April 27, 2011— -- Columbia University professor Dickson Despommier says that his Vertical Farm Project could save the world as the swelling global population begins to overwhelm the food supply.
In his book "Vertical Farm," Despommier explains that a series of greenhouses stacked on top of each other and placed in urban environments could provide a sustainable source of food as more people migrate into cities.
Despommier predicts that within 20 years, 80 percent of the world's population will live in cities.
"The biggest difficulty we're facing is a misdistribution of resources right now," Despommier told ABC News. "In the near future, we'll have shortages, period."
Vertical farming uses many of the same techniques found in modern greenhouses, but stacks them one on top of the other in order to create vertical farmland that uses much less space than traditional fields. One indoor acre is equivalent to 4-6 outdoor acres or more, depending upon the crop.
"An indoor farmer doesn't pray for rain," Despommier said.
Some of the techniques are based in aeroponics, which is a technology that grows plants using air or mist and not soil, and hydroponics, which grows plants in nutrient and mineral-rich solutions in water, also without using soil.
"You can ask anybody [who lives near greenhouse agriculture] what it's like to taste a nice, delicious tomato in the middle of January if they live in a region with a long winter," Despommier said.
Another potential advantage of vertical farming is a virtual inoculation against weather-related crop failures due to droughts and floods. This has become increasingly more important as climate change affects weather patterns and farmland.
The latest report on global food insecurity by the Food and Agriculture Organization of the United Nations found that every food-producing country in the world had experienced some kind of environmental problem in the last that year that has affected food production.
Until just a few months ago, vertical farming was still just an idea. Since then, a Dutch group has created a vertical farm in the city of 's-Hertogenbosch, and a group of investors is planning another one in Milwaukee.
Watch our "Conversation" with Dr. Dickson Despommier to learn more about this exciting new technology.