During the summer of 2025, widespread heat waves strained power grids across North America, Europe, and the Middle East, highlighting the growing need for innovative cooling solutions. As global warming intensifies, the demand for air conditioning increases, placing further stress on energy infrastructure. However, a technology rooted in millennia-old practices, enhanced by 21st-century advancements, offers a potential solution: radiative cooling.

Radiative cooling involves the use of paints, coatings, and textiles designed to scatter sunlight and dissipate heat without requiring additional energy. This process is a fundamental aspect of the natural world. "Radiative cooling is universal—it exists everywhere in our daily life," said Qiaoqiang Gan, a professor of materials science and applied physics at King Abdullah University of Science and Technology in Saudi Arabia. Gan explained that objects absorb heat from the sun during the day and release some of it back into the atmosphere at night. This phenomenon is evident in the condensation that forms on cars parked outdoors overnight, as their metal roofs dissipate heat, cooling the surfaces below the ambient air temperature.

Humans have been leveraging radiative cooling for thousands of years. In desert regions of Iran, North Africa, and India, people historically produced ice by leaving pools of water exposed to the clear night skies, allowing radiative cooling to freeze the water.

Modern advancements are now refining this natural process. Researchers are developing specialized paints and coatings that maximize the scattering of sunlight and the emission of heat, leading to more effective cooling. These materials hold the potential to reduce the reliance on traditional air conditioning systems, thereby lowering energy consumption and mitigating strain on power grids. The development and deployment of these materials could have significant implications for urban planning, building design, and energy policy, especially in regions susceptible to extreme heat.