The anthropogenic stock extended abiotic depletion potential (AADP) as a new parameterisation to model the depletion of abiotic resources

Raw material availability is a cause of concern for many industrial sectors. When addressing resource consumption in life cycle assessment (LCA), current characterisation models for depletion of abiotic resources provide characterisation factors based on (surplus) energy, exergy, or extraction–reserve ratios. However, all indicators presently available share a shortcoming as they neglect the fact that large amounts of raw materials can be stored in material cycles within the technosphere. These “anthropogenic stocks” represent a significant source and can change the material availability significantly. With new characterisation factors, resource consumption in LCA will be assessed by taking into account anthropogenic material stocks in addition to the lithospheric stocks. With these characterisation factors, the scarcity of resources should be reflected more realistically.

This study introduces new characterisation factors—the anthropogenic stock extended abiotic depletion potentials—for the impact category depletion of abiotic resources. The underlying characterisation model is based on the conventional model but substitutes ultimate reserves by resources and adds anthropogenic material stocks to the lithospheric stocks.

A fictional life cycle inventory, consisting of 1 kg of several metals, was evaluated using different characterisation factors for depletion of abiotic resources. Within this analysis it is revealed that materials with relatively large anthropogenic stocks, e.g. antimony and mercury, contribute comparatively less to abiotic depletion when using the new characterisation factors. Within a normalized comparison of characterisation factors, the impact of anthropogenic stock results in relative differences between −45% and +65%, indicating that anthropogenic stocks are significant.

With the new parameterisation of the model, depletion of abiotic resources can be assessed in a meaningful way, enabling a more realistic material availability analysis within life cycle impact assessment. However, a larger set of characterisation factors and further research are needed to verify the applicability of the concept within LCA practice.