The Indian capital recorded a temperature of 43.5°C yesterday, a figure that, when combined with humidity, pushed the heat index beyond survivable limits for unprotected labour. This is not a weather event. This is a signal of systemic breakdown.
As a climate scientist, I am tired of saying this: the planet is warming. But the data from Delhi is a stark reminder that the warming is not uniform. It is amplified in regions already under stress. The heatwave gripping northern India is part of a pattern: the breakdown of the jet stream, the weakening of the Indian monsoon, and the relentless accumulation of greenhouse gases.
Let’s be precise. The 43.5°C air temperature is bad enough. But the human body responds to wet-bulb temperature, which accounts for humidity. In Delhi, the wet-bulb temperature yesterday reached 35°C. Beyond 35°C, the body cannot cool itself through sweating. For those without air conditioning, death becomes a statistical certainty. This is not alarmism. This is physiology.
The British Met Office, in coordination with the IPCC, has been warning for decades that such events would become frequent. The latest Hadley Centre models show that by 2050, Delhi will experience wet-bulb temperatures above 35°C for at least 20 days per year. That is not a prediction. That is a projection based on current emissions trajectories.
The wider context is global instability. Heatwaves in India reduce agricultural output, stress water supplies, and trigger mass migration. The 2022 heatwave in Pakistan and India caused an estimated 90 billion hours of lost labour. That is not a weather statistic. That is an economic shockwave.
What can be done? The answer is not adaptation alone. Delhi’s poor cannot afford air conditioning. The grid cannot handle the load. The only stabilising force is a rapid phase-out of fossil fuels. The technology exists: solar, wind, storage. But the political will is missing.
We are treating a fever with paracetamol while the infection rages. Every degree of warming makes these events more intense. The 1.5°C target is not a political goal. It is a survival threshold. We are currently on track for 2.7°C. That is not a number. That is a death sentence for parts of the world.
I do not use hyperbole. I use data. The data says: act now, or the Earth’s thermostat will be reset to a state not seen since the Pliocene, when sea levels were 25 metres higher. Delhi is not an anomaly. It is a preview.
