From Jared Diamond’s Collapse: How Societies Choose to Fail or Succeed:

The Norse were undone by the same social glue that had enabled them to master Greenland’s difficulties.  That proves to be a common theme throughout history and also in the modern world … : The values to which people cling most stubbornly under inappropriate conditions are those values that were previously the source of their greatest triumphs over adversity.

Diamond’s book is about societies that have succeeded or failed.  Population control and resource/environmental protection are key to a society’s success.  Overpopulation and environmental degradation lead almost invariably to collapse.  This is a graph of standard population growth:

Owen Davis, University of Arizona

Owen Davis, University of Arizona

It shows how a population grows over time.  At first, growth is slow, because there are few individuals reproducing, but growth speeds up as the population increases.  Eventually, growth slows and stabilizes because the population has reached the carrying capacity, that is, the environment can only support so many individuals.

This graph, however, is oversimplified.  In reality, populations often overshoot their carrying capacity and then crash – like this reindeer population:

The population also responded to the high quality and quantity of the forage on the island by increasing rapidly due to a high birth rate and low mortality. By 1963, the density of the reindeer on the island had reached 46.9 per square mile and ratios of fawns and yearlings to adult cows had dropped from 75 and 45 percent respectively, in 1957 to 60 and 26 percent in 1963. Average body weights had decreased from 1957 by 38 percent for adult females and 43 percent for adult males and were comparable to weights of reindeer in domestic herds. Lichens had been completely eliminated as a significant component of the winter diet. Sedges and grasses were expanding into sites previously occupied by lichens. In the late winter of 1963-64, in association with extreme snow accumulation, virtually the entire population of 6,000 reindeer died of starvation. [emphasis mine]

David Klein, University of Alaska

David Klein, University of Alaska

This often results in oscillations – repeating this exponential increase and population crash over and over.

This is a graph of human population growth:

It looks like the beginning of the logistic curve – or the reindeer graph.  It is very likely that we as a species have overshot our carrying capacity.  Our severe environmental problems are caused by the very large  number of people consuming resources.  But will our population decline gradually or crash?

Unlike reindeer, humans have developed many technologies to help us overcome limited resources.  Fertilizer, for example, allows us to grow more food on less land.  But ultimately, humans cannot keep reproducing indefinitely – there are not enough resources and eventually, we would simply run out of room, like bacteria in a petri dish.

Population crashes, like that in the reindeer graph, may not be that frightening on a graph, but in reality, it is horrific.  War, starvation, economic and social collapse are not the overpopulation solution I want to live through.

We must ease the burden on our planet’s resources by consuming less and changing our lifestyles.  Like Diamond makes clear in Collapse, we must also reject some of our closely held values that have led to our current situation.  Growth cannot be the sign of progress – we must instead focus on sustainability.  But even this is a temporary solution.  The reindeer ate less and less and less – and eventually starved.  We should use less, but I don’t want to use so little that life is miserable.

One of the best things we could do as a species to prevent a population crash is to have fewer children.  Many people do not want children, or did not plan to have as many as they did.  We should support people who do not wish to have children, rather than pressuring them to reproduce.  My mother asks about grandchildren often and my grandmother is also anxious for me to have kids.  But I don’t want children!  Sometimes I think I do, but then I realize that I’m just eager to make my family happy. Quite frankly, having children, especially many children, is selfish and irresponsible in our world.

What if we encouraged people to only have children if they really wanted them, and made that possible by making sure that contraceptives were readily and cheaply available?  What if people who do want children very much considered adoption before trying to have a baby?  What if we built our cities differently so that we could walk places and interacted with our neighbors more?  What if we could be part of a supportive community instead of having to create our own by having a family?

I think these what-if’s are not only possible, but necessary, if we want to live a good life.


  1. Mike says:

    Great post.

    Though I disagree with a lot of the proposed solutions out there, I have no doubt that we’ve already overshot our carrying capacity, depending as do on the contribution of ever-diminishing fossil fuels to sustain a low-cost, high energy society.

    I care about doing things the most efficient way, not doing them the way that makes me feel most pure — as many who profess to care about the environment seem to be most concerned with — so I am interested in solutions like the ones you discuss. Fighting over plastic bags and being a “locavore” are paths to distracting ourselves Republican-style while the world collapses around us.

