Seeking to cushion the impacts of global warming is like aiming at a moving target. To make matters worse: the target is now moving faster. Over the last decade or so, there has been a significant acceleration in the rate of warming globally, from about 0.18°C a decade during 1970-2010 to about 0.36°C a decade since. As James Hansen, one of the world’s most well-regarded climate scientists, and his colleagues stated in a research communication in late April, the rate of warming has speeded up because the Earth’s albedo, or reflectivity, has been declining.

There are varied, complex reasons for this. The first, ironically, is cleaner air. Tiny aerosol pollutants in the atmosphere tend to block and scatter sunlight and, hence, reduce the energy absorbed by the earth. However, this masking effect has decreased of late, partly because of stricter sulphur emission norms on marine shipping in recent years, and because China has fairly successfully addressed its air pollution over the past 15 years. Second, both reduced aerosols and global warming have affected cloud formation, reducing clouds’ masking effect as well. Third, Arctic sea ice has reduced as that region has warmed, which has resulted in more solar radiation being absorbed by the much darker water.

The accelerated warming is occurring against the backdrop of continued carbon dioxide and other greenhouse gas emissions that cause global warming in the first place. Because of such global emissions over time, the Indian landmass warmed by 0.9°C during 1901–2024. It has been particularly intense in recent years: 2023 was recorded as the second-warmest year, after 2016, in 122 years of recorded temperatures; 2024 soon took over as India’s hottest year. After a slight dip in temperatures in 2025, this year too began ominously, with heatwaves searing much of India quite early, in April, making it for a while the hottest country in the world.

These are not merely statistical records. Accelerating warming has a bearing on the lives, livelihoods, and health of hundreds of millions of working people across the country, to say nothing of agriculture, productivity, electricity demand, infrastructural resilience, governance, and public health.

In this context, the recent report “Critical Perspectives on Extreme Heat in India”, released by Harvard University’s The Salata Institute for Climate and Sustainability, is timely. It is a compilation of short essays that cover varied facets of extreme heat and ways to adapt to it in the Indian context.

It discusses forecasts for farmers and their challenges; why heat thresholds that trigger adaptation measures ought to be context-specific; the need to prioritise climate-resilient design and materials used in buildings over merely applying reflective paint on “cool roofs”; how heat actions plans (HAPs) that have fared unevenly in different States can be strengthened; insurance payments that are triggered automatically when certain heat thresholds are reached rather than after the damage is done; why workers bear both the highest risks of heat and the costs of adapting to it; what a health agenda for climate adaptation could be; and finally, the need to revamp local and global adaptation finance. For brevity, this article will dwell only on some of these themes.

Dealing with a warmer and more humid world

The first essay, by Peter Huybers, asks why India’s average temperature rise during 1901–2024 was significantly less than the global land average rise over the same period. This is usually attributed to India’s location in the tropics (where warming is less than at higher latitude); surface cooling that has occurred with the spread of irrigation; and the persistence of air pollution in India, in contrast to its reduction elsewhere that has contributed to faster warming.

Huybers correctly points out that warming will accelerate in India as well if the masking effects of air pollution diminish with improved environmental regulation and if irrigation intensity declines. However, the essay only discusses winter months, January mostly. Given that heatwaves and their most harmful effects on people occur largely in summer and pre-monsoon months, one wishes warming trends had been analysed for those periods as well. It is impossible to overstate how harmful, even lethal, more frequent, longer, and more intense heatwaves could be in expansive regions in which tens of millions work outdoors, particularly in socioeconomic contexts of widespread informality of labour and suboptimal nutritional levels.

A warmer world is also a more humid world. This is largely because warmer oceans experience greater evaporation and because warmer air can hold more moisture. This combination of greater heat and humidity is more hazardous than heat alone. As Robert Meade, Aditya Pillai, and Satchit Balsari point out in their essay “How hot is too hot?”, in the Harvard report, there are physiological limits to human capacity to regulate body temperature.

