Two Trend Lines, Often Confused
Water intensity per unit of compute and total water demand are separate quantities. Efficiency gains do not automatically reduce total draw.
Intensity
Per-unit water intensity has been falling as operators raise operating temperatures, adopt direct-to-chip liquid cooling, and move to closed loops. This is a genuine engineering trend and is visible in published WUE figures.
Total demand
Total demand depends on how much compute is built. Projections of data center electricity growth driven by AI vary widely between publishers and rest on assumptions about build-out rates, chip efficiency and utilisation. All such projections are stamped ESTIMATE in this archive, and none are treated as facts about the future.
The Jevons problem
Historically, making a resource cheaper to use per unit has often increased total use rather than reducing it. Whether efficiency gains in cooling outrun growth in compute is the actual question, and it is currently unresolved.
What would resolve it
Multi-year absolute water consumption figures by operator and by region, reported on a consistent methodology. Fragments of this exist; a comparable series does not.