Even Small Green Spaces Can Help Cities Stay Cool

Researchers surveyed Russell Square, London and other green spaces for the study. (Credit: Forestry Commission)

A study of urban green spaces shows that the size, composition and arrangement of green spaces all contribute to their effectiveness at cooling cities, counteracting the urban heat island effect. A release from Forest Research, the Forest Commission’s research agency in England, shows that if green space is at least 0.5 hectares in size, it will have significant cooling effects on urban environs.

Conducting their study on various London parks, researchers investigated greenspaces from 0.2 to 12.1 hectares in size. Only the 0.5-hectare size and larger seemed to cause a meaningful decrease in air temperatures.

In addition to the size of the green space, the composition of the green space also affected how much of an impact it had: The more grass coverage in the green space, the greater its cooling effect. And the more trees a green space had, the more the cooling effect was shown to extend to areas around the space.

Researchers estimate that a network of green spaces 3 to 5 hectares in size approximately 100 to 150 meters apart would likely be sufficient for cooling a city of London’s size.

Top image: Researchers surveyed Russell Square, London and other green spaces for the study. (Credit: Forestry Commission)