During the summer of 2025, widespread heat waves overwhelmed power grids across North America, Europe, and the Middle East, prompting renewed interest in passive cooling technologies. As global warming intensifies, the demand for air conditioning places increasing strain on energy infrastructure. Radiative cooling, a millennia-old concept enhanced by modern materials science, offers a potential solution by scattering sunlight and dissipating heat without requiring additional energy.

Radiative cooling is a natural phenomenon where objects release heat into the environment. "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 radiate some of it back at night. This process explains why cars parked outside overnight often have condensation on their roofs, as the metal dissipates heat, cooling the surface below the ambient air temperature and leading to dew formation.

Humans have utilized radiative cooling for thousands of years. In desert regions of Iran, North Africa, and India, people historically manufactured ice by leaving pools of water exposed to clear desert skies overnight, capitalizing on the radiative cooling effect.

Modern research focuses on developing advanced paints, coatings, and textiles that maximize radiative cooling efficiency. These materials are designed to reflect sunlight across a broad spectrum and efficiently emit infrared radiation, allowing them to cool surfaces below the surrounding air temperature. The implications of widespread adoption of these materials are significant, potentially reducing the reliance on air conditioning and alleviating pressure on power grids, especially during peak demand periods.