Note on biogenic carbon
If you have wood products in your project, you will likely have to deal with the issue of biogenic carbon. Biogenic carbon refers to carbon that is “produced in natural processes by living organisms but not fossilized or derived from fossil resources” [11]. The process of extracting carbon dioxide from the atmosphere and storing it in a long-term form is known as carbon sequestration. In the building industry, this most commonly occurs in wood products. Other biogenic construction materials may include bamboo, straw, and cork. Sequestered carbon can be reported as a negative carbon “emission.”
Since wood is a product of removing carbon from the atmosphere, there is a perceived environmental beneft in using wood products. However, the question of how to quantify the impact of biogenic carbon is a complex and contentious issue, involving topics such as carbon neutrality, sustainable forestry certifcation, carbon accounting of everything in a forest including soil, and biomass burning.
For practical purposes in your LCA, you have two options for reporting biogenic carbon (at this time):
• Option 1: Ignore potential benefts of carbon sequestration. This is a conservative approach.
• Option 2: Include potential benefts of carbon sequestration.
If you chose Option 2, you should follow these additional guidelines (at this time):
• Report biogenic carbon emissions from each life cycle module for the three classifcations of biogenic carbon per ISO 21930 (2017) [11].
• Report the sequestration credit as a separate negative value (not added to the positive emissions values).
• If your biogenic material is wood, report the status of forest certifcation.
Carbon Leadership Forum - Life Cycle Assessment of Buildings: A Practice Guide