Yes great conversation. It is true we impacting the whole planet. By 5% I mean concentrated urban population. There is a lot of space around the cities not occupied by wild life. We can use hydroponics and vertical farms in the suburban area. Skyscrapers for food is just not the way in my opinion. Nations build skyscrapers mostly for prestige not because they need them so badly... There are new materials. Nanotubes are promising but we can’t manufacture them in big industrial scale. No buildings from nanotubes any time soon...
Cheers :)