Vertical farms, many stories high, will be situated in the heart of the world's urban centers. They offer the promise of urban renewal, sustainable production of a safe and varied food supply, and year-round crop production.
It took humans 10,000 years to learn how to grow most of the crops we now take for granted. Along the way, we despoiled most of the land we worked, often turning verdant, natural ecozones into semi-arid deserts. Within that same time frame, we evolved into an urban species, in which 60% of the human population now lives vertically in cities.
The time is at hand for us to learn how to safely grow our food inside environmentally controlled multistory buildings within urban centers. If we do not, then in just another 50 years, the next 3 billion people will surely go hungry, and the world will become a much more unpleasant place in which to live.