Climate Change and You: India's summer heatwaves have begun and the heat may soon affect food security

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,

The great Indian summer heatwave is here, and it is already a scorching one. Right now, I’m in Kolkata, writing this newsletter even as the political climate heats up in the city. And this is happening in the midst of intense heat in Kolkata, where a potentially deadly combination of high heat and high humidity has turned working outdoors into a severe stress test for the human body.

In this, Kolkata is not alone, with large parts of the country in the grip of an intense heatwave. On Saturday, the India Meteorological Department (IMD) published an advisory, stating that northern and central India will experience a heatwave through the week, while heat and humidity will dominate eastern and coastal India. In a follow-up advisory issued on Sunday, IMD stated that maximum temperatures across the country were currently between 1.5-5.1 degrees Celsius above normal.

As a result of the heatwave, India’s peak power demand too hit an all-time high of 252.07 GW on Friday, surpassing the previous peak set in May 2024. On Saturday, 95 of the world’s hottest cities were located in India. Even though the heatwave is expected to subside towards the end of this week with thunderstorms and rain expected across northern and eastern India, worse might be in store later in May and June

STATE OF THE CLIMATE

Super El Niño cometh

The reason for not expecting any respite lies in the fact that El Niño conditions are developing in the Pacific Ocean, and this is going to supercharge heat around the world. El Niño and La Niña are two natural climate phenomena over the Pacific that take turns in heating and cooling the climate respectively. Climate scientists have forecast that the current La Niña conditions are waning and El Niño conditions are setting in, a process that will be complete by later this year.

During El Niño, the surface temperatures of the central and eastern tropical Pacific Ocean rise, setting off cascading effects across the globe. This not only leads to greater heat, but also greater aridity. When it comes to India, El Niño conditions will result in more heatwaves and a lower-than-normal monsoon this year. IMD has already forecast as much.

But scientists are saying that this will not be a regular El Niño episode, because what is evolving in the Pacific is the rare condition of the ‘super’ El Niño. This occurs when sea surface temperatures warm by over 2 degrees Celsius, and in extreme cases, over 2.5 degrees Celsius. Such conditions have developed just a handful of times since 1950, with the strongest El Niño recorded so far being in 2015-16, when sea surface temperatures did breach the 2.5 degrees mark.

The apprehension among climate scientists is that the heat generated by such strong El Niño conditions will build on the amount of heat already trapped by record-high levels of carbon dioxide (CO2) emissions in the atmosphere. This combination is highly likely to push the average global temperature by 1.7-2 degrees Celsius above pre-industrial levels, and thus unleash climate catastrophes across the world. India, with a high baseline temperature, will be especially vulnerable to droughts, unpredictable rainfall, acute heat stress, and superstorms.

THE NEWS IN BRIEF

-A recent article in The Guardian explores how exposure to large amounts of toxic chemicals, in conjunction with climate change impacts, is contributing to a global drop in fertility.

-On Monday, India submitted its revised climate mitigation goals or NDCs under the Paris Agreement, and highlighted the need for greater financial resources to meet these targets.

-An excellent analysis in Lounge shows how rising heat is disrupting the business of Indian women street vendors, making them ill, eroding their incomes, and pushing them into a debt trap.

CLIMATE CHANGE TRACKER

Himalayan snow and ice at an all-time low

I have been tracking the effect of climate change on the Himalaya in this newsletter and in my stories for Mint. But even the knowledge of the Himalaya’s vulnerability to rising temperatures doesn’t prepare one for the scale of changes that are occurring across the range. Case in point: A report released on 21 April by the International Centre for Integrated Mountain Development (Icimod) has found that snow cover in the Hindu Kush Himalaya (HKH) region is the lowest it has been in 20 years, 27.8% below normal. The HKH Snow Update 2026 report also states that this marks the fourth consecutive year of decline.

