New Nature Sustainability study warns billions face cooling poverty in heatwaves

When a heatwave hits and temperatures spike, most of us automatically look for ways to cool down. A fan whirs away, chilled water is within reach, and the curtains are pulled to block the late-afternoon glare.

Those everyday measures can take the edge off a brutal day. Yet for billions of people, none of those basic comforts are available.

In many regions, households live in buildings that hold on to heat, with patchy electricity and little dependable access to safe water.

Large numbers of people also have no choice but to work outside beneath relentless sunshine. With climate change pushing temperatures ever higher, these realities are fuelling a widening public health emergency.

A recent paper in Nature Sustainability has attempted to quantify the scale of the problem.

Billions face cooling poverty

The researchers calculate that over two billion people are living in what they describe as “cooling poverty” - exposure to hazardous heat without secure, safe, or affordable ways to keep cool.

Their analysis comes as parts of South Asia continue to endure extraordinary heat above 45°C (113°F).

That level of heat forces urgent questions: who is most at risk, and what practical protections can be put in place?

Air conditioners are not enough

It may seem obvious to conclude that the answer is simply to provide air conditioners. The study authors argue that this assumption misses the point.

“Cooling poverty and what we call systemic cooling poverty refers to conditions in which individuals are prevented from attaining thermal safety, not simply because they lack an air conditioner,” said Giacomo Falchetta, a scientist at the Euro-Mediterranean Center on Climate Change.

Even as a straightforward fix, mass distribution would fail: air conditioners draw huge amounts of electricity and can overwhelm fragile power systems.

“We absolutely cannot air-condition our way out of this crisis,” added climate activist Harjeet Singh of the Satat Sampada Climate Foundation.

Poverty makes heat worse

If the issue is not merely the absence of a device, what is driving the harm? The study argues that heat rarely acts alone.

Instead, its effects intensify when it intersects with poverty, substandard housing, and under-resourced public services.

Aziza Mohamed, a professor of human geography and urban studies at Cairo University, says this should reshape how we interpret hot weather.

“The real danger does not come from climate alone,” she said.

“It comes from the interaction between heat, poverty, housing quality, weak health services and the absence of suitable infrastructure.”

Homes that trap the heat

One major risk factor is the home itself. Poor-quality housing does not shield people from heat; it can turn into a heat store.

Singh points out that millions of low-income urban residents live beneath tin or asbestos roofs - materials that can drive indoor temperatures up to five degrees hotter than the air outdoors.

And when electricity supply is unreliable and water quality is unsafe, even basics such as drinking enough and keeping cool become far more difficult.

A second, closely linked risk is healthcare. Once extreme heat pushes the body beyond its limits, getting rapid treatment can be the difference between life and death.

Where clinics are few, hard to reach, or overstretched, a heat-related illness that could be easily managed by a doctor may become fatal.

Work that offers no shade

A third danger comes from livelihoods. Farmers, construction workers, and street vendors can spend hour after hour in direct sun, with no option to retreat into a cooler indoor space.

Their bodies are further strained because much of the exposure is to humid heat, which prevents sweat from cooling the skin effectively.

These risks are not shared equally. Women, children, older people, minorities, and the poorest households are typically hit hardest.

They are also the groups most likely to be living in inadequate housing, excluded from healthcare and information, and left without spare resources to protect themselves.

Two regions on the edge

Two world regions emerge as particularly exposed, though for different reasons. In South Asia, a blend of humid heat, vast outdoor workforces, and weak policy responses makes conditions especially perilous.

Singh describes the region as “at the absolute frontlines of the climate crisis,” confronting “a lethal combination of geographic vulnerability and systemic economic inequality.”

In Sub-Saharan Africa, the route to extreme risk is different: a widespread lack of basic infrastructure.

Falchetta cautions that even where temperatures are lower, “the near-total absence of protective infrastructure means any intensification of heat would be catastrophic.”

Egypt shows another path

Egypt illustrates that severe heat does not always mean the highest risk.

Even though most of Egypt’s population faces hazardous heat and humidity, the country recorded comparatively low cooling poverty, which the study links to stronger housing, infrastructure, and public services.

The heat still arrives, but where communities have the means to respond, the damage can be limited.

Cheap fixes that actually help

There is also evidence that low-cost measures can make a real difference. White roof paint can bring indoor temperatures down by several degrees, while straw and clay can provide inexpensive insulation.

Tree planting, restoring ponds and parks, and setting up public cooling shelters with free drinking water can help entire neighbourhoods stay cooler - without relying on a single air conditioner.

To make these approaches effective, governments must support them with legislation and funding, rather than rhetoric. Even so, the study makes clear that these measures only extend the window for action.

“You cannot adapt your way out of extreme heat endlessly. There are limits to extreme heat adaptation,” added Chandni Singh, of the Indian Institute for Human Settlements.