Santa Clara county has a population density of about 600/km^2, or 0.4 acres per person. If we populate half the Earth's land at this density and make the rest w

Santa Clara county has a population density of about 600/km^2, or 0.4 acres per person. If we populate half the Earth's land at this density and make the rest wilderness, world population would be about 50 billion. The Earth has unlimited energy at this scale for desalination, indoor heating and cooling, etc. In Santa Clara county, dramatic measures aren't even needed. My family of 4 lives on 0.3 acres and it's technically possible to raise all our food here, including some meat. In this drought year we've received ~ 70,000 gallons of rainwater to date. We've used about twice that but it would be easy to cut our use in half by changing the landscaping. Likewise we could make all our energy with a fission reactor in our basement. The actinides in a cubic meter of earth from our yard could power our 5-bedroom home and an EV for over 4 years. Of course it'd be easier to use higher grade ore and share a reactor with neighbors. The whole neighborhood could run on a reactor the size of one of the transformers in the substation down the street. The planet can easily support 50 billion people until the sun destroys it, without even feeling particularly crowded.