HKH is the geographical name for high mountain Asia, comprising 11 major ranges including the Himalaya, Karakoram, Kun Lun Shan and the Hindu Kush. Extending some 3,500km across 8 countries from Afghanistan to Myanmar, the HKH is the origin of 10 major river systems (including the Ganga, Brahmaputra, Yangtse, Mekong and Indus). These river basins provide water to nearly 2 billion people and have sustained entire civilizations since time immemorial. The majority of this water comes from snow and glacier-melt in the HKH. Only, it seems that this ‘water tower of Asia’ is slowly collapsing.

Icimod is a regional scientific and research body based in Nepal, set up by the 8 HKH countries (including India), and the organization tracks seasonal variability in the mountain regions, apart from longer reports on the state of the region.

KNOW YOUR JARGON

Amoc

One of the major Earth systems that are close to a collapse due to climate change is the Amoc or the Atlantic Meridional Overturning Circulation, a major ocean current in the Atlantic Ocean that helps regulate the planet’s temperature. The Amoc brings warm tropical waters to the Arctic and sub-Arctic regions, where they cool and sink, forming a deeper return current that carries cool water back to the tropics.

While its immediate impact is that of regulating temperatures in Europe, the Amoc also plays a big role in keeping tropical rainfall belts stable and sustains the Amazon rainforest. Recent studies have found that greater heat in the Arctic is actually slowing down the Amoc as warm tropical waters are not getting cooled, and some have worried that the giant current may be close to shutting down. A new study, published in the journal Science Advances, has found that there is a 50% chance of the Amoc slowing down over this century, which would inevitably lead to a tipping point and a subsequent shutdown of the current.

If the Amoc were to shut down, it would have global consequences. Europe would alternately face severe winter cold and summer droughts, tropical rainfall patterns would change, imperiling food security for millions of people, sea levels would rise, and it might even lead to a die-back of the Amazon rainforest. The latter would throw the world into another catastrophic warming loop.

PRIME NUMBER

250

A major new joint report from the UN’s World Meteorological Organization (WMO) and the Food and Agriculture Organization (FAO) warns that due to rising heat, farmers in already heat-stressed countries like India will soon find it impossible to work for up to 250 days a year. The report, titled Extreme Heat and Agriculture, states that world food systems are under increasing stress due to a variety of factors caused by climate change, including livestock stress, repeated heatwaves affecting crop yields, and extreme heat preventing farmers from working. Taken together, this is threatening the livelihoods of over a billion people worldwide.

The report makes use of various case studies from around the world, including that of rice cultivation in India and how it is affected by rising humid heat (wet bulb heat). “Based on an ensemble of high-resolution climate change simulations…extremes of wet bulb temperature in South Asia are likely to approach and, in some locations, exceed critical thresholds for worker safety by the late twenty-first century under high-emission scenarios. The most intense risk from future heatwaves is concentrated around densely populated agricultural regions of the Ganges and Indus River basins. Without further mitigation, heatwaves will become a major threat to Indian agricultural workers and rice production,” the report states. A good 70% of India’s calorific intake comes from rice.

VIDEO OF THE MONTH

The only island of meaning in the galaxy

Are we alone in the Universe? This is a question that has haunted humanity for a long while. While rumours of alien contact are rife, we have not had any reason to believe, so far, that intelligent life exists anywhere in our Milky Way galaxy, let alone in the wider Universe. I recently came across a video by the English physicist Brian Cox, talking about the Great Filter hypothesis.

The hypothesis posits that there are inevitable technological and biological ‘filters’ that hold back the rise and propagation of planetary civilizations like ours. This is the reason why intelligent life is extremely rare, and that there is a possibility that only one such civilization exists per galaxy at any given time.

Unsettling as that thought is, Cox ends the video by saying something really beautiful. “Let’s assume that we are the only civilization currently in the Milky Way galaxy, perhaps the only civilization there will ever be. That means the Earth is the only island of meaning in a sea of 400 billion suns. And if we destroy this [planet], we might destroy meaning in a galaxy forever.” Right now, that Great Filter for humanity seems to be climate change.

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.