Revisiting metal footprints of nations with a reserve-side scarcity indicator

Abstract

Metals play a vital role in economic development, and resource scarcity is currently a huge global challenge. To better understand the economic drivers underlying metal resource depletion, it is critical to quantify the scarcity-weighted metal footprints from different perspectives. Previous studies have estimated the scarcity-weighted metal footprints from the extraction perspective (representing consumed resources out of the total available resources). However, the scarcity-weighted metal footprints from a reserve perspective have been overlooked, indicating that the global metal supply insecurity cannot be revealed comprehensively. This study quantified the global scarcity-weighted metal footprints for 13 kinds of metals by combining a reserve-based scarcity indicator with an environmentally-extended multi-regional input-output model. We also compared the reserve-based scarcity results with that of extraction-based scarcity and non-weighted. Results show that the reserve-side scarcity indicator brings to light the metal scarcity risks of some nations with small reserves (e.g., Mexico and Ireland). For example, Ireland ranked 69th and 55th in terms of actual extraction and extraction-side scarcity-weighted footprints, but 4th in terms of reserve-based scarcity-weighted footprints. Moreover, the scarcity-weighted footprints of some nations with large metal reserves (e.g., Brazil and Australia) are overestimated by the traditional extraction-based indicator. The reserve-based scarcity-weighted metal footprints can help nations identify metal supply risks from the viewpoint of their natural resource endowment. The findings can provide new insights for policymakers around the world when assessing metal resource sustainability to achieve effective resource management.