What, what North Korea? Korth Norea just hold on, the way to go!
Actually you could apparently fit the entire world's population in Texas with enough land to farm and feed themselves if done by absolute efficiency.
Really it's a matter of how wasteful human society is, not how many humans there are, though it's very easy to see it either way.
Nothing can be done with absolute efficiency, their not robots, imagine the living condition of this "absolute efficiency", for me it sounds like living in a box.
Humans, just like any other animal require space.