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Future of Heatwaves in South Asia

Future is not known. But some futures are far more unknown than others. Perhaps future of heatwaves in South Asia is one such futures. We know the future will see more frequent, more heated, and longer duration heatwaves in South Asia (world over) we do not know at what rate this acceleration will take place, and how many more ways this acceleration will impact life and livelihoods in South Asia.

For the past few months, HOISA has been critically observing what makes heatwaves in South Asia different, how it is prone to more such events, and the attempt to judge a heat wave index for South Asia. The recent discussion that took place on 6th June 2023, particularly looked at the Future of Heatwaves in South Asia in a world that is 1.5 to 2C warmer. We collectively looked at the various models that predict how heat waves will shape in the near future, the existing challenges, the work that is being currently done in India and the region, and what lies ahead of us.

To look into the future, we must understand how climate change is impacting the weather systems in South Asia. The IPCC AR6 2021 report predicts that as global temp increases, we will witness an increase in frequency and intensity of extreme temperatures that would occur once in 10 years in a climate without human influence. We already have a sense that with the rising greenhouse emissions, the temperature regimes will shift in a way that we will experience hot weather more frequently and severely, as compared to cold weather.

A study by the World weather Attribution initiative in 2022 particularly looks at comparing models of how the climate would behave in a world with no human influence with the actual observations, in order to deduce the possible futures. The heatwaves of 2022 that occurred in Northern India and South-Eastern Pakistan is an important heatwave to study.

In 2022, unusually high temperatures for a longer period in March and April were observed which caused major damage to wheat crop production. What was a one in a 100 years event, is today 30 times more likely with the already 1.2°C warmer world that we are living in. Calculated through hazard attribution, this will additionally increase 8 times in a 2C warmer world. Studies also show that regions with high humidity and high temperatures will particularly be high-risk areas, as we see that heat index (a combination of temperature and humidity) increasing by at least 2 degrees with 30 times more likelihood of such events in India and Bangladesh. This can and will be deadly.

In another recently published paper on Heat Waves over India in 1.5 to 2C warmer worlds, it was found that in such climates, we may not see a substantial increase in the highest temperature but the duration and the areal extent of the heatwaves will increase multi fold in certain regions of India. That is, more areas will be heated for longer duration in coming years in India. This study used various methodologies, and models from multiple countries, and used a large database of previous extreme events to design a framework for the prediction of heat waves in future.

It was found that the frequency of heat waves and severe heat waves will increase greatly, with new zones experiencing these phenomena which they previously didn’t. The probability of heat event days is increasing. We see a sharp increase in heat event days in June and July when it’s monsoon in India. The combination of temperature and humidity is particularly a matter of concern and therefore we see the use of real feel or heat wave index coming up. The probability ratio of heat waves lasting for more than 9 days will increase 10 to 20 times in certain regions. And we do not know if the gap between two heatwaves will be shorter or longer in the years to come. The joint frequencies of the longest duration and large area events could be 3x in 1.5C and 5x in 2C. And lastly, the model also looked at a few extreme weather events in the recent past in the region and looked at how its magnitude would increase in the warmer world that we are expecting. We observe a duration increase in these events, with heat waves lasting more than 40 days, there is an aerial increase in the area affected, and the emergence of new heat zones with minimal increase in the highest temperature.

AIDMI’s work on heatwave shows that the affected population numbers are increasing in each community, the diversity of affected population is increasing in terms of socio economic background and occupational context, and the measures taken by the community members on their own out-number almost all other public measures at individual and community level.

All of these results point at an immediate short-term, mid-term and long-term action strategy to cope with the various compounding effects of heatwaves in the region. There is already an immense amount of collective work that is underway by various agencies—such as the NDMA in India – in South Asia. Making National guidelines for preparedness, action plans, deducing plans for prevention and management of heat waves action, developing a national framework on heatwave preparedness and mitigation, coordination between several ministries, workshops for capacity building of stakeholders, scientific know-how is being strengthened on various fronts, developing impact-based early warning system are being formalized, Heat Actions Plans are being made at city and state level, there is a National action plan on heat-related illness and much more is coming up.  A lot can be learned from this list by other countries on bilateral South-South exchange.

In India, we are already witnessing the outcomes of these efforts. The mortality rate has drastically reduced in the past few years. Over 17 heat waves-prone states have prepared heat wave action plans and 14 states have also prepared their own action plans. Various departments, not all, are in sync with each other and there is an enhanced awareness of anticipatory actions among policymakers and the insurance sector is increasing.

We are also observing similar efforts of various degrees in South Asia. In Pakistan, an anticipatory response fund by the Start network is conducting training in preparedness and cooling, Cooling action plans by the Government are underway, and frontline workers are being trained by Pakistan Disaster Management Authority (PDMA) and Pakistan Red Cross Society (PRCS). In Bangladesh, a Chief Heat Officer has been appointed in Dhaka, Bangladesh, Heat Action Plans are underway in several municipalities and other pilot projects are being carried out.

But while this work is being carried out, it is important to carefully observe the issues and challenges that policymakers are facing today. Firstly, heat waves affect differently to different groups that may be defined by age, economics, and urban or rural location. Secondly, there are scientific gaps in measuring the local thresholds, and interplay of other meteorological parameters - velocity, humidity, and standard definition within different ecological zones. Thirdly, addressing deaths and damage needs more nuanced consideration in South Asia. Measuring the value of the loss and damage by heat waves is extremely difficult as it has a compounding effect on multiple sectors. Though a good start is done since Climate and Development Knowledge Network (CDKN) work in South Asia, it needs a relook for better impact. Reading into the multiple causes of death and thereby formalizing it into data is also very challenging. AIDMI calls it the “intersectionality of heatwave deaths” in its work on heatwaves.

As a way forward, we must observe heat waves better and study how they are linked to forest fires, drought, and other calamities that often get combined with it. We need to develop a loss and damage framework for South Asia that is more context-specific. Data collection and analysis for evidence-based policy and implementation of long-term mitigation is required by authorities in South Asia. Strong academic and implementing agency partnerships with robust early warning systems can greatly help in responding to heatwaves in the region. We must continue increasing the capacity of stakeholders and formulate stronger risk transfer mechanisms not only by the authorities or private sector alone but by tri-partite inclusion of civil society and solidarity organisations. While we have been successful in reducing the mortality rate caused by heat waves, we have to do better to also look into other heat-induced illnesses latent and evident in South Asia. As the predictions show, the boundaries between hot days and heat waves are increasing - how do we tackle that? And when a rain shower or cyclone makes a brief appearance in between. This calls for constant, ongoing anticipation of how the situation is evolving. And most importantly, we must think of long-term action plans, as short-term measures something that is manageable, but there must be a long-term framework that is implemented nationally in each country to ensure that we adapt to this human-induced climatic phenomenon that will affect over 2 billion people in coming years, worldwide and the largest number of them will be in or from South Asia.


Contributions from: Kunal Satyarthi, Krishna AchutaRao, Maryam Zachariah, Mihir Bhatt and Khayal Trivedi

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