Current and future blue water availability for agriculture in the Mediterranean

The current and future water availability for Mediterranean basins was assessed under different climate and policy scenarios. The high-resolution GIS-based WAPA model (Water Availability and Adaptation Policy Analysis) was used to obtain potential water availability under a set of realistic hypotheses. Diverse data sets were compiled on meteorological variables, water resources, runoff, land cover, and population density to create a geospatial database that covers river basins that drain into the Mediterranean Sea. The model was forced with the results of the global hydrological models H08 and CWatM for ISIMIP (Inter-Sectoral Impact Model Intercomparison Project) scenarios. These two hydrological models were forced with climate drivers for three historical scenarios (obsclim, picontrol, and historical), which define a baseline, and three future scenarios (ssp126, ssp370 and ssp585) provided by the sixth assessment report of IPCC (2023). A high-resolution map of the potential availability of water for irrigation was developed in Mediterranean basins. The allocation of water for irrigation is subordinated to the urban supply (drinking water) and for the conservation of river ecosystems. The results indicate that changes in hydrological regimes across the region are expected to have a significant impact on future water availability. The proposed approach provides a valuable tool for decision makers and stakeholders for the identification of areas vulnerable to changes in water availability. The information generated in this study, high-resolution spatial outputs and detailed water availability estimates, could work as a relevant input for integrated water resource management and climate change adaptation planning. This research offers a robust framework for assessing water resources under changing climate, applicable to other regions facing similar challenges. In summary, our study provides useful information to policymakers and stakeholders, helping them to make informed decisions to develop adaptive measures for sustainable water management under uncertain future climate conditions.