The question is whether we'll actually face mass starvation because of unsustainable use of non-renewable resources. Nothing you've said above indicates to me

The question is whether we'll actually face mass starvation because of unsustainable use of non-renewable resources. Nothing you've said above indicates to me what you think the answer to that question is. If all you mean is that birth rates are going to drop, well, that's already been happening for a long time.