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We present a global-scale life cycle assessment of a major food commodity, farmed salmon. Specifically, we report the cumulative energy use, biotic resource use, and greenhouse gas, acidifying, and eutrophying emissions associated with producing farmed salmon in Norway, the UK, British Columbia (Canada), and Chile, as well as a production-weighted global average. We found marked differences in the nature and quantity of material/energy resource use and associated emissions per unit production across regions. This suggests significant scope for improved environmental performance in the industry as a whole. We identify key leverage points for improving performance, most notably the critical importance of least-environmental cost feed sourcing patterns and continued improvements in feed conversion efficiency. Overall, impacts were lowest for Norwegian production in most impact categories, and highest for UK farmed salmon. Our results are of direct relevance to industry, policy makers, eco-labeling programs, and consumers seeking to further sustainability objectives in salmon aquaculture.

Food systems—in particular, livestock production—are key drivers of environmental change. Here, we compare the contributions of the global livestock sector in 2000 with estimated contributions of this sector in 2050 to three important environmental concerns: climate change, reactive nitrogen mobilization, and appropriation of plant biomass at planetary scales. Because environmental sustainability ultimately requires that human activities as a whole respect critical thresholds in each of these domains, we quantify the extent to which current and future livestock production contributes to published estimates of sustainability thresholds at projected production levels and under several alternative endpoint scenarios intended to illustrate the potential range of impacts associated with dietary choice. We suggest that, by 2050, the livestock sector alone may either occupy the majority of, or significantly overshoot, recently published estimates of humanity’s “safe operating space” in each of these domains. In light of the magnitude of estimated impacts relative to these proposed (albeit uncertain) sustainability boundary conditions, we suggest that reining in growth of this sector should be prioritized in environmental governance.

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