The need for strategic water actions within planetary boundaries
Summary
Water is the bloodstream of the planet [1], a cornerstone of sustaining 10 billion people by 2050. With climate change impacts intensifying and growing resource pressures, strategic actions are required to remain within the safe operating space for humanity.
Humanity has already crossed seven of the nine Planetary Boundaries (PBs), with the ocean acidification boundary transgression detected earlier in 2025 [2,3]. While all nine boundaries are interconnected, climate change, freshwater change, biodiversity integrity decline, biogeochemical flow modification, and the overloading with novel entities directly affect water functions within the Earth System [4]. Advancements in large-scale water systems research [5] have shown the role of water in being responsible for feedback connections between land, ocean, and atmosphere.
The seemingly isolated crises, such as deforestation, nutrient pollution, loss of glacier volume (to name a few), are interconnected through and with freshwater and its quantity and quality. Moreover, water systems are where some of the transgressions of PBs occur: fish die-offs, pollution by novel entities, and loss of river-floodplain connectivity have been observed in rivers and lakes worldwide.
Overall, humanity has driven water systems beyond their sustainable limits [6,7], taking a destabilising route toward a volatile future. Unsustainable withdrawals, environmental pollution, and inadequate water governance are occurring globally, affecting both local and large-scale water systems and the hydrosphere as a whole.
