From CNN Food&Health Correspondent Holly Firfer

CORDES JUNCTION, Arizona (CNN) -- Driving north through the Arizona desert -- halfway between Phoenix and Flagstaff -- is an unusual sight: a futuristic complex of concrete structures called Arcosanti.

"Arcosanti is a prototype concept which Paolo calls arcology," explains Roger Tomalty, a founding member of the community. "Arcology comes from two words, architecture and ecology."

Paolo is Paolo Soleri, the Italian architect who dreamed of an energy-efficient town that focuses on preserving agriculture -- and financed it selling the famed Soleri wind bells fashioned from ceramics and bronze.

"The major problem that we are facing on this planet is exponential population growth," says Tomalty. "How do we provide food for the world's growing population? There are only two ways to do that: You either increase your yields of lands that are already under cultivation, or you attempt to bring into cultivation lands that are marginal. And two-thirds of the planet are really marginal lands."

In 1970, Soleri began to build his dream of a non-profit experimental community. Twenty-eight years later, there are four buildings that house hundreds of residents, and two main greenhouses that serve as laboratories. Future plans include a larger greenhouse along the mountainside which would allow a variety of crops to be grown year-round, regardless of the season.

Water isn't the problem you might think for desert food growing. There are three wells here on site, and with a greenhouse the growers only need 1/30th of the water that would normally be required to grow produce in the desert.

Another design of this "urban laboratory" is a functional, but edible, landscape.

"The grapes are an edible food crop and at the same time provide shade during the heat of the summer," Tomalty says. "And ... its leaves fall off allowing maximum sun penetration during the cold season."

Rosemary, lettuce, carrots, even olive trees provide food that is used in the bakery or the cafe daily.

Critics express frustration that until the larger greenhouses are built, this 28-year-old project can not address the problems of agricultural depletion. But, Tomalty explains, it took centuries for the world to deplete its agricultural resources, and it will just take more time to try to come up with some answers.