Emission Omissions: Carbon accounting gaps in the built environment

The report argues that current LCAs often produce variable results due to undisclosed assumptions and omissions, particularly regarding biogenic carbon in wood products. It emphasizes that building energy efficiency and longevity are the primary drivers of decarbonization, as operational emissions typically dominate the total life-cycle impact. The authors recommend greater transparency in LCA data, the development of a regionalized national life-cycle inventory for Canada, and a balanced policy approach that incentivizes decarbonization across all material manufacturing sectors rather than favoring one material over others.

• Life-cycle assessments (LCAs) of building materials exhibit high variability and a lack of standardization, often failing to disclose the assumptions and uncertainties that significantly influence their results.
• Operational emissions typically dominate the total life-cycle GHG impact of buildings, often accounting for an average of 80% of emissions, which suggests that energy efficiency and building longevity should be prioritized over material substitution.
• Many LCAs exaggerate the relative importance of embodied emissions by ignoring operational stage emissions and other building systems such as site preparation, heating, and ventilation.
• The assumption of carbon neutrality for wood products is a major source of uncertainty; sensitivity analyses show that accounting for soil carbon loss, lower regeneration rates, and the conversion of natural forests can significantly increase the reported embodied emissions of wood buildings.
• Regional variability significantly impacts embodied emissions, particularly for steel, where sourcing from electric arc furnace (EAF) mills using recycled feedstock can reduce emissions by a factor of two to four compared to basic oxygen furnace (BOF) mills or imports from China.
• The carbonation of concrete, where CO2 is reabsorbed over time, is generally too small to significantly impact overall life-cycle emissions, likely reducing embodied emissions by only 3% to 6% under current practices.
• Decarbonizing the built environment requires a combination of short-term measures (such as clinker substitution and alternative fuels in cement production) and long-term transformative technologies like carbon capture and storage (CCS) and hydrogen utilization in steelmaking.

APA

Stiebert, S., Echeverría, D., Gass, P., & Kitson, L. (2019). Emission Omissions: Carbon accounting gaps in the built environment. International Institute for Sustainable Development. https://www.iisd.org/sites/default/files/publications/emission-omissions-en.pdf

Chicago

Stiebert, Seton, Daniella Echeverría, Philip Gass, and Lucy Kitson. Emission Omissions: Carbon accounting gaps in the built environment. International Institute for Sustainable Development, 2019. https://www.iisd.org/sites/default/files/publications/emission-omissions-en.pdf.

Wikipedia

{{cite report |last1=Stiebert |first1=Seton |last2=Echeverría |first2=Daniella |last3=Gass |first3=Philip |last4=Kitson |first4=Lucy |title=Emission Omissions: Carbon accounting gaps in the built environment |publisher=International Institute for Sustainable Development |date=April 2019 |url=https://www.iisd.org/sites/default/files/publications/emission-omissions-en.pdf |access-date=23 October 2026 |via=Climate Insights Directory}}

BibTeX

@techreport{stiebert2019emission, author = {Stiebert, Seton and Echeverría, Daniella and Gass, Philip and Kitson, Lucy}, title = {{Emission Omissions: Carbon accounting gaps in the built environment}}, institution = {International Institute for Sustainable Development}, year = {2019}, month = apr, url = {https://www.iisd.org/sites/default/files/publications/emission-omissions-en.pdf}, urldate = {2026-10-23}, note = {Indexed by Climate Insights Directory} }