Simple.What is really occurring is a reduction in the carrying capacity of the nations. Example: California going to full electric cars by 2035 - the grid can't handle it but they are doing it anyway. A reduction in the ability of the grid through increased demand is a reduction in the carrying capacity. People will move out to other states. If it happens worldwide through crop and energy reductions, you end up with a worldwide reduction carrying capacity and nowhere to go. It's not that the world can't carry the number of people, it's that the carrying capacity has been artificially lowered through politics.
If this is the case, the question becomes why?
Population reduction.
Massive redistribution of wealth.
You, me and everyone else are just in the way.