Some may still hope that markets or innovation will quietly resolve the problem, and extraterrestrial data centres may yet do something to help. But water does not behave like other commodities. It is local, finite, and political: unlike rare earths or hydrocarbons, water cannot be stockpiled at scale, substituted or shipped across oceans to smooth out shortages; it must be consumed where it falls or flows. So when water is scarce, there is no global market to arbitrate supply — only hard decisions, made locally, about who goes without. In a century defined by ecological pressure, then, water sits near the top of the hierarchy of risks. This is not because it is unsolvable, but because it is foundational.