Embodied Carbon in Toronto's Urban Development
Urban Toronto | October 2, 2023
Dominic Mattman, BASc, MASc, P.Eng., LEED® AP | Associate
In Toronto's rapidly developing cityscape, where new buildings continuously rise, a silent yet significant environmental concern looms: the carbon emissions from these burgeoning developments. This issue has profound implications for the future of sustainable urban development. While operational carbon — such as the emissions from burning fossil fuels to heat and cool a building — often grabs headlines, a recent study by RJC Engineers and BDP Quadrangle delves deeper into the less-discussed topic of embodied carbon in residential structures, especially the carbon emitted during the construction phase of buildings. While operational carbon is becoming more manageable due to advancements in energy efficiency, the embodied carbon — often overlooked — is emerging as a significant contributor to the city's overall carbon footprint.
Dominic Mattman, an engineer at RJC and a lead author of the study, shed light on the findings in a recent interview with UrbanToronto. "Embodied carbon has become a much bigger focus in the past few years, especially as buildings become more energy-efficient [operationally]," Mattman told us.
The study analyzed four anonymized active residential projects in Toronto, finding that 60 to 77% of a building's total embodied carbon originates from the reinforced concrete used in construction. Measured against the Toronto Green Standard, three of the four studied projects met the TGS Tier 2 targets, with the fourth marginally exceeding them. None of the projects, however, achieved the more stringent TGS Tier 3 targets which the City is now looking for from new construction, indicating a need for a 20-30% reduction from the baseline to meet these ambitious goals. Mattman applauds the City's proactive approach to embodied carbon through TGS Tier 3, saying "It is great to see Toronto taking decisive steps to address this issue."
The construction of a building reflects the efforts of a team of architects, engineers, and other professionals working in harmony. "One of the biggest takeaways is that we need to collaborate earlier-on in projects.