> 1km X 1km X 1km underground vertical farm Even if we could only implement vertical farming at a similar level of productivity to traditional agriculture on a

> 1km X 1km X 1km underground vertical farm Even if we could only implement vertical farming at a similar level of productivity to traditional agriculture on a horizontal basis (although it seems from the paper that we could do a lot better than this), with a unit height on the order 1 metre/unit, we could still achieve productive densities hundreds if not thousands of times higher, given sufficient power and building technology.