HyIR 0.1 (HYdrological and Industrial Resilience): A Global Hydrological Aggregation Framework for Translating CMIP6 Climate Projections into Freshwater Availability Scenarios

Abstract. Climate change is altering the global water cycle with direct consequences for water availability and the resilience of human activities. To support prospective assessment of freshwater availability under contrasting socioeconomic trajectories, we introduce HyIR (HYdrological and Industrial Resilience), a global-scale hydrological aggregation framework designed to translate CMIP6 (Coupled Model Intercomparison Project Phase) climate projections into scenario-consistent estimates of freshwater storage and fluxes across key freshwater availability compartments.

This paper presents the hydrological aggregator of HyIR 0.1, forced by CMIP6 precipitation, evapotranspiration, and runoff fields covering the historical period (1850–2014) and future Shared Socioeconomic Pathways (2015–2100). The framework propagates these forcings through three coupled storage and routing components: surface water body storage, groundwater storage, and river network routing, grounded in global geophysical datasets. It provides explicit estimates of water stock evolution and exchanges between rivers, lakes and reservoirs, and groundwater storage compartments. A validation against observed daily river discharge from the Global Runoff Data Centre and the Global Flood Awareness System reanalysis is presented for a proof-of-concept application forced by the Taiwanese Earth System Model TaiESM1 HyIR is intended as a decision-support tool for long-term freshwater availability assessment, with particular relevance to water-dependent industries. In contrast to climate impact studies that report river discharge as the primary indicator, HyIR provides source-specific indicators with explicit storage accounting across rivers, lakes and reservoirs, and groundwater storage compartments.