While air conditioning provides temporary respite from the summer heat, it’s making the world warmer. Cooling houses, cars, and workplaces takes a lot of energy. AC and fans account for around 10% of the world’s electricity consumption and are huge drivers of emissions. Still, in the face of deadly record-high temperatures, many have to turn to their AC units to stay safe and keep cool.

To mitigate the coming AC boom, city planners and architects are implementing "passive cooling,” using building design and materials to control temperatures. Passive cooling isn’t just sustainable; it’s also cheaper and more widely accessible, making it a promising strategy for surviving the heat.

Why This Matters

Air conditioning, or fixed cooling, is common in Japan and the US (where 90% of houses have it), but has been relatively rare in other parts of the world. Now, as it gets hotter worldwide, that’s starting to change. In the UK, for example, just 1% of buildings have fixed cooling systems, but a recent report estimates that 20% will have them by 2035, and 50% by 2075. By 2050, AC use in the UK could triple, requiring additional electricity capacity equivalent to the US, EU, and Japan's current combined demand.

The burden of this AC boom will fall disproportionately on the Global South, which emits the least. In countries like India, Indonesia, and Brazil, climate change causes blistering heat, but only fractions of the population can afford air conditioning. Hot weather claims 12,000 lives a year, which will only grow if climate change goes unmitigated. Keeping people cool is a matter of life or death. The World Health Organization calculates that by 2030, extreme heat could cause an additional 38,000 deaths annually.

Sustainable Ways Cool Down

There are many sustainable ways to beat the heat without cranking the AC, like:

• Opening a window: This simple solution is shockingly effective. A new study found that natural ventilation and shading alone can lower indoor temperatures by about 14 degrees Celsius and reduce the load on AC units by up to 80%. This strategy works the best in places with milder temperatures, like the Mediterranean or the Pacific Northwest.
• Designing buildings with passive cooling in mind: In North Africa and the Middle East, wind towers on the roofs of buildings allows wind to push fresh air indoors and let hot air escape. Shading devices, double-glazed windows, and water fountains can also mitigate heat passively.
• Planting "Green Corridors”: This is a form of natural infrastructure as lants provide shade, which prevents concrete from absorbing and radiating heat (AKA heat islands). In Medellin, Colombia, where urban planners installed streets lined with vegetation to keep pedestrians and cyclists shaded, the city’s average temperature lowered by 2 degrees Celsius.

Another way of keeping AC but making it more sustainable is to power it with renewables rather than fossil fuels. In Texas, wind and solar power met almost 40% of the state’s electricity needs last month when a heat wave made energy demand skyrocket.