I read in the newspaper that Philips creates light bulbs that are as good and even better than regular sun light. In that perspective, I believe every city skyscraper should have a farm floor that makes the building self-sustainable in food.
I would go even further. In Hong Kong, you could find a nice club on floor 13, a restaurant on floor 34 and floor 6 even had an indoor soccer field. Per ten floors, at least one floor should have another function than living or working.
I’m not saying it goes that far that it will solve hunger problem but at least, when people prove to be self-sustainable (give them a fish line, not a fish…), it’s empowers them to be more socially engaged.