Expansion of greenhouses alters water use and underscores the need to balance food and water security in Mediterranean catchments

Abstract Greenhouse agriculture is increasingly vital for food security. Yet, its catchment-scale hydrological effects remain poorly understood. We develop an integrated framework combining greenhouse climate modelling and remote sensing of land cover with the physically based CATchment HYdrology (CATHY) surface–subsurface hydrological model. We apply it to the Piana del Sele district in southern Italy to assess trade-offs under land use and climate change scenarios. Our simulations show that, compared to open fields, greenhouses theoretically reduce evapotranspiration; however, their effects on irrigation requirements depend strongly on the timing of crop cycles relative to rainfall. Moreover, greenhouses increase streamflow and reduce groundwater storage. Climate change intensifies summer irrigation demand, although halting greenhouse cultivation in summer mitigates this pressure. These results demonstrate how greenhouse expansion reshapes regional water balances and highlight the need for integrated modelling to inform water management and provide a transferable basis for policies balancing food production and water security.