Reducing biodiversity impacts of agricultural production while maintaining food supply – a modelling study of the Swiss food system

Summary

Agri-food systems are essential for food security, yet they are major drivers of biodiversity loss through land conversion, intensification, and related emissions, threatening long-term stability of food production. To design food systems that sustain biodiversity while ensuring food provision, biodiversity impacts must be systematically assessed at food system level. This study integrates a food system model (SOLm) with biodiversity characterization factors from the global life cycle impact assessment method (GLAM), enabling consistent biodiversity impact assessment across multiple drivers. The analysis focuses on four drivers of biodiversity loss—land use, eutrophication, acidification, and climate change—and evaluates contributions to biodiversity impacts across alternative production scenarios in Switzerland. Results show that all alternative scenarios reduce biodiversity impacts from domestic production. Scenarios aligning livestock populations with grassland availability and reducing feed-food competition achieved the most substantial reductions, driven by lower pressures from climate change, eutrophication, and acidification, while maintaining calorie and protein supply. Land-use impacts decreased less, particularly in organic systems, due to lower yields, risking externalization of biodiversity impacts through increased imports. Impacts from imports were dominated by products such as coffee and cocoa, which exert substantial external pressures, although biodiversity impacts per unit area were lower for organic production than conventional. Thus, lower yields in organic systems necessitate additional measures, such as reducing feed-food competition and food loss and waste, to improve biodiversity outcomes. Coupling production-side measures with food supply shifts and food loss and waste reductions can lower biodiversity impacts without compromising food availability. The proposed model for integrating biodiversity indicators with food system modelling provides a globally applicable framework for analysing trade-offs between food supply and biodiversity. However, due to lack of data, global biodiversity indicators lack relevant aspects, e.g. related to soil microbiome or eco-toxicity from plant protection means. Assessing significance and potential bias from missing aspects is required to ensure balanced conclusions.