I agree, overpopulation is a problem. In fact I see it as the MAIN problem and is the cause for nearly every other "problem" that human kind faces. I believe that problems that are not caused by over population are actually part of the solution.

Climate change? Caused by too many people.

Potable water shortage? Caused by too many people.

Please be clear. We are in a battle to save modern civilization. A lot of people talk about saving the earth. This is a mis-conception. The earth will be fine. It has survived for millions of years undergoing drastic changes, both fast and slow. It may look different when humans are gone, but it will still be here.

I believe the solution has two parts. First, we have to find a non-polluting, infinitely renewable source of energy that does not require tons of resources or continue to alter our environment. A true fusion reactor is the only thing on the radar at this point.

Second, we have to find a way to make our communities healthy and prosperous with NO growth. The earth is a finite resource in many ways. Any growth, even "sustainable growth" is a path that will sooner or later lead modern civilization to a dead end.

As you point out, many signs are there on the wall. If we don't change course, modern civilization will collapse and the humans that are left will be forced to return to subsistance farming and/or hunter/gatherer communities. This might take a while. Or it might happen sooner than you might think in localized places around the earth.

Bottom line: For the long game, man kind is on a dead end path unless we can find a stable population level that the earth can support AND we stop using non-renewable, non-reusable resources.