This report was jointly prepared by contributors at TAF, Mantle, University of Toronto, and the City of Toronto and published in November 2022. The building sector is now considering the embodied carbon in the net zero objectives. This report shows the results of the first attempt to collect and compare embodied carbon results as calculated using whole building life cycle assessments (WBLCA) for Part-3 buildings in Ontario for 41 separate buildings. Methodology differences make high-quality comparisons between projects difficult. Embodied carbon intensities increase with building height due to increased materials per area and greater subsurface works. Buildings with timber structures seem to have lower embodied carbon (~16% lower). Including sequestration makes this difference significant (~59% lower). Any future policy should provide clear guidance for required life cycle phases, objects of assessment, material quantity data sources, and treatment of carbon sequestration. While there is some ‘noise’ in the results due to variations in methodology, scope of assessment, and tools used by the teams these results are an important first step in understanding embodied carbon results in the City of Toronto and other Ontario municipalities.

Keywords: Architecture/Engineering, Building Retrofits, Climate Change, Protocols/Standards, Embodied Carbon, Athena software, One Click LCA


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