It is the "elephant" in the room. Everyone can see it, gets used to it and eventually they talk about other things and ignore it.
----- ----- -----
Most people know that we are over-populated and also that it is the main source of many of our human problems.
It is well known in the scientific community that every species on Earth, humans included, will reproduce until their population exceeds the resources needed to sustain it (food, space, etc.) unless something else trims its numbers. It is natural and it has occurred often with humans in historical times. Occurrences of human overpopulation have been local but is now worldwide.
It is also part of nature that after overextending the population, corrections will follow, often by famine during less than optimal seasons of food supply, along with other deaths caused by a weakened population and by acts of desperation. This also has happened with humans and will continue to occur.
For people, famine is only one possibility from a long list of natural and man-made disasters, at least one of which will destroy a very large percentage of the population.
Our population WILL be reduced, that is a certainty. When it occurs, for humans it will be the most terrible tragedy in recorded history.
For nature, it will just be normal processes.
(Survivors will blame the correction on various factions, governments, sin, laws, religions, demons, deities or various individual people.)