I can sort of see this working if fusion can be made to work in the next few years. But for the sake of the rest of the eco-system I hope man doesnt get anywhere near to that population.
Only 0.000000724654% of it reaches the Earth. That’s 7.24654 billionths of the Sun’s total light.
the earth receives about 274 million gigawatt-years of solar energy
Put another way, the solar energy hitting the earth exceeds the total energy consumed by humanity by a factor of over 20,000 times.
And thats only only 0.000000724654% of the suns output. Now once we start harvesting our relatively unlimited power source food will no longer be a problem. Build 100 story greenhouse's etc.
I am hardly concerned about our future growth, considering we now have plans to start mining bodys in space. Perfect launch spot for providing our future energy needs. In fact I wouldn't be supprised if the energy is the main factor in planetary resources future plan to add trillions of dollars to the gdp.
We need new resources in the next couple of decades (at the outside IMO, ie eariler would be better). Do you realistically see us harvesting a varied collection of minerals from space in that sort of time-scale.
Algae based bio fuels sounds promising.
> replace plastics
If we stop using oil for fuel, there's plenty left for plastics. Oh, and carbon fibre is promising.
> What are you going to feed your 20 billion?
Food. There's plenty of unused room for it, and even then, there's hydroponics. Solve desalination, or hook up a cheap abundant energy source to what we already have, and there's even more room.