Revisiting Abiotic Depletion Potential (ADP) to assess the risk of depletion of Magnesium

Since its conception by Guinnée & Heijungs (1995), the Abiotic Depletion Potential (ADP) has been revisited by many authors to propose improvements to assess more realistically the risk of depletion of many mineral resources to support decision-making. A lot of discussion has been made around the most meaningful definition of the natural stocks and authors have vacillated between considering a fixed stock or to treat natural stocks more like flows that need to be managed to meet human demands. This discussion needs to be carried with clear concepts and definitions and focusing on the aim of calculating ADP. Crust content is consensually the only reliable base for the calculation of natural stocks, since the concepts of resource and reserve imply in a dependence with geological knowledge and with technical, economical, and socio-political feasibility. Authors often adopt the same criteria to define the stocks of all the elements (e.g., same crust depth) and then the specificities of each element are neglected. In the circular economy context, efforts have been made to include anthropogenic stocks in the ADP calculation, but it is necessary to discuss what could be considered as an eventual recycling stock. This paper aims to revisit the ADP methodology and apply it focusing on magnesium, considering the singularities of magnesium sources and products.