P.S. I don't think that Vermi can cite where it says that in a perfect world where humans think about humans instead of #1 that the Earth will fall apart with a population of 50 billion people.. or 100 billion people.
How will people get water? Space.
How will people get food? Astro-griculture
How will people get Oxygen? Find a planet with oxygen and use a vacuum to replenish our atmosphere with the other planet's atmosphere.
AGH!! That's just me being a big dumb dummy head again, thinking out of the box, sorry. If you can cite me what to think I'll think thoughts you think should be thought.