This threshold is widely understood to be 35°C wet bulb temperature (a measure of heat and humidity combined), beyond which someone as fit as Virat Kohli would die if they sat outdoors for a few hours in the shade doing nothing, because the body would unavoidably lose its capacity to expel heat. But such a threshold is an abstract one; physiologies differ, and the elderly, infants, or those with certain ailments have far lower thresholds.

The authors put it well: the questions we first need to ask, they say, are, “Too hot for what?” and, “Too hot for whom?” The answers to these questions depend a lot on how long one works and what work one does. Other than deaths, there are challenges of morbidity and physiological stress starting at far lower levels of heat and humidity, but academic research on what these thresholds are is just nascent in India.

The most significant adaptive response of State governments to extreme heat has been the introduction of HAPs, of which there are approximately 300 across towns and districts with another 100 being developed. Under them, a range of measures including prior heat warnings, wider water distribution, public health interventions, cooling shelters, and so on are activated when the maximum temperature in a place crosses predetermined thresholds. It is widely acknowledged that mortality from extreme heat has fallen in India after these plans were first operationalised little over a decade ago.

While commendably true, we may be underestimating the number of deaths from relentless heat. This is partly because on average in India, 30 per cent of all deaths are reportedly not recorded at all. And when they are, other reasons—most commonly heart attack—are registered as the cause of death, and not the possibly underlying, sustained exposure to extreme heat.

In Europe, where such estimations are made differently (using comparisons with baseline mortality data), it was found that an additional 61,672 people died from extreme heat during a 3-month period in 2022, in a region with a population less than half of India’s. Even though we have a younger population than Europe, it is likely that more people are dying here from heat than we realise. And the number certainly will increase in the future as India warms faster. We urgently need more robust baseline data and methods, improved health systems, and better targeted interventions.

As Aditya Pillai points out in his essay on HAPs, they suffer from poor targeting, whereby the most vulnerable are sketchily covered by, or get left out of, adaptation measures. One problem is that HAPs have inadequate legislative or financial backing. Greater emphasis on incentivising politicians and bureaucrats to act, and more comprehensive implementation across all relevant sectors, along with sanctions for poor implementation, would, he states, be more effective. I would add that greater democratisation in the conception and implementation of HAPs via regular consultations with organisations representing those most affected would also help. Very few States have followed this in practice.

Scaling up adaptation measures

A widely discussed heat adaptation measure is “cool roofs”—the application of white chemical paints on rooftops so more sunlight gets reflected, thereby cooling interiors (similar, in essence, to what Arctic ice does, which the world is fast melting). All examples of cool roof applications I have heard of have been through small, NGO-led efforts, which, however well-intentioned, are carried out for want of resources in a handful of homes in slum clusters.

As with all adaptation measures necessary to tackle so massive and complex a problem as global warming, what is needed is scale. For example, Delhi’s Kashmere Gate bus terminus now has “cool roofs” across 28,674 square feet. This also needs to be carried out where the poor live, in slum clusters in Delhi and elsewhere, wherever feasible. The onus lies on governments to provide subsidies and ensure quality so that a painted roof stays that way for a while.

However, as Rajan Rawal and Radhika Khosla point out in their essay on the built environment, focusing on “cool roofs” alone is inadequate. Other surfaces like walls and windows influence felt temperatures greatly, and, besides, even “cool roofs” do not adequately address dangerous humidity, as mentioned above. It is necessary, they say, to “prioritize other passive design strategies… that address building materials, construction techniques, and spatial configuration”. This is important because deaths from extreme heat happen not just outdoors but also indoors even more commonly, among the elderly and the ill in cramped, poorly ventilated homes.

To once again emphasise scale, I would strongly urge the introduction of an urban version of the National Rural Employment Guarantee Act (NREGA) across towns in India to address this; it has been in operation only in Rajasthan so far and that too patchily. An urban NREGA could potentially be used to build climate-resilient homes for the poor and, thereby, help them cope better with both extreme heat and flooding, two of the biggest effects of climate change in urban India. A suggestion was also voiced at a meeting in April by an office-bearer of the MGNREGA Mazdoor Union to use the NREGA to enhance green cover, to provide more shade. What is more, expanding the NREGA could both help tackle climate change and provide jobs, and thereby address India’s twin crises.

