27-degree nights: the bill for heat that won't go away

Heat is now an economic problem: 22% of older people at risk at 1.5 degrees

Global warming is no longer a laboratory debate: it's a bill. This week, a study in The Lancet Planetary Health put numbers on what many residents of Valencia and Barcelona are already suffering in their own nights. With an increase of just 1.5 degrees, 22% of people over 60 will be exposed to heat stress hazards. The figure is serious, but the economic debate has barely begun.

The study that puts a price on heat

The research, published in The Lancet Planetary Health, concludes that sweltering heat will be far more frequent and widespread than previously thought. For older people, the problem is physiological: the body loses its ability to regulate its internal temperature. The economic translation is immediate: more hospital admissions, more medication, more dependency. And a health system already brushing its limits.

The study's numbers are stark: with 1.5 degrees of warming, 22% of the world's population over 60 will live in areas at risk from extreme heat. This is not a distant projection: it is a scenario already taking shape, as this summer's records in the Mediterranean show.

Nights that never drop below 27 degrees

In Valencia, for example, overnight lows have gone weeks without dropping below 27 degrees, with highs feeling close to 34. Those who remember the 1990s point out that reaching 30 degrees used to be rare. In Barcelona, torrid nights have become the norm. Some attribute this to age, to the thermal inertia of asphalt and to decades of concrete releasing stored-up heat.

That urban heat island effect is real, but it doesn't explain everything. The last century and a half has recorded a rise in temperatures, more pronounced in cities. The swimming pool at four in the afternoon in the 1980s is not the same as today's, however hard it may be to admit.

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Of course, there are those who don't believe the projections. The "catastrophes have always been predicted" argument echoes through any climate debate, and the economics of forecasting is full of curves that failed. But the heat of these nights is not a projection: it is measured on a thermometer that doesn't play politics.

The question left on the table is how much it will cost to adapt cities, healthcare and housing to a climate that has already changed. Or perhaps the answer is simpler: even the most convinced sceptic sleeps worse at 27 degrees.