Hydro-climatic stress cascades across water, food, and critical mineral systems

Hydro-climatic shocks increasingly threaten interconnected resource systems, yet their asymmetric propagation across water, food, and critical mineral markets remains poorly understood. This study examines regime-dependent spillover dynamics using a time-varying parameter VAR connectedness framework applied to monthly data (2004–2025) for terrestrial water storage, precipitation, surface water, staple grains (rice, wheat, and maize), and industrial metals (aluminum, copper, and nickel). We find that terrestrial water storage acts as the dominant net transmitter of shocks under negative regimes, while agricultural commodities function as net receivers. Critical metals operate as intermediate transmission channels. Positive regimes exhibit fragmented and weakly integrated spillover structures, confirming that shock propagation is direction-dependent. These findings reveal that hydrological stock deterioration generates cascading sustainability risks across food security and green transition systems. The results directly inform Sustainable Development Goals 2 (Zero Hunger), 6 (Clean Water and Sanitation), and 13 (Climate Action), highlighting the need for water-based early warning systems and integrated resource governance to strengthen systemic resilience.