The more crowded people get the more primitive they become. This is a fact beyond fact. Civilization and humanitiy are luxuries we amuse ourselves with when resources are plentiful, the second they starting getting scarce that facade falls away and revert to the animals we truly are at heart and have been for much longer than we have been civilized men.
It's got nothing to do with race, religion or any of those such things(check the history of every ethnic, race, religion etc for further proof of this). Those are simply excuses to divide and reduce our numbers.
And what most people don't realize...space itself is a resource, a precious one.
People can think of all the alternatives they want, but the solution coded into our DNA, every last one of us, is to kill each other off to create more space.
The world for the first time is reaching that habitable space and resource limit globally...it's about to get much worse than it has ever been before. I don't mean in the next couple of months...but most likely in the next century or so.
I have zero faith that our more recently evolved analytical brain will win over our much older emotional one, it never has before.