Multiscale assessment of transboundary water-food-energy nexus under climate change in Irtysh River Basin.

Climate change is intensifying water scarcity and amplifying upstream-downstream tensions in transboundary river basins, particularly in Central Asia. We present a multiscale framework integrating hydrological dynamics with the water-food-energy (WFE) nexus to assess climate-driven cross-sectoral trade-offs in Irtysh River Basin. By combining long-term hydroclimatic observations with climate projections, we quantified the effects of temperature and precipitation variability on runoff and evaluated how these changes propagate across interconnected WFE systems. Climate-induced hydrological changes increased irrigation demand, reduced hydropower potential, reshaped agricultural productivity, and intensified regional resource pressures, with distinct responses between upstream and downstream regions. These findings reveal pronounced spatial heterogeneity in climate vulnerability and adaptive capacity, highlighting the need for differentiated adaptation strategies and coordinated transboundary governance. Our study establishes a transferable framework for assessing climate change impacts across the WFE nexus, providing actionable insights for enhancing climate resilience and sustainable resource governance in transboundary river basins.