Future nexus interactions among biodiversity, food, water, health and climate change: assessing trade-offs and synergies

Achieving sustainable and just biodiversity outcomes in the future requires moving beyond treating biodiversity in isolation. Instead, it is essential to account for potential synergies and trade-offs with other key sectors and nexus elements, namely water, food, human health, and climate. These interdependencies are particularly important under conditions of global polycrisis. In this context, scenario analysis offers a powerful tool to systematically explore future interactions within the nexus, as well as the complex interplay among underlying drivers, governance strategies, and specific response options that shape nexus outcomes.This study builds on an extensive review and analysis of over 180 nexus scenarios conducted within the IPBES Nexus Assessment. We cluster the identified scenarios into six distinct nexus scenario archetypes, reflecting different configurations of relationships among the nexus elements, ranging from scenarios with broadly positive outcomes across all elements ("balanced” nexus scenarios) to scenarios dominated by negative outcomes due to siloed approaches prioritising a single sector or goal at the expense of others. In addition, we systematically assess the policy decisions and response options associated with positive and negative outcomes across the scenarios, showing that scenarios based on integrated, cross-sectoral (nexus) approaches tend to produce more equitable and sustainable co-benefits across the domains of biodiversity conservation, climate mitigation and adaptation, water security, food systems, and public health. In contrast, current policy trajectories, characterised by fragmented and siloed decision-making, are associated with compounding risks, including biodiversity loss, climate instability, water stress, food insecurity, and deteriorating health outcomes.Crucially, the scenarios underscore that reaching positive outcomes across nexus elements is possible if leveraging integrated nexus governance. For instance, climate mitigation strategies that combine a holistic mix of interventions, such as nature-based solutions, dietary shifts, and inclusive governance, can simultaneously enhance biodiversity and improve health outcomes, thus delivering co-benefits across multiple nexus dimensions.Our findings highlight the importance of understanding interlinkages among nexus elements and incorporating diverse visions of the future and notions of a good quality of life. Such integrative, scenario-based approaches are essential for informing today’s policy and management decisions, enabling more synergistic and equitable outcomes for both people and nature in the future.