In summer, high temperatures can make city living a pain. Why is it so much hotter in urban areas than in the countryside, and what are Swiss cities doing to tackle these “heat islands”? Globally, one out of every two people lives in a city. In densely populated Switzerland, the figure is 73%. In summer, these urban centres can become furnaces, with temperatures several degrees higher than in the rural areas around them; in Zurich, Bern, and Geneva, the gap between the city and areas outside of it can be up to 7°C on a summer’s night. The problem is known as the “urban heat island” effect, a phenomenon that has increased as the climate has warmed, especially in the densely populated towns and cities of Switzerland’s central plateau region. Why is it warmer in urban areas? For one thing, the many concrete and asphalt surfaces absorb solar radiation and heat up the surrounding air. A lack of green spaces is also a factor, as is limited air circulation due to high-density...
