We don't need infinite resources. First, we really are not taking up that much space. Sure, if you are in New York, it feels like it. But then look at Utah, and the rest of the midwest, where we haven't even started to fill up space.
We haven't even taking simple actions.
1. Fill Death Valley with ocean water. Since it is below sea level, this will take 2 pipes (1 for ocean to inland sea, and one back so there is a constant flow), a bit of tunneling, and zero long term energy. That inland sea will increase precipitation through the midwest, which will increase snow in mountains, and snow pack, which will cool temperatures. Add in the dead sea, pipe water to and from it.
2. Desalinization is hardly a thing yet. We haven't really embraced desalinization. When Californinia starts to get 95% of its water needs from desalinization, then talk to me about over-utililizing resources.
3. Piping water all over like we pipe oil.
4. Replacing a desert with a forest. What would be the affect on the climate if we replace the Sahara with a forest? We can start with tinted glass domes 3-d printed with a glass 3-d printers, made from sand right there in the Sahara, powered by Solar, and then put in green houses. We could fit 10 billion people in the Sahara with green houses, and we are only 7 billion people today. So again, plenty of space. Then we can do the same to the Gobi.
5. The ocean. We haven't even scratched the surface of what we can do in the ocean. What if we focussed on planting, growing, and harvesting seaweed in the ocean. We could probably solve world hunger.
6. Undergound, we aren't really even trying to build underground cities. We could cut out cities inside mountains (as long as we don't wake a Balrog).
So even without infinite resource, we have plenty of resources. Plenty to do.
But if you stop to think about it, there *are* infinite resources available to us both on and around this earth.
Inifite size 1: You can always go smaller. We have harnessed the power of atoms, with Nuclear, and there is more to harness as we go smaller to quarks, and then infinitely smaller. As technology grows we will find infinte power from inifinitely smaller source.
Infinite direction 2: Space.
Space 1: Next is power expansion. We have yet to harvest wireless power other than solar and a few other lab-only successes. Once we have wireless power, we can have solar panels in space, which is inifite in size, that sends that power to earth.
Note: also what if those Solar panels were between Earth and the Sun, so they provided a small measure of Shade? I call it the Umbrella project. I am going to write a sci-fi novel about it. Stay tuned.
Space 2: Mining. We have the Moon, Mars, Astroid belt. We haven't even started mining the astroid belt. We might find the ability to increase our atmosphere by mining astroids, espicially ones that are mostly frozen elements that make up our air.
Space 3: Human expansion: Lastly is expanding to live in other places than earth. We use the dome technology we have for populating the Sahara to populate the moon, Mars, etc. We could build space stations with plant life. Dirt and water from asteroids and solar and you have an infite firtile space station.
So don't tell me there are limits. Don't act like we need to cut the human popuplation growth. We don't.