Pressuring the state to carry out effective adaptation measures at scale needs strong working class and other social movements. Sadly, climate change is becoming a political issue in India just when workers movements and the Left in general are much weaker than in their heyday. In their essay, Rajesh Nayak and Sharon Block correctly point out that workers end up bearing both the highest risks of climate change, through impacts on health and earnings, and the costs of adaptation. But it was disappointing that they provided only a few examples of workers’ or union responses, mostly from Canada and the US, where the social and political dynamics are very different from our own.

Over the last three years, catalysed by intense heatwaves, a range of unions, NGOs, and other collectives that organise or work with workers—construction, gig, and waste workers, street vendors, home-based workers, and so on—have intensified their engagement with climate change in India. They have been demanding that governments or municipal authorities provide protective shade, more water, cooling spaces, and toilets (which particularly matter to women working outdoors who drink less water as a consequence, potentially damaging their health).

In June last year, the National Disaster Management Authority issued an important advisory regarding health and safety protocols during heatwaves for informal workers in particular; it is a step forward but much remains for it to be followed widely.

In a meeting last year, an office-bearer of the Nirman Mazdoor Panchayat Sangam said construction work ought to be stopped between 11 am and 3 pm because most accidents occur on scaffolding during the hottest hours. The Amazon workers’ union has demanded that intense production or work targets be lowered during periods of extreme heat. Some organisations have also made the broader demand that heatwaves be notified a national disaster so that adaptation funds to help cope with their effects get released promptly and in much greater amounts than are being offered at present.

A connected, crucial area of adaptation to extreme heat is public health. In their essay, Nitya Khemka and Bhargav Krishna suggest a three-pronged approach: augmenting human capacities, including by adding climate change and health to existing curricula for nurses and doctors, and in-service training to recognise and treat symptoms of heat stress; embedding heat resilience within existing health programmes; and strengthening health infrastructure itself to cope with climate extremes. I would add that we need to fill our health personnel vacancies, and expand health infrastructure and access to be able to quickly treat victims of extreme heat.

Other than in some States like Tamil Nadu and Kerala, the health infrastructural reality across much of India and the Indo-Gangetic Plain in particular—an epicentre of extreme heat and humidity—is lagging decades behind a rapidly warming world. Many hospitals and health centres lack even the continuous electricity supply required to provide the ice and the air conditioning to quickly treat a person suffering from heatstroke. Clearly, we urgently need multisectoral interventions to respond adequately to a growing climate crisis.

Mitigation alongside adaptation

A few points in conclusion. First, greater financial support for adaptation (the subject of the final essay) is indeed much needed. But that requires political will; people’s lives and their quality of life need to matter more to political elites. Extreme heat and other manifestations of global warming affect those least responsible the most. Notions of justice that address this fact ought to lie at the core of how we develop climate adaptation capacities going forward.

Second, given the acceleration in warming, governments need to plan not just for the present but at least a decade ahead, which is largely not happening. Third, because scale is essential for adaptation, the state becomes a key actor. This has organisational implications for the climate movement; in order to exert greater pressure on the state to act swiftly, it needs to come together organisationally to be able to exert that pressure with more frequent success. Fourth, any just adaptation to or transition from climate change needs the climate movement, working class movement, women’s movement, and other social movements to ally and strengthen one another through a Red–Green framing of 21st century politics.

Finally, climate mitigation—primarily the rapid reduction of greenhouse gas emissions—is essential because the earth’s system does not negotiate. Its physics suggests that the planet will warm for as long as emissions continue. Global emissions need to reach zero or “net zero” for temperatures to stabilise and any further warming to stop.

Instead, carbon dioxide levels in the atmosphere are rising faster than ever and reached 431 parts per million last month, the highest in at least three million years. The urgency of the need to slow down and reverse direction has never been greater. Climate adaptation has its limits, and it would be monumentally foolhardy to assume that we can adapt to everything that a warmer planet will throw at us in the years to come.

Nagraj Adve is a member of Teachers Against the Climate Crisis and the author of Global Warming in India: Climate, Impacts, and Politics.

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