Reduce human population by enough and extinction goes back on the agenda long term. There was at least one [1] population bottleneck in the last 70,000 years.

Of course I would've thought "aren't you worried your grandchildren will live miserable, dangerous lives struggling to survive" would be a decent argument but I've encountered no Boomer who seems to worry about it as they excitedly tell me about the coming collapse of something or imminent major war in wherever.

[1] https://www.businessinsider.com/genetic-bottleneck-almost-ki...