Lithium and Water: Why Hydrological Limits Will Define a Just Energy Transition

Lithium is widely portrayed as a cornerstone of the global energy transition. Yet prevailing narratives conceptualize lithium primarily as a mineral resource while treating water impacts as secondary externalities. This Perspective argues that in arid and hyper-arid salt-flat systems, lithium extraction is fundamentally constrained by hydrological boundaries rather than by mineral availability or technological efficiency. Using the Salar de Atacama in northern Chile as an emblematic global case, we contend that brine-based lithium extraction constitutes a large-scale intervention in coupled hydrosocial systems, directly implicating a boundary for freshwater. We challenge techno-optimistic expectations surrounding efficiency improvements and emerging technologies such as direct lithium extraction, emphasizing instead cumulative impacts, persistent uncertainty, and uneven distributions of risk and benefit. Building on the water boundaries framework, we propose a shift toward water-bounded lithium governance grounded in basin-scale extraction limits, precaution under uncertainty, legal recognition of brines as water, and meaningful indigenous participation linked to extraction thresholds. Without re-centering water as the defining constraint, the energy transition risks reproducing environmental degradation and social injustice under the guise of sustainability.