    Actually working on helping people to have fewer children, to move quickly to renewable, sustainable energy — no matter the form it takes — and working to reduce the carbon we spew into the atmosphere are where the real action should be.

    But without reducing population, we’re doomed no matter what we do. My guess for the carrying capacity of the earth with most people living like the average American is about 500 million (living like the average Ugandan makes it only marginally higher). But we probably lack the foresight to get there the easy way, so we’ll get there the hard one.

    Alas for all of us.

  2. Pete Murphy says:

    Perhaps the biggest impediment to a move toward a more sustainable population is economists. Economists (the vast majority) continue to insist that there is no obstacle to further growth that mankind is not clever enough to overcome. And they insist that even a leveling off of population, never mind an actual decline, is a sign of an economy in trouble and headed for collapse. They cannot envision a healthy economy that isn’t dependent on population growth.

    They take this irrational stand because of the black eye given the field of economics when Malthus’ theory about overpopulation and food shortages, published in 1798, seemed to be proven wrong as crop yields grew exponentially. Scientists from other fields mocked economists for wringing their hands while they got to work on solving the problem (at least for the time being). Economists responded by vowing that they would never again give credence to any theory about overpopulation. Now they deride as a “Malthusian,” the economic equivalent of Chicken Little, anyone who expresses concern about overpopulation.

    So now economists have this huge blind spot when it comes to the most overwhelmingly dominant factor behind so many of the problems we face today. Rampant population growth threatens our economy and quality of life. I’m not talking just about the obvious problems that we see in the news – growing dependence on foreign oil, carbon emissions, soaring commodity prices, environmental degradation, etc. I’m talking about the effect upon rising unemployment and poverty in America.

    I should introduce myself. I am the author of a book titled “Five Short Blasts: A New Economic Theory Exposes The Fatal Flaw in Globalization and Its Consequences for America.” To make a long story short, my theory is that, as population density rises beyond some optimum level, per capita consumption of products begins to decline out of the need to conserve space. People who live in crowded conditions simply don’t have enough space to use and store many products. This declining per capita consumption, in the face of rising productivity (per capita output, which always rises), inevitably yields rising unemployment and poverty.

    This theory has huge implications for U.S. policy toward population management. Our policies that encourage high rates of population growth are rooted in the belief of economists that population growth is a good thing, fueling economic growth. Through most of human history, the interests of the common good and business (corporations) were both well-served by continuing population growth. For the common good, we needed more workers to man our factories, producing the goods needed for a high standard of living. This population growth translated into sales volume growth for corporations. Both were happy.

    But, once an optimum population density is breached, their interests diverge. It is in the best interest of the common good to stabilize the population, avoiding an erosion of our quality of life through high unemployment and poverty. However, it is still in the interest of corporations to fuel population growth because, even though per capita consumption goes into decline, total consumption still increases. We now find ourselves in the position of having corporations and economists influencing public policy in a direction that is not in the best interest of the common good.

    If you’re interested in learning more about this important new economic theory, I invite you to visit my web site at OpenWindowPublishingCo.com where you can read the preface, join in my blog discussion and, of course, purchase the book if you like. (It’s also available at Amazon.com.)

    Please forgive the somewhat spammish nature of the previous paragraph. I just don’t know how else to inject this new perspective into the overpopulation debate without drawing attention to the book that explains the theory.

    Pete Murphy
    Author, “Five Short Blasts”

  3. lizbet says:

    I don’t want babies either. Developed nations tend to slow growth by a large margin. Except where religion is involved. Have more catholic babies!

  4. Prof Bob says:

    Have you read the free ebook series on overpopulation and its related problems? Check: http://andgulliverreturns.info It looks at the many problems caused by overpopulation and suggests some solutions–in a sci-fi and non-fictional genre.

  1. […] of the earth is just beyond me. Not to mention that if you do in fact care about the environment, not having kids is one of the best ways to improve it for generations to […]

  2. […] Well, this should change our lifestyles a bit.  Have I mentioned that overpopulation is a problem? […]

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