A spatially explicit approach to assessing commodity-driven fertilizer use and its impact on biodiversity

Global demand for food, including rising consumption of meat and dairy products, is increasing pressure on the environment and natural resources, often in locations distant from points of consumption. To identify and quantify consumer driven impacts and the components of the supply chain where sustainability interventions will be most effective, spatially explicit consumption-linked indicators that encompass environmental risks are required. Large amounts of phosphorus fertilizers are used in Brazilian soybean cultivation, which potentially cause eutrophication and impact freshwater species. We use a sub-national trade model to develop a spatially explicit approach for assessing commodity-driven phosphorus fertilizer use and its potential impact on biodiversity linked to four key consumers. The use of phosphorus for embedded consumption per capita of Brazilian soybean in China, the EU, the UK, and Sweden are estimated at municipal level and combined with metrics that influence losses of phosphorus to create a normalised relative risk index. The relative risk index is presented in geospatial visualisations to explore geographical patterns of risk to freshwater biodiversity and make the link between consumer and producer countries less obscure. The results indicate high phosphorus-linked species risk in municipalities within Mato Grosso, Rio Grande do Sul, Paraná, and Goiás. Sweden and the UK generate the highest relative risk and the geographical patterns of risk differ between the investigated consuming countries, showing that smaller countries can have relatively large impacts at a spatially explicit scale. In the Amazon biome, risk of nutrient losses and biodiversity are relatively high, creating concerns as soybean production is expanding into the area. The results and methodological approach can contribute to understanding of accountability, agency, and increased transparency for the governance of global supply chains, necessary for enabling transformations towards sustainable food systems.