[throwaway316943]

Out survives

We have no predators but we do have a lot of existential threats. The more we spread out the more chances we have of surviving. If we sit on our hands and stay put we’ll wind up like the dinosaurs one way or another.

[ganafagol]

There are other alternatives beyond "spreading out" and "sitting on our hands".

Solving world hunger does not need expansion. Stopping climate change does not need expansion. Preventing the upcoming antibiotics crisis does not need expansion. To the contrary, expansion makes all those things worse or has even started them in the first place.

[nine_k]

Stopping world hunger does not need more food, or even fewer people. Humans produce quite enough food to feed everyone already. The problem is distribution.

This problem is twofold. First is that much food is produced far from many poorly nourished people. This problem is totally solvable by modern transport. There are enough charity donations to prevent hunger everywhere.

Second, and most importantly, it's the social structure what prevents ending the hunger where the hunger still is. People prevent production and distribution of food in order to keep the social structures where they are on top, or are fighting to be on top. They themselves are not hungry, and don't care about the rest much.

[ganafagol]

Exactly. These are social and political problems. They won't be solved by expanding. On the contrary, expanding makes them worse.