The greenest cities should be, well, green. Leafy walls and roofs could help people turn down the air conditioning on hot days, saving huge amounts of energy. It could lower temperatures by up to 11 °C, depending on the city.
Eleftheria Alexandri and Phil Jones at the Welsh School of Architecture at the University of Cardiff, UK, used computer models to compare the impact of “greening” buildings in nine cities, including temperate London in the UK, humid Mumbai in India, and tropical Brasília in Brazil.
Using temperature data from each city’s warmest month, they found that the air would…
