By James Walker, Ph.D.
This is the first of three articles to examine the human population: its development, outlook, and consequences.
Part I Thomas Malthus identifies the problem
Economic and population growth was very slow in ancient, medieval, and early modern times. It is estimated that in the Roman Empire, the world population was about 300 million people. Most lived at a subsistence level. Then, in the mid-18th century, what we now call the Industrial Revolution began. It progressed slowly but gathered speed and power like a snowball rolling downhill. Some of the early steps were:
In 1769, James Watt invented the steam engine, making an amount of power heretofore undreamed of available to people.
In the 1770s, England developed a canal system, allowing heavy bulk goods such as coal and iron ore to be cheaply conveyed over long distances.
The enclosure movement that began in England in the 1750s transformed agriculture from a cottage industry of subsistence farmers to a much more efficient agribusiness.
In 1775, Edmond Cartwright invented the power loom, allowing masses of cheap fabric to be woven easily.
In 1776, Adam Smith, a University of Edinburgh professor, wrote his blockbuster book The Wealth of Nations, describing the workings of the rising economic system of capitalism.
Economic output began to rise at an accelerating pace, as did the population, which reached 1 billion in 1804. In 1799, an English clergyman and amateur economist by the name of Thomas Malthus produced another blockbuster book, his Essay on the Principle of Population, which has been hotly debated ever since. It was an early, simple mathematical model based on the following assumptions:
The propensity for sexual intercourse between men and women will always remain the same.
The food supply would, at best, increase in an arithmetic progression. Arithmetic progression rises by a constant amount in each Period (year). Let us say 10, 15, 20, 25 increase in this example by five yearly.
The population would tend to grow by a constant percentage each year, as does compound interest. This growth is called a geometric progression. At a continuous growth rate in one’s investment portfolio of, say, 10%, it would yield a progression of 100, 110, 121, 133, 146, 161, and so on. Each year’s increase is more significant than the last year’s increase.
If we plot these two functions on a graph, the arithmetic progression will show an upward-sloping straight line, while the geometric progression will have an upward-bending curved line, as Figure 1 shows.
Figure 1
Figure 2
It does not matter how steep the slope of the arithmetic progression is or how small the proportion of the increase in the geometric progression might be; the two lines will eventually cross. The implication for population growth is that there will inevitably come a time when there is not enough food to go around. At this point, the population growth must be checked by (In his quaint 18th century literary style) Misery or Vice. Misery, being starvation, and Vice, the social disruption of people striving to get more than their share of the available food.
David Ricardo, another amateur economist, friend, admirer, and rival of Malthus, deduced his “iron law of wages” From Malthus’ model. It held that most of humanity was condemned to labor for subsistence wages. Anytime production got a little ahead of the population; the population would quickly exceed the food supply again. For this reason, economics got its name as “the dismal” science. It seemed that economic principles condemned humanity to a miserable existence forever. These ideas have been hotly debated since they were first conceived, but if one looks at human history, at least up until very recently, it seems they were pretty accurate. We still don’t know for sure if Malthusian economics works in the overall human population. Still, we can see that it works in animal populations when an invasive animal species is introduced into a region where there are no natural predators. We know the chaos it produces and the disastrous outcomes for the whole ecosystem, even for the invasive species. Man has reached the point where he has eliminated all his predators and is essentially free from external control.
We do have a sort of natural case of Malthusian economics with humans on Easter Island, an isolated island that is the world’s most remote inhabited place. It appears that the first people arrived at about 900 A.D. The Europeans first discovered the island in 1722. It is estimated that, at its peak, the population of the island had been about 15,000 and that it had been nearly as lush as the Hawaiian Islands when humans first arrived (Jared Diamond, Collapse). At the time of its discovery by Europeans, its population had declined to between 2000 and 3000 people. There was also evidence of widespread starvation and cannibalism (misery?), and the island no longer had any trees. What could the person have been thinking who cut down the last tree on the island (Our burgeoning technology will find a way to replace wood?)? The huge monoliths with faces carved on them, which were quarried, transported, and erected with great effort and for which the island is most famous, had been toppled and many of them broken, indicating the likelihood of some major social upheaval with ferocious conflict (Vice?).
As the Industrial Revolution progressed and gained momentum, world production of goods increased at hitherto unimagined rates. How have we chosen to utilize this great windfall?
Let us imagine for a moment that the coming bounty of the Industrial Revolution was anticipated, and a great international conference was held to decide how to employ the coming increase in production. At the beginning of the meeting, one delegate stood up and spoke, “I know what we should do, we should multiply our population many fold, and let them all continue to live at a subsistence level.” All of the other delegates would say, “What a great idea. Let’s do it.” No rational people would adopt such a policy intentionally, but that is pretty much the approach we have unconsciously and accidentally blundered into as Individual families pursued their own reproductive strategies with no overall plan.
As the industrial revolution took off, the world population rose commensurately. The world population reached 300 million at the time of the Roman Empire from the time people first became human and reached 1 billion in 1804. It hit 2 billion in 1926, a span of just 124 years. It is now over 8 billion; the last billion came in only 12 years.
It is widely believed by those who study population that the earth’s carrying capacity over the long term is one and one-half to 2 billion people. We have heedlessly blundered into a terrible trap over the last 2 1/2 centuries. Most of our 8 billion people still live at or near the subsistence level, but every country has things like television and cell phones. These people see how the developed countries live, and they aspire to live at that same level of consumption. Economists have the concept of the “India man.” It is used as the basic unit of human consumption. An” India man” is the amount of consumption done by an average person in India. The average citizen of each country can be rated by how many India men’s consumption each consumes. The average American consumes about 40 India men. The people of the less developed world will not be willing to quietly sit by and live a marginal existence while we in the developed world carry on our consumptive lifestyle.
In the last century, economic growth has reached such a level that it has elevated the living standard of a sizable proportion of the world’s population above mere subsistence. However, unpredicted strains in the earth’s carrying capacity have begun to arise. The first warning was the publication of Rachel Carson’s book The Silent Spring In 1962, which raised concerns that our population and economic activity are putting a destructive strain on our environment. In the 1970s, the Club of Rome, an organization of concerned scientists, businessmen, and intellectuals, ran computer simulations to see the long-term outcome if the current economic practices continued. An ongoing dispute followed that continues today. Some maintain that the earth’s carrying capacity is far greater than the skeptics thought (drill baby drill). Others maintained that through inventive technologies, we could increase production enough to accommodate a growing population while still maintaining constant or even reducing the strain on our environment. An increasing number of observers maintained that we are poisoning ourselves and damaging our planet. The Club of Rome’s predictions based on their computer simulations and this dispute are to be the subject of the next installment of this series.
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