Nested circularity in food systems: A Nordic case study on connecting biomass, nutrient and energy flows from field scale to continent

Although a circular economy promotes economic and environmental benefits, knowledge gaps remain surrounding the application of these concepts to food systems. A better understanding of the connection between different flows of biomass and energy at different spatial scales is needed to facilitate effective transitions towards circular bioeconomies. This study provides a framework for assessing the circularity of food systems, which we exemplify by identifying key steps towards circularity for three contrasting farming regions in Finland. For each of the regions, we quantified the flows of biomass, nutrients and energy. We found large differences in circularity, depending on the chosen indicator. Most biomass and nutrient flows were related to livestock production, which implies that it plays a key role in circular food systems. Current livestock production was found to be connected to national and global food systems through the international feed trade. This trade generates imbalanced nutrient flows between regions and countries, resulting in excess accumulations of nutrients in regions with net imports. In terms of circularity in energy systems, we found that substantial amounts of energy could be produced from manure and plant-based biomasses without causing food-fuel competition in land use. We also observed that, the inclusion of human excreta would further improve recycling but this was significant only in the region with a high population density. Thus, in his study, we propose a concept of nested circularity in which nutrient, biomass and energy cycles are connected and closed across multiple spatial scales.