O'Neill saw space stations as a way of growing vast amounts of food much more easily than on earth, because there is so much more sunlight.
Sharp limits on food, energy and materials confront us at a time when most of the human race is still poor, and when much of it is on the edge of starvation. We cannot solve that problem by a retreat to a pastoral, machine-free society: there are too many of us to be supported by preindustrial agriculture. In the wealthier areas of the world, we depend on mechanized farming to produce great quantities of food with relatively little human effort; but in much of the world, only-backbreaking labor through every daylight hour yields enough food for bare survival. About two-thirds of the human population is in underdeveloped countries. In those nations only a fifth of the people are adequately fed, while another fifth are "only" undernourished-all the rest suffer from malnutrition in various forms.