Middle-income consumption in developing economies is a key driver of global freshwater overshoot

Global water scarcity is increasingly shaped not only by where water is used, but by who consumes water-intensive goods through global supply chains. Yet it remains unclear how rising consumption across income groups in developed and developing economies translates into unequal pressure on freshwater systems. Here we develop a bottom-up framework that links freshwater boundary overshoot at 5-arcmin resolution to final consumers, allowing us to quantify consumption-driven water overshoot footprints for ten income groups across 40 developed and 205 developing economies. We find that middle-income households in developing economies are the dominant contributors to global freshwater overshoot, accounting for 35% of the total footprint—surpassing the contribution of high-income households worldwide. This challenges the prevailing assumption that global water stress is mainly driven by affluent consumers in rich countries. While efficiency improvements could reduce overshoot footprints across developed economies by an average of 36%, in many developing economies rapid middle-class consumption growth combined with dependence on water-scarce supply regions leads to rising overshoot, with 29 countries experiencing an average increase of 12% despite technological gains. Consequently, middle-income households in South and Central Asia, East Africa and West Africa face particularly high water-supply risks as consumption expands. These results indicate that future water–food–energy–environment sustainability will critically depend on how emerging middle classes in developing economies are guided, highlighting the need for demand-side policies and trade-aware water governance beyond targeting only high-income consumers.