Other growth areas include vertical farming, in which lack of space means crops are cultivated in urban high-rises or 'farmscrapers'.

More radical still is an idea that has environmentally minded architects worldwide in a tizz. "Farmscrapers" may become the solution to a bulging population versus diminishing land. Clever hydro- and aeroponic systems mean very little water will be required to grow crops high up in the sky, saving valuable space and resources.

Dr. Dickson Despommier, a professor of environmental sciences and microbiology at Columbia University, believes that "vertical farm" skyscrapers could help feed cities, and fight global warming….And the price tag? Roughly $200 million per farm for startup costs, and the idea is for each 'farmscraper' to be self-sustainable.