Global freshwater criticality: Application of the Water SCARCE method

The escalating anthropogenic use of freshwater across agriculture, industry, and households highlights the importance of assessing not only the physical freshwater availability, but also environmental and socio-economic dimensions of sustainability. While existing studies address water scarcity and resource criticality from individual perspectives, the Water SCARCE method brings these perspectives together by systematically transferring and adapting mineral criticality concepts to freshwater resources, resulting in a novel freshwater criticality assessment. In doing so, the method allows for evaluation that extends beyond conventional scarcity assessments by incorporating supply risk, vulnerability, social and environmental compliance dimensions. This paper further revises and refines the methodology totranslate the conceptual framework to a practical and operational calculation tool. A central aspect is the development of country-specific freshwater criticality characterisation factors, which translate the physical, socio-economic, and environmental indicators into comparable metrics. These characterisation factors were calculated for 156 countries across 14 categories. The results reveal distinct global patterns of freshwater criticality, highlighting the role of governance, resource distribution, and socio-economic conditions in shaping country-level risks beyond purely hydrological constraints. Eritrea, Yemen, and Sudan emerge as the most critical countries, while Norway, the Czech Republic, and Sweden are the least critical. To demonstrate the applicability of the method beyond country level, the Water SCARCE was applied in a product-level case study assessing the freshwater criticality of battery-grade lithium produced in the Salar de Atacama, Chile. The results were analysed alongside a conventional water scarcity assessment. The analysis revealed the same hotspots, but the water footprint method assigned a much lower contribution to lithium carbonate production, reflecting methodological differences. Overall, the results demonstrate that freshwater criticality cannot be fully understood through physical scarcity alone but requires the integration of socio-economic, governance and environmental-related factors. The method provides a comprehensive basis for identifying critical regions for sustainable sourcing and improved supply chain management.