Oh ok, that's a tough question. I'm of the opinion the world is ridiculously over-populated and that it needs to be reduced. The novel Logan's Run handled the issue pretty well, however that's just a book and that method may not be popular. The novel Inferno by Dan Brown also makes a suggestion to address the population issues.
We could make better use of the remote uninhabitable areas of the planet through regeneration and greening or maybe colonise the moon: The plague that is humanity finding new environments to destroy.
I don't know what the answer is however this post was inspired by a History Channel show I watched about pandemics. In it it was stated that the World Health Organisation (WHO) expect a catastrophic pandemic to sweep the world the result of which will be millions and millions of deaths. They actually expect it; It's not an "if" but a "when". Maybe these things happen to realign the population.
Humans have a tendency to always want more. More this and more that and so use up resources, we are destructive to ourselves and the environment and uncaring, generally, of our impact upon the other inhabitants and the world itself.
In my opinion the world would be better off without us.
I know opinions like mine will not be widely accepted however I still hold it. We, humans, are a plague on the world.
Personally, i will rather support the opinion of decongesting the spaces we are already populating and make use of the spaces which are still unused, rather than reducing the world population.
If we say the world's population should be reduced, the question is "how ?". Rumour mills have it that there are ongoing programmes aimed at reducing the world's population. Only time can tell if they will be sustainable.
I will go through the books you have cited and learn more.
Thank you so much for opening my mind on this topic.