Dangers of Human Overpopulation

Ever since Thomas Malthus, we know that population growth is exponential, while the source of food from using the land is arithmetic. At the site worldmeter, it is reported that the world population in 1800 was 1 billion, in 1930 it became 2 billion, in 1974 it became 4 billion. Currently in 2021, it is nearly 7.9 billion.

The main and imminent danger from overpopulation and its effects is the destruction of the ecosystem. This means a disruption of climate, sea rises, pollution, species extinction.

Another effect is a depletion of resources — primarily food and water. And, as Jared Diamond noticed, the killings in Rwanda were not just due to ethnic hatred, but also due to a scarcity of subsistence land. [See, Jared Diamond, “Malthus in Africa: Rwanda’s Genocide,” Collapse, 2005]

Adding overpopulation and scarcity of resources to war and violence, the result is massive migrations of people into Europe and into the United States.

Today, on facebook, I was reminded of experiments done with mice and rats in overpopulated conditions (with adequate food and water) on behavior patterns which lead to extinction. I remember reading in the Scientific American in 1962, John Calhoun’s article “Population Density and Social Pathology.”

The one that today caught my attention is the experiment of John B. Calhoun; variously called “mouse utopia,” “behavioral sink,” and “universe 25.” Here is the account of the experiment:

See also: What Humans Can Learn from Calhoun’s Rodent Utopia

Extinction Rebellion

Today is the second day of the demonstration of the Extinction Rebellion in London. I am fully in sympathy with this movement to force governments to stop carbon dioxide emissions. But I am skeptical that this movement will succeed. And, after all, they are not addressing the underlying cause of our situation — overpopulation.

See also the interview with the co-founder of the Extinction Rebellion, Roger Hallam.


I know that it is very difficult to predict with any accuracy about what will happen to humans — there are too many factors to consider. Nonetheless, there are some generalizations which can be made. One is that the sun will burn out is some 4 to 5 billion years. Another is that given finite resources, infinite growth is impossible. It is this last generalization which has been at the horizon of my thinking — made explicit by Thomas Malthus, who in 1789 published an essay noting that resources (specifically food) grow arithmetically, while populations grow exponentially. The conclusion seemed obvious to me: there is a limit to growth. And a report by that name, “The Limits to Growth” was published in 1973, using a computer to take into account various factors. [Here is a documentary about this project:

The criticism was that the predictions failed. This is true. But the claim that there is a limit to growth with finite resources seems to me to be a truism, as does Paul Ehrich’s “The Population Bomb” (1968). Again, the criticism of these books was not that there is a population problem, but a disagreement about the severity of it, and what will take care of this problem.

We are now living in the midst of an ecological crisis, as well as with other possible global collapses. This impending sense of collapse has been analyzed and proclaimed by a host of people. One of them is Jared Diamond in his book “Collapse” (2005). Below is his 2003 TED talk on this subject:

Recently, I came across the compelling documentary film “Prophets of Doom” (2011):

It includes the following six “prophets”:

  • Michael Ruppert (1951-2014): “Confronting Collapse,” “Crossing the Rubicon”
  • Nathan Hagens
  • John Cronin: “The Riverkeepers”
  • James Howard Kunstler: “The Long Emergency,” “Home From Nowhere”
  • Hugo De Garis
  • Robert Gleason: “End of Days”

    Chris Hedges, The Myth of Progress and the Collapse of Complex Societies

    Kirkpatrick Sale, The Collapse of 2020, 2020.

  • Greatest Problem in the World

    David Pimentel, “FOOD, LAND, POPULATION and the U.S. ECONOMY,” 1994.

    Andrew Chrucky, The Greatest Problem in the World, 1985.

    Paul R. Ehrlich & Anne H. Ehrlich, The Population Explosion, 1990.

    Thomas Malthus, An Essay on the Principle of Population, 1798.

    Antony Flew, Introduction to Thomas Malthus’ An Essay on the Principle of Population (1970)