A world with 10x less population growth would be a world in which there's an 81% chance neither of us would have ever existed.

True. But also for the worst of us. :)

It's accepted that other species can suffer from overpopulation. We are far more adaptable, but I assume there would be optimal population levels based on technological/political levels. Pandemics, food and energy production, etc. have costs that may outstrip population benefits?

tho obviously happy we exist, can't tell if this is arguing for or against, since we're 10x less than a world that doesn't exist now, so did we need it?