Biogenic carbon is carbon contained in biomass that is accumulated during plant growth. As a result, many natural materials store, or “sequester” atmospheric CO2 in the short term. In the Higg MSI, this is not subtracted from the Global Warming results but displayed as a separate inventory metric. This is consistent with many standards for communicating LCA results and is because there is no way of knowing that the carbon is sequestered for 100+ years in a cradle-to-gate LCA since the end of life is not included. Note that biogenic carbon is measured in kilograms of carbon, not CO2. One kilogram of biogenic carbon is equivalent to 3.67 kilograms of CO2 (based on stoichiometric ratios). So a material that has 0.39kg of biogenic carbon has incorporated the equivalent of (0.39kgC * 3.67kg CO2/kg C = ) 1.43kg of CO2.
The biogenic carbon amount for your custom material can be found on the downloadable spreadsheet.