Apparently, the major players in our international political arena intentionally avoid discussing some of the obvious problems because there is no solution. A key problem underlies the global warming problem, the water problem, the fossil fuel problem, the ocean garbage problem, the tropical forest problem, and many others, but I hope you get the idea.
There are lots of problems created by our ongoing population explosion. That expansion of some six billion people since I was born, going from two billion to eight billion, creates all the problems listed above. We have so many people because we now have the technology and resources to be able to create the food necessary to feed that many people. Actually, if everyone were to go vegetarian we could double that number, and if all humanity were to go all-out vegan we could double that number again.
But those numbers probably would not prove sustainable in the very long run of say a thousand years because there is the need to create the fertilizers to grow the nutrients we need. There may be ways to have plants themselves create nitrogen and other essential things. And there may be ways to create robots as labor to produce human food. The robot “food” to do all of this work is electricity, and that can be created by electricity-generating solar panels.
Yes, there may be technological fixes for food, and perhaps ways of housing ten times the population of humans we now have, but at some point, there must be a stable population. To create a stable population requires some kind of birth control. If we find that to be too repugnant to consider, then nature will step in with natural processes such as famines, wars, and stresses on humans that will bring the total population down to what ever is sustainable at the time.
Without robots and other mechanical ways of creating food, that food might have to be created by human labor. If that comes to pass, the population will drop to lower than the historical levels when food created by human labor because the essential soil will be depleted.
I wrote this grim post in twenty minutes but the analysis seems obvious to me at this moment.