Emission Omissions: Carbon accounting gaps in the built environment

This report by the International Institute for Sustainable Development (IISD) examines the limitations and uncertainties of life-cycle assessment (LCA) tools used to compare the greenhouse gas (GHG) emissions of concrete, steel, and wood in the built environment. It argues that current LCAs often lack transparency and omit critical data—particularly regarding biogenic carbon in wood—which can lead to misleading conclusions about the relative performance of building materials. The report concludes that prioritizing energy efficiency and building longevity offers greater mitigation potential than focusing on material substitution alone.

• Life-cycle assessments (LCAs) of building materials often produce inconsistent results because assumptions and uncertainties are frequently not fully disclosed, and sensitivity analyses to test these assumptions are rarely performed.
• Many LCA studies may overstate the importance of embodied emissions by ignoring or discounting operational stage emissions and other building systems, such as heating, ventilation, and site preparation.
• Regional factors significantly influence life-cycle emissions. For instance, steel from Canadian electric arc furnace (EAF) mills can have embodied emissions two to four times lower than steel from basic oxygen furnace (BOF) mills or imports from China. Additionally, wood end-of-life emissions can be up to 10 times higher in landfills without methane recovery compared to those with recovery.
• The accounting of biogenic carbon in wood products is a major source of uncertainty. Many LCAs assume carbon neutrality by ignoring soil disturbance, carbon losses from converting old-growth forests, and the fact that as little as 15% of a tree's carbon may be sequestered in the final product.
• When testing different forest management scenarios—such as a 90% silvicultural success rate or soil carbon loss—cradle-to-gate emissions for wood buildings increased by 5% to 72% compared to a carbon-neutral baseline, suggesting wood could have higher embodied emissions than concrete.
• For energy-efficient buildings with long service lives, the impact of material choice is negligible compared to operational efficiency, meaning embodied emission reductions should not be prioritized over energy efficiency.

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/system/files/publications/emission-omissions-es.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/system/files/publications/emission-omissions-es.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/system/files/publications/emission-omissions-es.pdf |access-date=17 August 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/system/files/publications/emission-omissions-es.pdf}, urldate = {2026-08-17}, note = {Indexed by Climate Insights Directory} }