A Commodity Supply Mix for More Regionalized Life Cycle Assessments

Supply chain information
is invaluable to further regionalize product
life cycle assessments (LCAs), but detailed information linking production
and consumption centers is not always available. We introduce the
commodity supply mix (CSM) defined as the trade-volume-weighted average
representing the combined geographic areas for the production of a
commodity exported to a given market with the goal of (1) enhancing
the relevance of inventory and impact regionalization and (2) allocating
these impacts to specific markets. We apply the CSM to the Brazilian
soybean supply chain mapped by Trase to obtain the mix of ecoregions
and river basins linked to domestic consumption and exports to China,
EU, France, and the rest of the world, before quantifying damage to
biodiversity, and water scarcity footprints. The EU had the lowest
potential biodiversity damage but the largest water scarcity footprint
following respective sourcing patterns in 12 ecoregions and 18 river
basins. These results differed from the average impact scores obtained
from Brazilian soybean production information alone. The CSM can be
derived at different scales (subnationally, internationally) using
existing supply chain information and constitutes an additional step
toward greater regionalization in LCAs, particularly for impacts with
greater spatial variability such as biodiversity and water scarcity.