Europe is on the verge of a fundamental reassessment of climate control principles, as rapidly rising temperatures and frequent heatwaves have exposed the critical vulnerability of both existing infrastructure and traditional cooling systems. In late June, temperatures in several regions of the continent exceeded 40 degrees Celsius, triggering a surge in demand for fans and portable air conditioners that instantly emptied store shelves. However, scaling up conventional technology carries severe environmental risks: cooling already accounts for about 3% of global greenhouse gas emissions, and widely used fluorinated refrigerant gases have a global warming potential thousands of times greater than carbon dioxide if leaked. In response, the European Union has begun phasing out these substances, pushing researchers and startups to actively develop innovative solutions that completely eliminate the need for chemical refrigerants.

At the forefront of this technological revolution are solid-state cooling systems, which rely on materials that can change their temperature in response to external physical forces, rather than the circulation of liquids and gases. At Saarland University in Germany, in collaboration with the Irish company Exergyn, elastocaloric cooling using nickel-titanium alloys is being successfully tested; these alloys cool down during cyclical stretching and relaxing, demonstrating the ability to lower indoor temperatures by 5–10 degrees. In parallel, other players are exploring alternative approaches: Canada's Mimic Systems is deploying thermoelectric heat pumps powered by electric current; Germany's Magnotherm is developing magnetocaloric systems for supermarkets; and the UK startup Barocal, which recently raised $10 million, is working with plastic crystals that release heat under pressure.

Despite their impressive potential, experts warn that new devices alone cannot solve the global overheating problem, especially given Europe's architectural specifics, where most buildings were historically designed to retain heat, and dense urban development promotes heat accumulation. Consequently, researchers and urban planners are increasingly advocating for a "cooling hierarchy," which prioritizes passive methods—such as using reflective materials, natural ventilation, and architectural shading—resorting to mechanical systems only as a last resort. As an example of large-scale infrastructure adaptation, Paris is actively expanding its district cooling network, which circulates cold water from the Seine River through underground pipes to air-condition major public buildings. This highlights the urgent need for comprehensive, coordinated urban planning to adapt to the new realities of a warming climate.