The Economist's Technology Quarterly from December has a fascinating article about vertical farming. At its simplest, vertical farming requires a bit of rooftop and some hydroponic equipment. Eventually, and perhaps sooner rather than later, high-rise farm buildings could crop up in cities around the world. With the world population set to increase to 9.1 billion by 2050, we're going to need methods like vertical farming to feed everyone. According to the Economist, Professor Dickson Despommier of Columbia University in New York is the "progenitor" of vertical farming. Professor Despommier's recently published book, The Vertical Farm, has received mixed reviews, which is to be expected -- the book is a sociological manifesto, after all. Still, from what I see on Amazon's page the book is lovely, with several futuristic imaginings of vertical farm buildings. I think one of the main selling points for me to see this type of technology flourish is the ability for a vertical farm to provide local food to urban dwellers. Cities of a certain size can rarely support themselves from their local environs. Vertical farming would return that ability to the urban environment. New York city could become a world breadbasket. I think that is astounding, and I think I'll pick up Professor Despommier's book and judge his opinions for myself.
P.S. The Babbage Blog on the Economist's site also has this: Three views of the vertical farm