More than half the world’s population now lives in cities that are often much hotter than their rural surroundings. Roads, buildings and paved surfaces absorb and store heat during the day, then release it slowly after sunset. This is known as the urban heat island effect.
Discussions about why cities overheat tend to focus on buildings, which is understandable. As well as absorbing solar radiation, residential and office buildings consume a lot of energy through lighting, heating and air conditioning. They release waste heat, and shape the flow of air through surrounding streets.
