Heat is a familiar foe in my part of the world. Often touted as a ‘silent disaster’ because of the difficulty in recording and attributing heat-related impacts and deaths, the lived experience of heat in South Asia is anything but silent. It is audible in the whirring of water coolers and air conditioners across the subcontinent in summer and an increasingly warmer spring; it is echoed in the bellows of the hot, dust-laden loo winds that blow across Pakistan and north India in April and May; it glints in the excessive sweat as dry heat moves into oppressive humidity of the monsoon. In South Asia, the drumbeat of heat is already loud, and it is getting louder.

In this essay I make three connected points about living with and adapting to heat in a climate changed and deeply unequal world. First, despite the lived reality of high heat in the subcontinent, the nature of the hazard is projected to change, sharply testing interconnected food-livelihoods-energy-water systems. Second, exposure to heat is unequal, and is overlaid on existing matrices of differential vulnerability. Third, current measures to cope with and adapt to heat remain uneven and potentially insufficient.

The changing nature of heat

The latest IPCC Working Group II Sixth Assessment Report on Impacts, Adaptation and Vulnerability makes it clear that if greenhouse gas emissions are not rapidly eliminated, increasing heat and humidity will create conditions that test human tolerance.

Extreme heat is not an unknown, future risk in South Asia, it is here and now, with a clear fingerprint visible in all climate projections. In 2015, the region experienced the fifth deadliest heatwave recorded globally which led to approximately 3,500 heat-related deaths across Pakistan and India. Without concerted action to mitigate greenhouse gas emissions that are causing temperature rise, and adaptation to deal with heat risks, the future is only going to get worse.

Recent projections state that South Asia, in particular, will see increasing heat and humidity, with direct impacts on national GDP and peoples’ livelihoods, human and animal health, and food and water security. Currently, wet-bulb temperatures^[1] in India rarely exceed 31°C, with most of the country experiencing maximum wet-bulb temperatures of 25 to 30°C. Under high emissions scenarios like RCP8.5^[2], cities like Lucknow and Patna in India are expected to reach wet-bulb temperatures of 35°C by the end of the century, while Bhubaneswar, Chennai, Mumbai, Indore, and Ahmedabad are at risk of reaching wet-bulb temperatures of 32 to 34°C.

In South Asia, intense heatwaves of longer durations and higher frequency are projected over India and Pakistan. At the city-level, these projections become very significant: at 2°C global warming, Kolkata, on an average, will experience heat equivalent to the 2015 record heatwave annually; Karachi will experience such heat about once every 3.6 years. More worryingly, heatwaves are expected to come earlier in the season and stay longer, with tangible impacts on crop yields and overall agricultural productivity.

The year 2022 was a glimpse of this changing nature of heat. India and Pakistan experienced a devastating set of heatwaves as early as March, with reported impacts on wheat yields; flowering and fruiting in horticultural crops such as mangoes; antecedent impacts on farm incomes; and approximately 95 deaths across India and Pakistan. A study found that the 2022 heatwaves were made 30 times more likely due to anthropogenic climate change, clearly linking global greenhouse gas emissions in driving extreme heat in South Asia. In the media cacophony that followed the 2022 heatwaves, international media tended to focus on how the heatwaves could disrupt global food chains, already strained by the Russia-Ukraine war; and whether countries like India are investing in adaptation adequately. This media discourse placed lesser emphasis on the real and fast-approaching limits to adaptation such heat places on vulnerable people and how unmet global climate finance goals are exacerbating adaptation inequities in certain places.

The unequal experience of heat mirrors existing matrices of differential vulnerability

Being a climate change researcher in an unequally climate changed world means having to constantly be confronted by the reality of living in one of the most exposed and vulnerable regions in the world. Current maps that overlay heat projections with their potential impacts repeatedly identify South Asia as a region most at risk.

