Assessing the Effects of Climate Change on Durum Wheat Yields in Mediterranean Regions: A Water-Food Nexus Perspective

In the Mediterranean region, the agricultural sector represents a major water resource consumer and, at the same time, a crucial economic pillar. Future climatic changes are expected to impact agricultural systems, especially through extreme weather events such as droughts and floods, with relevant consequences on the water resource management, especially in semi-arid regions. In this context, understanding the potential variability of durum wheat productivity and irrigation impact on water resources is crucial to ensure sustainable development and efficient water management. This study focuses on durum wheat cultivation in Sardinia (Italy), a key C3 crop in the Mediterranean context, thanks to the good nutritional composition, with a high carbohydrate and protein content. In Sardinia durum wheat is currently grown under rainfed conditions and therefore vulnerable to climatic changes. With the aim to estimate the crop productivity, the AquaCrop-OpenSource model was used, explicitly taking into account the local conditions of climate, soil, sowing time, field management and crop properties. To assess the impact of climate change on Sardinia’s durum wheat productivity, simulations of the attainable yield for historical (1950 -2023) and near future conditions (2024 -2050) were conducted evaluating seven different climatic models (CMCC CM VHR4, EC Earth3P HR, FGOALS f3 H, HiRAM SIT HR, MPI ESM1 2, MRI AGCM3 2 S, NICAM16 8S), that follow the High Resolution Model Intercomparison Project protocol. In the context of a Water-Food nexus analysis, the volume of water needed for irrigation to uphold current durum wheat yields as well as to maximise productivity was estimated, evaluating the potential impact on Sardinian water resources management system. Simulation results indicate a general increase in yields in the future accompanied by a concomitant reduction in growing period duration and a potential drawback in grain quality; at the same time, it is not rare the occurrence of low or zero productivity triggered by winter droughts or summer heat waves. Additionally, the investigation of the impact of individual projected changes in temperature, precipitation and CO₂-concentration reveals that rising CO₂ levels exert the overall highest influence on the enhanced durum wheat productivity.