If you're reading this while the blinds are drawn against yet another heat wave and wondering whether it’s finally time to buy an air conditioner, you’re far from alone. At the end of June, as temperatures climbed well above 40 degrees Celsius across Europe, shoppers in France literally forced their way into stores to snatch up portable fans and ACs before they sold out.

Such scenes are likely to become more common. As the planet warms, the demand for cooling is rising worldwide. The International Energy Agency (IEA) predicts two-thirds of households could own an AC by 2050. Politicians are turning ACs into a weapon in their broader culture wars. Far-right figure Marine Le Pen pledged to roll out air-conditioning across France if her party comes to power, while the British Conservatives vowed to overturn net-zero rules that restrict AC installation in new builds. On the left, the argument runs that air-conditioning would mainly benefit the rich and not those who need it most.

Europe is warming faster than any other continent, and countries that once had relatively mild summers are now experiencing increasingly frequent and intense heat waves. Research by Nicole Miranda at the University of Oxford suggests that countries such as the UK, Switzerland, Norway, and Finland could see some of the largest relative increases in heat exposure and cooling demand if global warming reaches 2 degrees C above preindustrial levels.

But simply adding more air-conditioning is not necessarily the answer—at least not in its current form. Because air-conditioning is built on a paradox: The machines that keep us cool are also heating the planet. The electricity they consume already accounts for roughly 3 percent of global greenhouse gas emissions, slightly more than the aviation industry.

This impasse has led some scientists and companies back to the drawing board. Paul Motzki at Saarland University is focusing on nickel-titanium that snaps back to its original shape, absorbing heat from its surroundings and generating what is known as an elastocaloric cooling effect. The team is currently testing the prototype in the lab but expects to deploy it in new buildings within the next few years.