Using green infrastructure to relieve urban heat-related stress

Our Land Regeneration and Urban Greenspace team is currently examining how effective different types and sizes of greenspace are at helping to cool the local environment

News from Forest Research: October 2012

Trees and greenspace in an urban environmentCities are warmer than their surrounding countryside by an average of 2ºC per 24-hour period and by as much as 10ºC at night. With heat-related stress accounting for some 1,100 premature deaths per year in the UK, the thermal comfort and health of city dwellers in a changing climate is of growing concern. Forest Research’s Land Regeneration and Urban Greenspace team is currently examining how effective different types and sizes of greenspace are at helping to cool the local environment.

In contrast to the countryside, cities lack vegetation and permeable surfaces, and urban building materials have a tendency to trap the sun’s energy. These factors combine to cause localised warming, a phenomenon known as the Urban Heat Island (UHI).

Trees and the wider green infrastructure can provide significant reductions in local air temperatures and collectively can be very effective at combating the UHI. Using green infrastructure to relieve urban heat-related stress (cont.)

It is hoped that our work will help deliver UHI mitigation strategies and provide additional UK evidence on the value of trees and greenspaces in the built environment.

As part of this research we are working with colleagues skilled in geographic information systems to map the cooling influence of greenspaces across Greater London. Initial results from this work indicate that on average over 99% of Greater London is cooled by greenspaces, while for Inner London the average is 88%. Collectively, this work helps identify those areas where new greenspaces could help combat the UHI. The work is expected to conclude in Spring 2013.

For more information contact Kieron Doick or see our web page on the role of urban trees in regulating heat and UV exposure.