The idea of underground farming may seem absurd but such "science fiction" notions may become increasingly necessary if the human race is to survive on this planet. With an advanced non-debt financial system (eg. Modern Monetary Theory, or rather something like Transfinancial Economics) it may well be possible to undertake such large scale sustainable projects. The following is a somewhat brief "look" on underground farming.
- The Lunar greenhouse is an underground farm made by Phil Sadles and Gene Giacomelli of the University of Arizona's Controlled Environment Agriculture Center (CEAC) The urine and exhaled air of the astronauts is reused in the system by the plants.