Water and food: sustainability of global agricultural systems and their impacts on water resources and aquatic biodiversity. 

The complex interactions between water and food systems are central to global sustainability challenges. Agriculture, the largest consumer of freshwater, plays a pivotal role in shaping water quantity and quality worldwide. The intensification of food production has led to widespread environmental damages, including groundwater depletion, nutrient pollution and biodiversity loss. Integrated and inter-disciplinary approaches are essential to address these interconnected issues. This presentation explores the global-scale interactions between water resources and food systems, focusing on agricultural water demand, virtual water trade, and the impacts of nutrient pollution on aquatic ecosystems and biodiversity.Virtual water trade, which accounts for the transfer of water embedded in traded agricultural goods, has become a crucial component of global food systems. The effects of food trade on water resources is variable, with sometimes an overall efficient, water-saving outcome, and in other cases, increasing depletion of local water resources in exporting nations. Besides, land-use and land-use change driven by the expansion of agricultural activities are significant contributors to terrestrial biodiversity loss, due to habitat conversion and climate change.In addition to water quantity, the quality of water resources is severely impacted by agricultural inputs, particularly nitrogen and phosphorus fertilizers. Excessive nutrient application can lead to eutrophication, algal blooms, and hypoxic zones, threatening aquatic biodiversity and the associated ecosystem services.This presentation will discuss findings from hydrological, agricultural, and life cycle assessment (LCA) models to evaluate the global-scale impacts of agricultural practices on water availability, quality, and ecosystem health.Our results reveal that current agricultural practices are unsustainable for many regions, with high water-use intensity and excess fertiliser application leading to significant water scarcity and biodiversity loss. The findings underscore the urgent need for sustainable interventions, including adopting more drought-resistant crop varieties and livestock species, optimizing fertilizer application, shifting diets towards less resource-intensive products, and leveraging virtual water trade to reduce stress in vulnerable regions.This research contributes to understanding the global interplay between water and food systems, supporting mitigation interventions. By aligning with the session's objectives to address large-scale water management challenges, it advocates for interdisciplinary collaboration and scalable solutions that integrate advanced modelling, policy frameworks, and sustainable practices. This approach is vital to preserving aquatic and terrestrial biodiversity, ensuring food security, and achieving long-term water sustainability.