New Greenbelt Foundation Report Reveals Critical Cooling Effect of Tree Canopies
Evidence Demonstrates Significant Temperature Reduction for Residents Near Urban River Valleys
This summer, heat will once again become a significant health risk in southern Ontario. Climate change and the urban heat island effect are increasing this risk. While we often hear about climate change causing extreme weather events like flooding, we take for granted the impact of heat itself. In 2018, 66 people died of heat-related illnesses in Montreal. According to CBC, that was 6.4 deaths per day per million inhabitants of the city.
Using climate modeling in two neighbourhoods in Peel Region, the report finds that increasing the number of mature trees could lower average daily temperatures by 2 °C and at times it could feel as much as 11°C cooler.
As a new report commissioned by Greenbelt Foundation explains, investing in natural assets like tree canopies is an important way to create more heat-resilient communities. The report, written by Ryerson University’s Dr. Umberto Berardi, examines how forested urban river valleys, park systems and residential tree canopies provide measurable cooling benefits to the region.
“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. Using climate modeling in two neighbourhoods in Peel Region, the report finds that increasing the number of mature trees could lower average daily temperatures by 2 oC and at times it could feel as much as 11 oC cooler. These cooling benefits extend beyond the direct shade of trees as well. The cooling benefit of forested areas was detected up to 150-250 m downwind where nearby residents received these benefits.
“With this report we wanted to ask – exactly how much are our urban river valleys helping keep communities cool and if we had more trees during heatwaves would people feel more comfortable and be healthier?” says Kathy Macpherson, Greenbelt Foundation VP of Research and Policy. “The answer is a resounding ‘yes.’ Increased tree cover can make it feel up to 11 oC cooler on a given day. This tells us that further investments in urban forests could have significant impact on human health and well-being.”
The evidence is clear that conserving and investing in trees and urban forests is an important way to build resilience for a future where heat events are more common and possibly more extreme. The scenario analyses illustrated in this report could benefit new and existing initiatives, like Canada’s Two Billion Trees program, in gleaning how to use trees most effectively to reduce heat stress for Canadians.
“This report provides evidence based on novel research developed with state-of-the-art technology on the role that the Greenbelt’s urban river valleys play in providing localized cooling effects,” says Dr. Umberto Berardi, Associate Professor at Ryerson University. “My research group—as well as Ryerson University—has always been committed to working for urban innovation and we are proud to have contributed this research to present new investigations towards local possibilities that address the challenges faced by the climate crisis”.
The cooling benefits of urban and near-urban greenspace will be critical this summer as Ontarians stay closer to home. For residents 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, cool and socially distant.
About The Greenbelt Foundation:
The Greenbelt Foundation is a charitable organization, solely dedicated to ensuring the Greenbelt remains permanent, protected and prosperous. We make the right investments in its interconnected natural, agricultural and economic systems, to ensure a working, thriving Greenbelt for all. Ontario's Greenbelt is the world's largest, with over 2 million acres of farmland, forests, wetlands and rivers working together to provide clean air, fresh water, and a reliable local food source.
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