Assessing the long-term water footprint of olive grove under changing climate (Apulia, Italy)

Changes in the water balance and an increase in agricultural water requirements are generally expected for the future due to climate change (CC). In this context, sustainable water resources management will play a crucial role in balancing human and ecosystem demands. Going beyond a case study (Locone basin, Apulia, Italy), this paper aims to analyze the water consumption in olive cultivation under CC through the water footprint (WF) approach. Two climate model projections were adopted, MPI-ESM1–2-LR and CMCC-CM-COSMO-CLM, and different scenarios were developed for analyzing the potential effects of the increase in temperature and atmospheric CO2 concentration on the WF components. The Soil and Water Assessment Tool (SWAT+) was used to estimate the WFgreen and WFblue (WFg,b), and crop yield under different environmental conditions. For the baseline (2000–2009), the WFgreen was 831 m3 t−1 and WFblue was 116 m3 t−1. For the future (2040–2049), the climate models project an increase in temperature (up to 1.12°C) and a decrease in rainfall (up to −17 %) compared to the baseline. The results showed that the impact of CC constitutes an important risk for the productivity of olive (up to −17 %). The positive effect of CO2 fertilization (up to 500 ppm) on the crop yield is insufficient to maintain the baseline productivity. To preserve the latter, an increase in irrigation (up to 135 %) is needed with a consequent rise in WFg,b (up to 18 %). These results provide useful insights for agricultural water management under CC.