As this year’s summer, with its extended heat waves and record temperatures, warns, how to adapt to a warmer world is no longer a hypothetical question. A new study by World Weather Attribution says climate change has made a 30-day heat wave in South Asia 45 times more likely and 0.85o C hotter. Experts say we need to rethink the kind of houses we live in and offices we construct, how we grow our crops and the way we look at the impact of heat on our bodies, even as we tackle reducing the use of fossil fuels.
Warmer Homes, Cities
In the Australian mining town of Coober Pedy, where temperatures go up to 50o C , the homes of about half the population are always a cool 19-25o C. This is because about 50% of the population live underground, in dugout homes excavated into hillsides. Chitra Vishwanath, a sustainability-focused architect, says India, too, should make better use of underground spaces, in the face of rising temperatures. “Underground is multivalent—it gives you material to build with and a cool space,” says Vishwanath, whose firm, Biome Environmental Solutions, designs work and living spaces in basements to avail of material and cool interiors.
Building underground cannot happen all over—for example, not in areas where the water table is high or where there is no significant variation in temperatures. But Vishwanath’s point remains: we are not designing buildings according to the climate
There was a time when we believed we could artificially control indoor climate by air conditioning or heating, when we used concrete, steel and glass and thought we need not look at the traditional way of building, says Benny Kuriakose, an architect focused on sustainability and conservation. But over the years, there has been a growing realisation about the importance of designing buildings that allow natural cooling and the fact that artificial cooling contributes to global warming. Kuriakose says we persisted with these buildings although studies as far back as three decades ago showed these create urban heat islands, a phenomenon of higher temperatures in cities due to buildings and pavements absorbing and re-emitting heat.
With studies showing that dense, taller developments trap more heat, we need to shift to mid-rise, high-density development, says Vaidya of IIHS. Another simpler measure, implemented in areas in Gujarat, Telangana and, earlier, Delhi is the cool roofs programme, where roofs are painted white so that heat is reflected back. Vaidya says Indian cities also need to adopt open grid paving where there will be a little grass growing between paved areas. “This will allow water to percolate and increase reflectivity of the surface.”To prevent the sun from falling directly on walls, traditional architecture had features like an overhang and verandahs, says Kuriakose. While he says he does not take a romanticised view of the past, if no adaptation measures are taken, we could face a situation where the government bans construction of new buildings. “It will become a question of survival.”Too Hot to Work?
Rising temperatures are a threat to economies around the world but, in India, some factors exacerbate the risk. Among these is the combination of heat and humidity, or the wet-bulb temperature, which captures the stress on the human body. This is not sufficiently understood or thought about in India, says Mekala Krishnan, partner, McKinsey Global Institute.
Krishnan is the co-author of a 2020 report titled “Will India get too hot to work”, which looked at the risks to human life and the economy posed by extreme heat and humidity. “We calculated that outdoor-exposed sectors make up about 50% of GDP and 75% of the workforce. So by 2030 (in a high-emission scenario) about 2.5-4.5% of India’s GDP could be at risk from the chronic shift in heat and humidity levels,” she says on a Zoom call from the US. This includes agriculture, mining, construction and transportation, among others, and could impact $150-250 billion of GDP.
This reliance of the economy on labour-intensive and outdoor-based work, the scale of the problem due to the population and the fact that events like heat waves tend to occur over large expanses heighten India’s challenges.
Currently, about 10% of Indian households have air conditioners, projected to go up to only 40% by 2037. In such a scenario, India might have to set up cooling shelters that can be accessed by the public during a heat wave. “Construction might have to switch to evening, as could road work,” says Vaidya.
The low-hanging fruit in mitigating the impact of heat, even on the workforce, are increasing trees and having more reflective surfaces. These, say Krishnan, would be easier to implement and would not require large-scale mobilisation. A silver lining, she says, is that since a lot of India is still being built, there is an opportunity to integrate climate risk into planning and design.
