Chip density and ever more heat-producing peripheral items in the “box” mean we are at the limits of air cooling both in its technical and environmentally desirable senses. Unless we change, costs and reputations will be irreparably damaged. Regional climates where previously defined cooling practices were sufficient to meet technology requirements are now in review, in light of global pressure on sustainability and data centre financial requirements. This session will discuss the key choices data centre operators and customers must make.