The fear in the past was that humans would grow in population numbers faster than they'd be able to create more food from the land and resources available. Eventually a catastrophic collapse would occur and humans would suffer and perhaps be unable to attain higher goals like civilization or high technology.
"Population, when unchecked, increases in a geometrical ratio, Subsistence, increases only in an arithmetical ratio." (Thomas Malthus)
Thomas Malthus was the first important thinker regarding population, and his views have filtered through many generations to the present.
"Must it not then be acknowledged by an attentive examiner of the histories of mankind, that in every age and in every State in which man has existed, or does now exist. That the increase of population is necessarily limited by the means of subsistence,
That population does invariably increase when the means of subsistence increase, and, that the superior power of population is repressed, and the actual population kept equal to the means of subsistence, by misery and vice." (Thomas Malthus)
And to take Malthus whole, we truly do have to realize that he was writing from a place where the information seemed accurate because the ability to project what humans were able to do, with the green revolution, birth control, and more, was not clear.
Malthus was not a failed thinker however. While he couldn't, and, importantly DIDN'T, accurately perceive the advancements of the future, his concept of an economic terminal point to human population does exist. Perhaps we don't know the ultimate carrying capacity of earth regarding populace and the resources found upon earth, but it is reasonable to argue that there is a terminal point, and that both population and resources are not magical, being able to be manipulated to meet our needs out of thin air. If the earth is a lifeboat, only so many can be afloat before the weight of the masses would sink it.
It is therefore understandable that writers of the arts, writers of science and social scientists would find reasons to fear the growing population of humanity, and the seemingly obvious scarcity of resources. The world population numbers grew but slowly, due to plagues, disasters, wars, and the many things that made human life expectancies low. The advancement of science limited disease, the opening of farming techniques and farms that were aimed not at self sufficiency but mass markets, and the recognition of causes of disaster, and limiting of wars, all served to limit the factors keeping human population low, and raise the ability to survive long enough for people to invest in their children. Prior to modernity, children were not brought into the world solely out of love, or legacy, but as a means of support for old age. Perhaps, though, not in a direct way, but it was a major reason.
Soylent Green was a movie that was based upon similar fears, but came about due to more than Thomas Malthus arguments placed against the back drop of growing human population.
Paul Ehrlich wrote the book The Population Bomb where he foresaw a world crowded like the most thickly crowded city, filled with hungry, sweaty people, each knowing that they had no reason to survive but for survival itself. This book was able to stoke fears due to the social awareness that grew in the 1960s as a result of radical movements on the left, to change the way we perceived normal.
The movement to recognize all people as valuable, not simply those of the West, caused a new awareness of how the numbers of population were growing, and resources were about to stagnate. Right or wrong, The Population Bomb put a scare in all thinkers of social policy, and movies like Soylent Green put those paradigms to visual use.
But, as with any idea, others came to question the seemingly alarmist ideas of the Population Bomb. Julian Simon was an economist who used pure number theory and prices to judge whether resources were scarce. His numbers showed lowering of costs, and prices, and a lack of scarcity despite growing need. And he argued, that more minds meant more potential human agency towards their own solutions and development.
This of course is a subject that is likely to anger some people, as the sides are rather polarized. Poplitiko's goal of bringing the ideas that are alive in society to view through popular culture media won't solve any of the questions. But this should, if you are interested, allow you to begin your own research into the matter, first through popular culture media, and then, perhaps, through academia. As with my previous article regarding Global Warming, I am aware that people will try to see my own political bent through this. However, unlike my Global Warming article, and views there, I am not of a solid opinion regarding this issue. I surely agree with Julian Simon that human potential is the greatest resource, but I can see that the world has issues of scarcity and abundance. And if his views were absolutely correct, such issues would fade, and they are not fading. We are told the future is bright, but it isn't for everyone. To quote the linked article "About 25,000 people die every day of hunger or hunger-related causes, according to the United Nations. This is one person every three and a half seconds ... Unfortunately, it is children who die most often."
To take the simple and straight forward argument that the economics of the free market and mass exchange of resources will distribute fairly, is false. And until that changes, the world, even if it isn't overly populated with still see suffering and inequitable returns upon the world's resources. I don't have an answer. If overpopulation exists, or will exist, I have hope, but as long as 3 of every 4 people who die from hunger are children, I can only say I hope things improve soon.
FACTS ON WORLD HUNGER