Two studies in Science present new ceramic materials for passive cooling. This could potentially save a lot of energy.

Surfaces exposed to sunlight absorb solar heat and radiate it in the form of infrared radiation. When the heat emitted is greater than the heat absorbed, the surface cools. This is called passive cooling. To achieve this, you need materials that strongly reflect sunlight while emitting long-wave infrared light that can pass through the atmosphere without being reflected back.