Source: IPCC Working Group II Technical Summary Figure 7.8 Projected additional annual deaths attributable to climate change in 2030 and 2050 compared to 1961–1990 (WHO, 2014).

Risk, of course, is a composite term, denoting the incidence of a hazard (extreme heat), exposure to the hazard (based specific conditions such as whether you work outdoors or not), and vulnerability (your susceptibility to harm due to heat, based on factors such as age, gender, location, or ethnicity). When swathes of countries are denoted ‘high risk’, it is crucial to ask, who is at risk and who is not?

The disproportionate impacts of extreme heat are symptomatic of underlying structural vulnerabilities that ensure that certain social groups, engaged in certain livelihoods, and of certain ages and genders, are most vulnerable. Critically, drivers of vulnerability intersect with one another to exacerbate overall vulnerability. Thus, outdoor wage labourers who are lactating women are significantly more vulnerable to extreme heat than their male counterparts. Informal settlements in cities cruelly concentrate vulnerability (and therefore risk); since their dense population, lack of green spaces, and poorly ventilated houses make them heat hotspots or urban heat islands.

Despite this recognition of the importance of vulnerability in mediating heat risk, “a meta-analysis of 27 studies of heat risk in South Asia found that only vulnerabilities based on age and sex and cause of death had been explored in most studies, which could potentially be due to insufficient data on socio-economic and other characteristics”. The analysis also found that only two studies analysed “differences due to other individual or intra-population characteristics such as socio-economic status, education, occupation, housing, or level of urbanisation”. A recent review of 37 Heat Action Plans across India also echoed this inadequate and incomplete focus on examining differential vulnerability: from the 37 plans, only two reported explicitly conducting vulnerability assessments to drive their risk management.

Jesse Ribot, in his foundational text, Vulnerability Does Not Fall from the Sky writes, “The damages associated with climate events result more from conditions on the ground than from climate variability or change. Climate events or trends are transformed into differentiated outcomes via social structure”. Work from Nausheen Anwar et al. in Pakistan takes this call head on by arguing that proposing “a way forward to think about Karachi’s changing weather and the onset of chronic heat exposure in terms of ‘zones of vulnerability’. Such zones are crucial to consider not only due to their higher vulnerability to detrimental effects of heat exposure, but also because risks associated with rising temperatures are likely to make them into nodes that reveal, deepen and sediment pre-existing socio-spatial inequalities within cities like Karachi.”

It is imperative that as we consolidate a nuanced understanding of heat risk, we take care to correct past silences on differential vulnerability and pay equal attention to the mediating role of social structure on defining who is most vulnerable, and who is most at risk.

The insufficiency of current adaptation to heat

Growing acknowledgement of heat risk has led to a slew of heat action plans (HAP) across South Asia. India proudly highlights its frontrunner status, with Ahmedabad city developing the regions first HAP in 2013. Several cities, states, and even countries have followed, demonstrating an impressive range and complexity in the extreme heat preparedness and management actions. Adaptation to heat seems to be underway and national governments are quick to highlight decreasing heat-related mortality as a signal of effective adaptation. But is this borne out in the evidence?

A recent global review, assessed more than 1600 academic papers on adaptation to heat and found that that while adaptation to heat is underway, it is somewhat fragmented, reactive, and unequal. Most planned adaptation actions, especially in cities, was reported from the Global North while countries in the Global South reported more autonomous, often reactive, adaptations, especially in agriculture and allied sectors.

In India, there are a range of strategies and policies being implemented to adapt to heat: infrastructural solutions like better ventilated buildings or changing construction practices and materials drawing from vernacular architectural practices; awareness building solutions such as heat advisories and public campaigns on heat dos and don’ts; ecosystem-based solutions like green roofs, urban parks, and water harvesting for protective irrigation; and planning and institutional solutions such as urban zoning mandates for green cover, shifting outdoor work timings, and investing in agile health institutions that factor in increasing heat risk in staffing and capacity plans. Market-based solutions are also entering the mix, such as Arsht-Rock’s Extreme Heat Employment Insurance initiative which is a parametric insurance scheme to help women recover wages lost due to climate-driven extreme heat events. While promising in intent, concerns over post-project premium payments, especially for those with the least capacity to, remain.