Heat & The Human Body
Halfway through the long election season, Union Minister for Road Transport and Highways Nitin Gadkari collapsed while delivering a speech in Yavatmal in Maharashtra, which was experiencing heatwave conditions. The minister received aid immediately but the incident underlined the vulnerability of people to extreme heat.
“There are two types of heat stroke —direct or exertional heat stroke, when you are working in direct sun or sitting in direct sunlight (for an extended period). The second is indirect or non-exertional heat stroke, which is more insidious and happens largely to older people or those with comorbidities,” says Dr Dileep Mavalankar, honorary distinguished professor of public health, Indian Institute of Public Health, Gandhinagar. About 80-90% heat stroke cases fall in the second category, he says.
Warmer temperatures also mean higher risk of gastrointestinal diseases due to food spoilage and the spread of infectious diseases due to less frequency of washing hands etc., due to water shortage. Higher temperatures can be conducive to certain vectors as well and allow viruses to be in circulation for longer, with diseases such as malaria appearing in climates that have become warmer.
According to the National Crime Records Bureau’s 2022 report, there were 730 deaths due to heat/sun stroke. But public health officials say there needs to be more training and awareness in reporting heat-related ailments. A senior official with the National Centre for Disease Control, who requested anonymity, says there are challenges in reporting since the diagnosis is purely clinical, not laboratory-based. “Routine reporting is very important. If you report heat-related illness late, you will miss the correlation between the temperature and the condition.”
Hospitals must be prepared with heat stroke rooms, since cooling down patients at the earliest is critical. In Ahmedabad, hospitals have heat wards in summer and all ambulances have ice packs, which can be used to cool patients of heat emergency while being transported, says Dr Mavalankar. It’s critical to make people aware that heat can kill, he adds. “People think that Indians are used to heat. But the indirect effect of heat and non-exertional heat stroke are not sufficiently understood in India.”
The Food We Eat & Grow
There was a time when summers called for more fermented food and liquid food such as millets in semi-solid form mixed with curd, or ragi that has been fermented, says R Rengalakshmi, executive director, area operations, MS Swaminathan Research Foundation. Farming families would also have dried pumpkin and brinjal in the absence of fresh produce. “These fermented foods are good for our gut health. But these traditional food practices have almost vanished,” she says. As summers get more intense and heat waves are prolonged, impacting vegetable and other crops, there might be a case to revisit some of these practices.
Among India’s major food crops, wheat is the most vulnerable to heat, requiring milder temperatures during grain-filling period. If temperatures rise at that time, the yield reduces quickly, says Avinash Kishore, senior research fellow, International Food Policy Research Institute. With most of the wheat harvested before peak summer temperatures, the bulk of the crop is considered to have escaped the worst of the heat. However, the same could not be said of vegetables and fruit. Vegetable crops in south Bengal, reeling from heat waves, are reported to have suffered extensive damage.
In Kerala, which is facing its first official heat wave, the agriculture department has estimated crop loss worth `250 crore in over 46,000 hectares. “In the summer, it is largely vegetables that are affected. Extreme heat reduces the photosynthetic ability of plants and reduces soil moisture, affecting the crop,” says Rengalakshmi. IFPRI’s Kishore says the impact of extreme heat on the dairy sector needs more research.
To mitigate the impact of warmer temperatures, he suggests investing more in irrigation and research into heat-resistant varieties. Greater crop diversification and altering our trade policies could also help. “As we grow richer and diets change, it is inevitable that we’ll become a net importer. We need to decide what we will produce, export and import, keeping our interests in mind,” he says. Rengalakshmi says adaptation strategies should include changes in cropping patterns and improving the microclimate of regions through more green cover. But adaptation strategies can have a limit, adds Kishore. “If some of the worst predictions by climate scientists come true—of temperatures rising 3-4 degrees above the long-term normal—I don’t think we will be able to adapt.”