[riskable]

The big assumption here is that increasing birthrates (above replacement level) is somehow the ideal outcome of a society.

What if the ideal outcome is that humans populations shrink to 1/100th their current size and most "work" gets done by machines? Wouldn't that be vastly more efficient?

[FooBarBizBazz]

If there were zero people, no work would be required, and thus no machines either. The environment would just do whatever it wanted. This would be more efficient still.

[jimbokun]

Efficient at accomplishing which goals?

Why stop at 1/100th? How about eliminating all of humanity? Why would the universe be worse off with no humans in it?

Why not eliminating all life on Earth? What makes life inherently more valuable than a sterile rock floating through space?

[throw_nbvc1234]

The 2 high level problems with this line of thought: Who decides what we optimize for ("vastly more efficient") and Is this something that "should" have a single target across a society or across the world, or is this something that individuals or groups should decide for themselves. This line of thought can very easily shift into "worlds super elite aim to commit genocide in order to save the planet".

I do personally wonder (in a sci-fi dystopian novel sense) if the worst case climate change scenario would just end up with 99% of humans dying and the 1% that survive in isolated locations becoming a more sustainable civilization until technology catches back up and allows humans to re-populate the world to today's levels (or just leave to mars).