Most of the world's arable land is already under cultivation; the remaining regions are either too cold, arid, wet or mountainous to sustain agriculture as practiced in the first world. In order to increase world food production one must increase the productivity of land already under cultivation by introducing techniques to obtain higher yields or devise systems to bring marginal lands, illsuited to agriculture due to adverse climate and topographical conditions, into production. It is suggested that Arcosanti's passive "energy apron" is such a system and could have the most positive effect when located in areas that have three climatic conditions in common:

Aridity - the greenhouse allows frugal water management by using 1/10th to 1/30th of the water used in open field irrigation;

Cold winters - the growing season can be extended up to 360 days;

and a High percentage of sunny winter days.

Arcosanti, situated in the semi-arid desert highlands of central Arizona, in rugged lava terrain, illsuited to open field mechanized agriculture, shares these conditions and hence has much in common with two-thirds of the world's marginal agricultural land. Successful food production tactics here could have global application.