Cooling Corridors: The Role of Green Infrastructure in Building Resilience to Extreme Heat

In partnership with Ryerson University’s Dr. Umberto Berardi, “Cooling Corridors: the Role of Green Infrastructure in Building Resilience to Extreme Heat” is the first report of its kind that quantifies the positive impact that the Greenbelt’s urban river valleys have on temperature. 

The evidence is clear that conserving and investing in trees and forests is a way to start building resilience for a future where heat events are more common and possibly more extreme.

Extreme heat is a human health risk that can be increased by urban development and climate change. Forested areas in communities like the Greenbelt’s urban river valleys and urban tree cover can provide cooling benefits and build resilience in Ontario’s Greater Golden Horseshoe communities to the increasing risks associated with extreme heat. 

Increasing tree cover can decrease the heat stress that people feel. The evidence is clear that conserving and investing in trees and forests is a way to start building resilience for a future where heat events are more common and possibly more extreme. This report lays out how to do this effectively, and can be used by communities as a guiding resource. 

High Level Findings:

• The Greenbelt’s urban river valleys are cooler than surrounding urban landscapes and can provide some relief during extreme heat events
• Increasing tree canopy just moderately in suburban neighbourhoods in Peel showed cooling benefits. The daily average temperature was up to 1.3^oC cooler across the study neighbourhoods after increasing tree canopy by 50%
• Cooling benefits continue to grow when additional trees were added to the landscape, decreasing daily average temperatures by up to 2^oC by increasing tree canopy by 80%.
• The cooling benefits of reforestation were greater than that of individual trees, leading to perceived temperature decreases as great as an 11^oC
• Even individual modelled trees showed an impressive impact on perceived temperature. It could feel 3^oC cooler in the evening under the shade of a tree

The cooling benefits of urban and near-urban greenspace will be critical during the summer months. For residents of Ontario without air conditioning and for whom a visit to a nearby mall or community centre to cool down is out of the question, time spent in greenspace may be the best means for staying active and cool.