Painting rooftops with white reflective paint is an effective yet relatively expensive option for informal settlements in Indian cities. Picture: Chandni Singh, Bhopal, 2023.

Taken together, these heat management initiatives, impressive in their spread tend to commit the most basic of adaptation fallacies. First, the insufficiency fallacy, where they do not adequately engage with projected heat risk, thus reacting to today’s heat rather than preparing for tomorrow’s heat. Second, the unfit-for-purpose fallacy, where they overlay a remarkable set of solutions on an overstretched and poorly capacitated bureaucracy, undermining the implementation and effectiveness of heat action plans.

The deeper danger these ‘solutions’ mask is that of heat management interventions potentially replicating existing vulnerability and inequality. It is known that adaptation solutions are not equally available to all. For example, active cooling through air conditioners is expensive and requires stable electricity. Nature-based cooling interventions, such as through urban parks, can intensify ‘green apartheid’ since they tend to be disproportionality available to wealthier residents, relegating low-income groups to heat hotspots. Well-intentioned labour laws mandating no outdoor work during extreme heat can reduce exposure to heat, but in the absence of alternate work, can penalise those depend on daily wages for sustenance.

Conclusion

South Asia is at an unenviable crossroads when it comes to extreme heat. On the one hand, countries in the region are deeply exposed to climate risks, with extreme temperatures and high humidity expected to test time-tested strategies to cope with heat. On the other hand, it is a region that is making incremental steps towards planning for and managing heat, with lessons for similarly exposed, deeply vulnerable countries and peoples.

In this essay I have argued that while these incremental adaptation actions are promising, South Asia is inadequately and unevenly adapting to its hotter future. In particular, the heat adaptation pathways (i.e., bundles of sequential heat management solutions) we are embarking upon hold the danger of reproducing past inequalities along the fissures of gender, caste, and livelihoods.

With intense media attention and policy acknowledgement, heat is no longer a silent disaster, but it is important to know examine whose solutions are being heard and which voices are being drowned. Going forward, funders, planners and implementers working on heat risk management need to carefully keep climate justice considerations at the centre when understanding how heat impacts are disproportionate; how abilities and resources to cool homes and move out of heat-exposed jobs and neighbourhoods are unequal; and how well-intended adaptation interventions can also have unequal outcomes. Recognising how histories of disenfranchisement, marginalisation, and exclusion, shape present-day vulnerability to heat and unequal capacities to adapt to it, should be the starting point of every solution we propose.

Acknowledgements: This piece draws on years of conversations with Amir Bazaz and Aromar Revi on exploring differential climate change risks and the unequal capacities to adapt that characterise climate change action in India. Long-term research synthesis initiatives I’ve been part of for the IPCC’s Sixth Assessment Cycle and the Global Adaptation Mapping Initiative (GAMI) have also informed this piece. More recently, my thinking on adapting to extreme heat has been enriched by engaging with Lea Berrang-Ford, Kamal Kishore, Rajashree Kotharkar, Sheetal Patil, Nihal Ranjit, Prathijna Poonacha, and Ketaki Ghoge. Thank you to Archita Suryanarayanan and Namrata Nirmal from the IIHS Word Lab for their editorial support and to Nausheen Anwar for inviting me to write this piece, and for her own incisive scholarship at the intersection of heat and informality in South Asian cities. Gratitude to the many heat-exposed people I have spoken to over the years across rural and urban India, who are living and adapting on the frontlines of this climate changed world.

Chandni Singh is a Senior Research Consultant at the School of Environment and Sustainability, Indian Institute for Human Settlements, Bangalore INDIA. She is working at the interface of climate change and development in rural and urban geographies within the global South.