Embodied carbon refers to the greenhouse gases emitted or removed throughout a building material’s life cycle such as the extraction, transportation, and manufacture of the product. Embodied carbon tracks carbon flows to and from the atmosphere and is typically reported as global warming potential (GWP). Embodied carbon values for individual products are reported in life cycle assessments (LCAs) and environmental product declarations (EPDs).
Industry wide EPDs or LCAs are widely available for most construction products. AWC EPDs can be found here.
Building level embodied carbon can be calculated by aggregating the materials and other activities used in building construction and refurbishment. Wood products tend to have low embodied carbon compared to other materials, so substituting wood for more embodied carbon-intensive materials can reduce the overall impacts of buildings.
Wood products also store carbon. Wood products are roughly 50% carbon by mass, meaning that the carbon absorbed from the atmosphere during tree growth remains locked in the building for as long as the material is in use. Stored carbon represents the carbon physically retained within a building material while it is in use. Stored carbon is typically reported in tC or tCO2.
Both embodied and stored carbon help us better understand the full climate impacts of building material choices.