Durum wheat is a critical staple crop in arid and semi-arid regions worldwide, that plays a significant role in local food security. Providing essential nutrients and a high protein content, it is widely used for the production of pasta and couscous. Various constraints and drivers affect durum wheat productivity, including biotic and abiotic stressors, agronomic practices, and CO2 concentrations. Their influence varies based on duration and intensity of the stressor, as well as the durum wheat growth phase in which they occur. Drought and heat were shown to act as primary yield limiting factors. Furthermore, the water footprint, a comprehensive measure for the volume of water associated with crop production, helps to analyse durum wheat cultivation from a water-food nexus perspective. Given that climate change is affecting the main influencing factors of durum wheat’s productivity and of its water footprint, such as precipitation, temperature, and atmospheric CO2 levels, its cultivation is expected to undergo alterations as well. In this context, we explore the present state of durum wheat productivity and the potential influence of changing climatic conditions on its future cultivation worldwide. The current state of research on future durum wheat production is characterised by contradictory results, compromising projections of significant declines due to heat and drought stress as well as strong increases in productivity as a consequence of the CO2-fertilisation effect, for the same or nearby locations. Understanding the complex interactions between climate change, durum wheat productivity and the associated water footprint is of great importance to derive sustainable adaptation strategies and move one step closer into ensuring future food and water security.

Agricultural heritage is a cultural pillar of the Mediterranean region, where durum wheat plays a central role in traditional landscapes and food systems. Projected climate change is expected to alter crop productivity and place additional pressure on water resources. This study assesses future variability in durum wheat productivity and related implications for water resource management in Sardinia, Italy, where durum wheat is a major rainfed C3 crop. The AquaCrop-OpenSource model was calibrated to local conditions and applied to simulate historical (1950–2023) and near-future (2024–2050) scenarios using projections from seven climate models. Results indicate a modest increase in average yields under future conditions, accompanied by a higher frequency of crop failures. Elevated atmospheric CO₂ concentrations emerge as the primary driver of yield increases, while changes in precipitation represent the main limiting factor. The role of aid irrigation as an adaptation strategy to stabilize yields and enhance productivity was evaluated. Scenario analysis shows that aid irrigation aimed at preventing crop failure remains sustainable in the near future, requiring approximately 14–17% of current agricultural water use in Sardinia. In contrast, irrigation used to maximize productivity would increase water demand by more than 40%, intensifying competition for water resources.

In urban areas, green roofs are increasingly adopted due to their multiple environmental benefits and their ability to mitigate hydro-meteorological risks. Among them, Multilayer Blue–Green Roofs include an additional storage layer that enhances pluvial flood mitigation by retaining excess water that percolates from the soil layer. This storage layer can also be regulated through a valve that allows controlled release of stored water into the urban drainage system. Existing hydrological models for blue–green roofs typically represent processes such as evapotranspiration, leakage and discharge, but the contribution of condensation from the underlying blue layer to soil-moisture dynamics is largely overlooked, despite monitoring evidence showing measurable moisture gains in the substrate associated with concurrent water loss from the storage layer. This study investigates the influence of condensation generated by upward water-vapor fluxes from the storage layer to the soil, assessing the impacts on the soil-moisture dynamics. The conceptual eco-hydrological model proposed by Viola et al. 2017 to simulate the soil-moisture dynamics of traditional green roofs, has been adapted to represents a Multilayer Blue-Green Roof, accounting for the additional storage layers and condensation dynamics. The Multilayer Blue–Green Roof prototype installed in the Engineering Faculty of the University of Cagliari has been selected as case study to calibrate the proposed model. The prototype has been equipped with sensors to continuously measure temperature, soil moisture, water level and discharge. Three years of collected data are available at high resolution for this Multilayer Blue–Green Roof. Rainfall and relative humidity data have been provided by the weather station network of the Regional Environmental Agency (ARPAS – Agenzia Regionale per la Protezione dell’Ambiente Sardegna). Crop coefficient and mass transfer coefficient have been calibrated for each season with the aim to account for the different vegetation cover. Incorporating condensation processes significantly improved model performance, yielding soil-moisture and water-balance simulations closely aligned with observations. Results highlight condensation as a non-negligible process in Multilayer Blue–Green Roofs hydrology and support its inclusion in future roof modelling frameworks.

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.