What is proposed here that differs radically from what now exists is to scale up the concept of indoor farming, in which a wide variety of produce is harvested in quantity enough to sustain even the largest of cities without significantly relying on resources beyond the city limits. Cattle, horses, sheep, goats, and other large farm animals seem to fall well outside the paradigm of urban farming. However, raising a wide variety of fowl and pigs are well within the capabilities of indoor farming. It has been estimated that it will require approximately 300 square feet of intensively farmed indoor space to produce enough food to support a single individual living in an extraterrestrial environment (e.g., on a space station or a colony on the moon or Mars). Working within the framework of these calculations, one vertical farm with an architectural footprint of one square city block and rising up to 30 stories (approximately 3 million square feet) could provide enough nutrition (2,000 calories/day/person) to comfortably accommodate the needs of 50,000 people employing technologies currently available. Constructing the ideal vertical farm with a far greater yield per square foot will require additional research in many areas – hydrobiology, engineering, industrial microbiology, plant and animal genetics, architecture and design, public health, waste management, physics, and urban planning, to name but a few. The vertical farm is a theoretical construct whose time has arrived, for to fail to produce them in quantity for the world at-large in the near future will surely exacerbate the race for the limited amount of remaining natural resources of an already stressed out planet, creating an intolerable social climate
