Climate Change and You is a fortnightly newsletter written by Bibek Bhattacharya and Sayantan Bera. Subscribe to the newsletter to get it directly in your inbox.
Dear reader,
As I write this newsletter in Delhi, the world outside is burning. With a daytime high of 42 degrees Celsius, the very air feels baked. The noon-time sun is so harsh that the UV Index is up to 11 (where the skin burns in 10 minutes and human eyes can be severely damaged). Conditions are not just unbearable; sometimes they feel unlivable.
India is no stranger to crushing heatwaves, but the climate crisis is making summer heatwaves far more intense and deadly. The Delhi-based climate research consultancy Climate Trends published a briefing a few days ago, based on available research, to show why this is the case.
It cites a 2020 India Meteorological Department (IMD) study showing that, between 1961-2020, the frequency of heatwaves increased by 0.1 days per decade in the country's core heatwave zone (CHZ). This includes all the north, central, western and eastern Indian states, as well as parts of Maharashtra and coastal Andhra Pradesh.
The same study also found that the total duration of heatwaves in the CHZ has increased by 0.44 days per decade, while the maximum duration has also increased by 0.55 days per decade. Combined with the fact that average nighttime temperatures across the country have risen by about 0.21 degrees Celsius between 2010 and 2024, and the average humidity has increased by 4% between 2020 and 2024, the fact that we’re facing intense heatwaves every year is no surprise.
Meanwhile, a new study from UC Berkeley’s India Energy and Climate Center says that India needs to improve the energy efficiency of air conditioners. The study states that, over the next decade, as India becomes hotter, about 130-150 million ACs will be sold. This will drive peak power demand to 120 GW by 2030 and 180 GW by 2035, which is 30% higher than India’s projected national peak demand. Improving energy efficiency will help India avoid the power shortages we’re seeing in northern India and save consumers up to ₹2.5 trillion.
STATE OF THE CLIMATE
A global health emergency
The World Health Organization (WHO) was recently called upon to declare the climate crisis a global health emergency. This was the conclusion of the WHO-convened pan-European commission on climate and health—an independent body—which said that climate change poses a global health threat.
The exact term the WHO uses to declare a global health emergency is “public health emergency of international concern” (PHEIC). This is the highest emergency category and was last used during the covid pandemic. Such a declaration carries legal weight because member countries would then be obligated to cooperate among themselves to address the crisis on a war footing.
The commission said that severe climate change is driving a dangerous increase in the international spread of vector-borne diseases such as dengue. Moreover, extreme climate directly affects global health by exacerbating heat stress, food shortages and air pollution. The commission has proposed 17 recommendations across four domains: climate change as a threat to health security, transforming health systems, scaling up local action, and reforming entrenched economic and financial systems that drive climate change.
THE NEWS IN BRIEF
-I wrote a long feature last week on how climate change is making trekking and climbing in the Himalaya very dangerous. Speaking to trek operators and mountaineers, what emerged is that Himalayan seasons have been completely disrupted by rising heat, and that the only way to prepare for high-altitude climbing and trekking expeditions in these new circumstances is to plan for cloudbursts, landslides, and blizzards. This is the new normal.
-Mint carried an explainer on how heatwaves work and how to take care of oneself during one. A very useful reckoner.
-The summer football World Cup, to be played in the US, Mexico and Canada, has emerged as a health risk for players and audiences, because most matches will be played in very hot and humid conditions.
CLIMATE CHANGE TRACKER
How heat stress affects Indian labour
India’s tryst with extreme heat is pushing the needle into the red when it comes to health and productivity. Nowhere is this truer than in agriculture and manufacturing, especially given India’s dangerously rising wet-bulb globe temperature (WBGT). This is a measure of high heat plus high humidity, which can result in fatalities.
An April 2024 report from the International Labour Organization (ILO), titled Ensuring health and safety of work in a changing climate found that 70% of the global workforce of about 3.4 billion people is exposed to excessive heat at work every year. The pan-European commission on climate and health said that 640 billion labour hours had been lost worldwide in 2024, due to extreme heat. The In an already hot and humid country like India, where an overwhelming number of workers are in the informal sector, working as agricultural labour or in construction, the danger is multiplying.
A recent study on heat stress on labour in south India, published in the journal Nature, found that of the 1,560 outdoor workers surveyed, all worked in conditions where the critical WBGT threshold was repeatedly exceeded. Heat stress could result in a loss of 80 million full-time jobs in agriculture and construction by 2030. This becomes even more critical because much of Indian labour work in conditions that can only be termed inhumane.
A 2026 survey of textile and garment sector workers, undertaken in Tamil Nadu and Delhi-NCR, found, among other things, that 36.5% of workers could only access unclean drinking water on the factory floor. 78.3% of workers said it was difficult to get permission to use the toilet, while 80% said the air was too hot and stuffy, with no ventilation. It is clear that while climate stress is posing a threat to labour health, the existing conditions of workers in the country are exacerbating the danger.
KNOW YOUR JARGON
Heat Dome
One of the defining features of the current heat in north India is just how still the air is, and how relentless the heat's sheer intensity is. As it turns out, this is because much of the region has been stuck under a massive heat dome this past week. A heat dome is exactly what it sounds like—an oppressive high-pressure atmospheric system that pushes down hot air towards the land surface and then traps it there for a prolonged period of time.
The only way for a heat dome to dissipate is for storm systems to move in, which stabilize conditions by sweeping the hot air away. As things stand, there is no forecast of any such thing happening for the next one week to ten days. India isn’t alone in suffering from this phenomenon: Britain and large parts of Europe are currently under heat domes.
PRIME NUMBER
141
That is the number of countries that recently voted in the UN to uphold a 2025 advisory opinion by the International Court of Justice that countries have a legal obligation to stop climate change. In it, the ICJ stated that countries must prevent harm to the climate system, and that if they failed to do so, they would have to pay compensation.
Earlier this month, a resolution brought in the UN by the Pacific island nation of Vanuatu affirming the ICJ ruling was voted upon by member states, despite the US trying to scuttle the vote. It was passed 141-8, with the US among the 8 countries voting against it. Twenty-eight countries abstained, including India. Although not legally binding, the vote sets a precedent, and the ICJ ruling may yet prove crucial to moving the needle on climate action in a meaningful way.
And that’s it from me this week, dear reader. Sayantan will be back in a fortnight with the next edition of Climate Change & You.