Vertical farming should be considered as part of food policy. There are a few companies currently working on hydroponics and aquaponics. We should heavily invest in all three of these areas. Agriculture degrades the land (whatever form it takes) and food miles move us away from our carbon targets. Vertical farming can provide local solutions and the more time and money invested the wider range of produce can be offered. It also produces animal fodder cutting the carbon footprint of meat. There could be a lot of land freed up which we know can be used for renewable energy production in the form of green gas mills (pasture used as feedstock - Ecotricity want to do this). Also the soil on land can be "rested", which reduces chemical run off, increases carbon capture by the soil amongst other things.
Vertical farming could become part of the landscape in the way windmills used to be. It need not be an industrial eyesore.