It is projected that by the year 2050 that nearly 80% of the earth's population will reside in urban centres and that during this time we'll see the human population increase by about 3 billion people during that time.

In the present an astonishing 80% of the land that is suitable is in use with an estimated 109 hectares of new land needed to grow enough to feed the extra 3 billion, if traditional farming practices continue.

So what is the answer?

Could vertical farming, with the practice of producing food in vertically stacked layers be the trick? We spoke with urban agriculture consultant Henry Gordon Smith about this..