Climate change impact assessment in a mountainous rural basin in Greece

Climate change is projected to create substantial challenges for water resources, especially in regions like the Mediterranean, recognized as a climate change hotspot with multiple interconnected risks. This study aims to introduce a climate change impact assessment framework for the Platanovrisi mountainous river basin, Greece, which is part of the Nestos/Mesta river basin. The GR2M hydrological model was calibrated–validated using observed rainfall, temperature and streamflow data, and applied to assess climate change impacts, which were evaluated based on projections from three climate models (i.e., GFDL-ESM4, MPI-ESM1-2-HR and IPSL-CM6A-LR) and two Shared Socioeconomic Pathways (SSP) scenarios (i.e., SSP1-2.6 and SSP5-8.5). The results indicated that between 2015 and 2050, annual precipitation and discharge are projected to decrease by 13%–23% and 32%–47%, respectively, while the average temperature is expected to rise by approximately 13% (around 1°C) compared to the historical period of 1974–2014. In addition, notable changes were observed in annual and seasonal water flow regimes, with a net reduction in river flow during winter and spring, and a mild increase in autumn and summer. These changes could pose challenges for hydropower generation, irrigation water storage and agriculture, and maintenance of ecological flows. The study also highlighted significant sensitivity and variability in rainfall, evapotranspiration, and river flows depending on the selected climate model and scenario. The results can provide valuable guidance for practitioners and decision-makers to develop adaptation and mitigation strategies for sustainable water resources management in the face of climate change.