Construction practices and policies need to change if Canada is to meaningfully reduce GHGs from the building sector, a new report finds. Emission Omissions: Carbon accounting gaps in the built environment, a new peer-reviewed study conducted by the International Institute for Sustainable Development (IISD), examines Life-cycle Assessments (LCA) – the primary tool used by industry and researchers to account for GHGs and other impacts of building products at each phase of their “cradle-to-grave” lifespan (i.e., production, use, end of life).
The study confirmed that Life-cycle Assessment (LCA) is the best-available tool for evaluating GHG performance of alternative building products and designs, but found that current LCAs have limitations that may misdirect efforts to reduce GHGs from the built environment – one of Canada’s largest sources of emissions.
The researchers identified the need to correct poor assumptions about embodied carbon in concrete, wood and steel building products. For example, the research found that the land use impacts from mining and quarrying for concrete need to be better understood. However, it singled out forestry products for urgent attention because current LCAs ignore emissions from “biogenic carbon.” The study found that these omissions could represent up to 72% of the life-cycle emissions of wood products. When these emissions are taken into account, concrete’s embodied carbon footprint could be up to 6% less intensive than that of wood products.