Studying the Bentway’s Carbon Impact (with Ha/f Climate Design)

April 10, 2024

As The Bentway embarks on our next chapter and plans for future growth along the Gardiner Expressway, we want to better understand the impact of our physical spaces on the local environment. The Gardiner is a carbon-intensive structure built primarily of concrete, steel and asphalt, as are many of the roads and trails that surround it

To understand The Bentway’s environmental impact in this context, we’ve been asking ourselves some key questions: How big is the carbon footprint of The Bentway’s spaces? What strategies can be used to lessen greenhouse gas emissions resulting from the site’s construction? Which site materials and assemblies have the biggest impacts, and are there alternatives that can be explored? 

Working with subject matter experts Half Climate Design, we set out to uncover the “carbon intensity” of The Bentway Phase 1 site (between Strachan Ave and Fort York Blvd)., with an eye to the existing carbon footprint of the Gardner Expressway overhead.

Life Cycle Assessments (LCAs) are becoming standard practice in the construction industry, which is widely regarded as having massive environmental impacts. Embodied carbon emissions from the construction industry contribute approximately 10% of all global energy emissions, according to the Canada Green Building Council (CGBC). All carbon emissions from construction need to be accounted for and reduced for the sector to reach its climate change targets. In Canada, if we account for all building materials and construction, the sector contributes to almost 30% of our national carbon emissions.  As builders, programmers, and operators of public space, The Bentway is interested in how we can collectively and strategically reduce emissions in construction and reach Toronto’s ambitious climate targets outlined in TransformTO’s plan for 2040. 

To conduct this study, Half Climate Design looked at the type and amount of materials used in the Phase 1 construction, such as cement, timber, and planting soil. The study revealed that many of the assemblies used to construct The Bentway Phase 1 relied on carbon-intensive materials like concrete, and, although we have large planting areas that perform well, we are not achieving enough offsetting of the impact of the concrete through carbon sequestering. 

The study provides insight into where reductions in emissions and embodied carbon can be found in future phases of construction and supports The Bentway’s ongoing advocacy for the development of a climate adaptive and resilient public realm.  As The Bentway looks to expand into other spaces along the Gardiner Expressway in the future, we aim to increase the integration of bio-based materials in our construction, and preference the use of locally salvaged existing materials over the use of new carbon-intensive materials like concrete, brick, foam XPS products, and steel. 

For more information on the how The Bentway and Ha/f Climate Design are investigating carbon impacts, please contact us.

All visuals and renderings courtesy of Ha/f Climate Design.