Comparison of individual food products may underestimate the underlying environmental impacts

Life cycle assessment (LCA) is commonly used to compare the environmental impacts of products with similar functions. Multifunctional processes are usually handled by allocation, permitting the analysis of results for a single product. In this study, instead of only comparing animal source foods with other alternatives, we compared dairy cattle, beef cattle, pork, cultured meat and tofu production at the system level in terms of climate change, land use and fossil resource scarcity impacts. Here, we first present the theoretical background to the system expansion method in attributional LCA. Then, the method is implemented by comparing dairy cattle, beef cattle, pork, cultured meat and tofu systems, which are standardised to include equal functions. Since animal production systems generate inedible by-products that find utility as feeds, fertilizers, and energy sources, we enhance comparability by including the alternative production of these by-products. The system-level results obtained through system expansion are then compared with economically allocated product results. The assessment revealed that the system-level results differed noticeably from the allocated product-level results, as the dairy system had the highest environmental impacts in all the assessed categories. This contradicts previous attributional assessments that primarily relied on allocation between by-products, particularly concerning beef derived from beef cattle. Although the system expansion method possesses certain limitations, we deem it appropriate for providing a novel perspective when comparing multifunctional systems. By maintaining the connections between products originating from the same production system, this assessment approach offers valuable insights into the diverse functionalities provided by different systems.