Heat is often intensified or amplified in cities, a phenomenon known as the urban heat island effect. Asphalt, concrete and similar materials absorb and retain significantly more heat than vegetation, so temperatures in urban areas are often 5°C hotter than surrounding suburbs or rural regions.
In neighbourhoods with fewer trees and green spaces, this heat often disproportionately affects older adults, low-income communities and some communities of colour.
A team at Nasa’s Goddard Institute for Space Studies (GISS) have used freely available satellite data to measure the effectiveness of architectural changes designed to reduce urban heat. These include replacing black tar and other dark-coloured roofing materials with bright, Sun-reflecting surfaces or “green roofs” full of plant cover.
Green roofs are designed to harness the cooling power of plants to lower the temperature in city spaces. The greenery may be extensive (shallow soil, low-maintenance...