If the trend doesn't reverse, it's mathematically guaranteed.

But realistically, I agree. Civilizational collapse would happen long before extinction, which seems like it would almost certainly return the birth rate back to pre-industrial levels. I just don't think that's a desirable outcome either.

Or, even more realistically, nations with state religions that effectively outlaw birth control and/or women's rights will take over the world, and nations which don't do those things will collapse. That also seems like a bad outcome to me.

Point is, I don't think it's wise to treat this like it's not a problem.

It's not a problem. Go look at a graph of historical world population: https://en.wikipedia.org/wiki/World_population#/media/File%3...

It's virtually flat for eons, and then in the last 100 years it shoots up like a rocket. We didn't hit the first billion people until 1800, but the 8th billion took only 11 years. (2011-2022)

This rate of exponential growth was never sustainable, and it's normal and natural that it's leveling off now.