremes journal last year, India saw more than double the number of heat waves between 2000-2019 than it did between 1980-1999.
“In the future, these kinds of heat waves are going to be normal,” Professor Petteri Taalas, the secretary general of the World Meteorological Organization (WMO), said in a recent report.