Accounting for feed-food competition in environmental impact assessment: Towards a resource efficient food-system

This study demonstrates the effect of better accounting for feed-food competition in life cycle assessment (LCA) to derive mitigation strategies that contribute to efficiently feeding the growing world population. Economic allocation, commonly used in LCA, falls short in accounting for feed-food competition as it does not consider interlinkages in the food system. The authors hypothesise that an alternative food-based allocation better accounts for food-feed competition by assigning no environmental impact to feed products unfit for human consumption. To evaluate the impact of accounting for feed-food competition on LCA results, economic and food-based allocation were compared in an LCA of a novel egg production system that feeds only products unsuitable or undesired for human consumption. Using economic allocation, the global warming potential (GWP) of 1.30 kg CO2-eq, energy use (EU) of 10.49 MJ, land use (LU) of 2.90 m(2), and land use ratio (LUR) of 1.56 per kg egg of the case study farm were all lower than that of free range or organic eggs. Avoiding feed-food competition on this farm reduced the environmental impact per kg egg by 56-65% for GWP, 46-54% for EU, 35-48% for LU and 88% for LUR, compared to free-range laying hens fed a conventional diet. Accounting for feed-food competition with food-based allocation further reduced impacts per kg egg by 44% for GWP to 0.57 kg CO2-eq, 38% for EU to 4.05 MJ, 90% for LU to 2.59 m(2), and 83% for LUR to 1.29. This improved LCA better captures the complexity of the food system. (C) 2019 Elsevier Ltd. All rights reserved.