Fifteen thousand kilometres from Patna, the sea off the coasts of Peru has been running hotter than it ought to. No one in India felt it happen and no one here caused it. Yet, on September 3, the World Meteorological Organization attached a probability to what it means for the rest of us—and that probability is the headline. The agency now puts the chance of El Niño lasting into February close to a certainty. It has issued these bulletins for half a century, but never before allowed itself that little hedging room. UN Secretary-General António Guterres said the event was “being supersized before our eyes”.
You can see why the forecasters are sure. The stretch of central Pacific that meteorologists watch most closely sat about 1.5°C above normal through late Spring; by mid-August some weekly readings had climbed to 2.6°C. More telling is what lies underneath. In places, water below the surface in July and early August ran 8°C warmer than it should, which is a way of saying the event has a great deal left to draw on. The WMO—which expects the crest around December, with consequences unspooling through the following year—has begun the biggest joint effort with national weather services it has ever attempted.
The dates are what India is most likely to misread. Warm oceans surrender heat to the air only gradually, which is why the year after a big El Niño usually turns out hotter than the year containing it; WMO officials have floated 2027 as a candidate for the warmest on record. Add a positive Indian Ocean Dipole, which forecasters expect to form, and our dangerous season is not the one behind us. It is the one that opens in March, about six months from now. The World Food Programme puts the additional people pushed into acute hunger by this event at roughly 5 crore.
Well before March, a woman breaking stones at a worksite in Gaya will find her body cannot dump heat quickly enough to finish the day’s quota, and nothing will suggest to her that the Pacific has anything to do with it. This is what a trans-boundary risk looks like: something that begins as physics in one hemisphere and ends as a missing wage and a missed school term in another. Peruvian fishermen named El Niño because the warm current showed up near Christmas. They named it. We inherit it.
What reaches her is not the heat we are used to talking about. A paper in the Journal of Geophysical Research: Atmospheres led by S K Saha of the Indian Institute of Tropical Meteorology finds the productivity we stand to lose to humid heat has crossed a threshold, climbing steeply rather than gradually, and that India is now the worst-affected place on Earth. The physiology is blunt. Sweat cools us only when it evaporates; fill the air with moisture and the mechanism stops. Long before anyone nears a survivability limit, the loss is economic. Work slows. Output drops. Where the wage is tied to the piece, the wage goes too.
Humid heat finds the people least able to withstand it, and the map of where it falls sits close to the map of where we are poorest. Around 49 crore Indians work informally, mostly in the open, with no enforceable claim to rest, water or shade. The slower harm does the greater damage: diets thin out, children stop turning up at school, money meant for food goes on medicine and cooling. Those happen to be the things the National Multidimensional Poverty Index (MPI) measures. It is also sitting directly in the path of poverty alleviation: states along the Gangetic humid-heat belt depend on outdoor manual work and have less access to cooling than anywhere else in India. The places that climbed out fastest are the places heat can most easily pull back down.
Something consequential happened on August 7, in the unglamorous shape of a written answer in the Lok Sabha. The Union home ministry confirmed that heatwaves, with lightning, now sit on the list of notified natural calamities governing the state and National Disaster Response Funds for 2026-31. Until then a state facing a lethal summer could declare it only on its own authority and spend no more than a tenth of its allocation. It can now reach the full response and mitigation corpus. The 16th Finance Commission had asked for precisely this, pointing to how much more often and more fiercely heatwaves now arrive. The National Disaster Management Authority had already built the scaffolding, writing guidelines and driving heat action plans out to states and cities; the missing piece was money bolted to the machinery.
But the reclassification matters more than the money. Heat here has been handled largely as a health problem, something hospitals soak up in May and the health ministry tallies afterwards. Calling it a disaster drags it into a different world, one of preparedness duties, response protocols, mitigation budgets and enforceable accountability.
It would be unfair to say our warning system ignores humidity. It has stopped doing so. The India Meteorological Department now runs a colour-coded heat index, issues impact-based warnings built around who is likely to be hurt rather than what the mercury reads, publishes heat-health advisories with the health ministry, and has introduced warm night alerts because damp coastal air robs the body of its overnight recovery. The forecasters have grasped the problem. The trouble sits one floor below them.
Money moves when a heatwave happens, and a heatwave, administratively speaking, is whatever the IMD declares one to be. That declaration turns on maximum temperature hitting 40°C inland, 37°C on the coast or 30°C in the hills, with a 4.5°C departure from normal. Every one of those readings is dry-bulb. The heat index shapes the advisory; it does not unlock the treasury.
Take one March day. Maharashtra’s Solapur logged 40°C at 53 percent humidity, a wet-bulb figure near 31.5°C. Jalgaon logged a far scarier 46.8°C at 29 percent humidity, which comes out lower on the wet-bulb scale. Solapur was the harder place to swing a pickaxe. Jalgaon got the declaration. Repeat that down a coastal belt and you have built a funding window that serves Rajasthan faithfully and misses Odisha just as faithfully.
The IITM paper carries a second finding that ought to rearrange how we do disaster policy: humid heat stress can be forecast with real confidence as much as six months out. Lay that against Geneva’s calendar and the arithmetic is awkwardly tidy. The event peaks around December. Our hot season starts in March. The lead time is no longer hypothetical; it is written on the wall.
A cyclone warning buys 72 hours, enough to move people and nowhere near enough to build anything. Six months is enough to budget, tender, train and legislate. In 2024 the Bangladesh Red Crescent triggered South Asia’s first early action protocol for heat, moving money already set aside to roughly 1.24 lakh people in Dhaka before the worst arrived, because somebody had settled the trigger in advance. India has the fund. What it lacks is the trigger.
Three things follow. Start by aligning the trigger with the forecast, the cheapest reform on offer because nothing new has to be invented: the 2026-31 guidelines have only just been drafted, and the definition of a qualifying heat event should take in wet-bulb and heat index thresholds alongside dry-bulb maximums, with a separate humid-heat category for coastal and Gangetic districts. Next, put the mitigation window to work on anticipation, building forecast-based financing around a December seasonal outlook released with the El Niño-Southern Oscillation update.
Third, close the legal gap: the Factories Act reaches indoor workplaces only, the Occupational Safety, Health and Working Conditions Code treats heat standards as guidance, and 49 crore informal workers are left without any thermal floor. Running beneath all three, we have to count better. Twenty certified heatstroke deaths this season against nearly 5,000 reported cases is not a figure anybody in the field finds credible.
Celeste Saulo, who runs the WMO, has said an El Niño this unusual calls for preparation to match. India has done the difficult institutional work of accepting that heat is a disaster and that disasters come with money. Our forecasters have separately done the difficult scientific work of learning to measure the kind of heat that kills.
The Pacific has now told us, more plainly than it ever has, roughly when the bill falls due. Whether any of that money reaches the woman in Gaya rests on something far more ordinary than atmospheric physics: whether two arms of the same state can be persuaded, in the six months they have, to read the same thermometer.
Sanjay K Srivastava | S Radhakrishnan Chair Professor, National Institute of Advanced Studies, Bengaluru; former Chief of Disaster Risk Reduction at UNESCAP
(Views are personal)