Well you are going to get your wish Dave, we are about to have a great big die-back. Here's the deal though, how it happens is key.

1% excess mortality for 50 years is a manageable decline of 50% by 2070. Although you should read about the effects of depopulation on a culture. The Japanese experience is sobering. It's not going to be "Yea, there's 50% fewer people so rent is cheap and food is plentiful."

50% excess mortality in one year would probably crash our civilization just as Umair predicts. Because those 50% won't go quietly. They will want to make sure that they take some of the rest of us with them.

It will be like Riverworld when half the food generators break down one day. In the end the population would probably shrink by 75-80% maybe even more. Depends on the weapons used.

It could wind up being a 99% die-back if it gets really ugly.

OVERPOPULATION IS NO LONGER A PROBLEM.

It was always a racist trope anyway. The 15% of the planet using 65% of the planetary resources complaing about how there's too many "of them" (meaning POC) and how their populations need to shrink.