It is paradoxical that one of the most popular, powerful and enduring theories in economics has been proven wrong generation after generation. But then, there are few more captivating ideas than that the human race is expanding and exploiting the planet’s resources so fast that it is heading for inevitable self-annihilation. Behold the Malthusian trap.
You are probably familiar from your biology lessons with those microscopic images of cells multiplying. You start with a couple of cells, each of which divide to form another pair; they multiply rapidly, second by second spreading out to the corners of the Petri dish until, eventually, they have filled it to its very edge and there is no more room left. What happens then?
Now take humans. They also reproduce at an exponential rate. Might we not be expanding too fast to be able to sustain ourselves? Two centuries ago, English economist Thomas Malthus was convinced we were. Humans were growing much faster than were their sources of food, he calculated. More specifically, he came up with the idea that the human population was rising geometrically (i.e. by multiples—2, 4, 8, 16, 32 …) while the food available to them was growing arithmetically (i.e. by addition—2, 4, 6, 8 …).
As Malthus himself said in his 1798 Essay on the Principle of Population, man needs food in order to survive, and man is multiplying at a rapid rate. He concluded:
I say that the power of population is indefinitely greater than the power in the earth to produce subsistence for man. Population, when unchecked, increases in a geometrical ratio. Subsistence only increases in an arithmetical ratio. A slight acquaintance with the numbers will show the immensity of the first power in comparison with the second.
In his eyes, the human race was heading for an inevitable crunch. Unless it voluntarily cut its birth rate (which he thought was inconceivable), the human population would suffer one of three unpalatable checks imposed by nature to keep it at certain sustainable limits: famine, disease or war. People would be unable to eat, succumb to some plague or another, or fight each other for increasingly scarce resources.
You can see why the Malthusian trap is often referred to as the Malthusian catastrophe or dilemma. This profound problem is still used today by various experts who advocate the necessity of controlling the size of the world population. It is an idea which has been adopted by many environmental movements to illustrate the unsustainability of the human race.
“Malthus has been buried many times, and Malthusian scarcity with him. But as Garrett Hardin remarked, anyone who has to be reburied so often cannot be entirely dead.”
Herman E. Daly, US economist
Problems with the theory But Malthus was wrong. Since he put pen to paper, the global population, which he thought was reaching a natural peak, has grown from 980 million to 6.5 billion. It is projected to balloon to more than 9 billion by 2050. Yet the majority of people on the planet are better fed, more healthy and longer-lived than ever before. Malthus was wrong in two areas:
Thomas Robert Malthus 1766–1834
Despite being the man who inspired Thomas Carlyle’s dismissal of economics as “the dismal science,” Thomas Malthus was in fact a highly popular, entertaining character, sociable and well regarded, despite his gloomy ideas. He was born into a wealthy family with an intellectual bent—indeed his father was an acquaintance of the philosophers David Hume and Jean-Jacques Rousseau—and spent most of his life either studying or teaching, bar a period as an Anglican curate. Economics was seen as so protean a subject that it was not recognized in its own right by most universities, so Malthus studied and later taught mathematics at Jesus College, Cambridge. However, it is a testament to the growing popularity of economics that in the early 19th century he became the world’s first ever economics professor, teaching the subject at the East India Company College (now known as Haileybury) in Hertfordshire. And, in 1818, in a clear sign of the field’s importance, Malthus became a Fellow of the Royal Society, in recognition of his pioneering work in economics.
Economic historian Gregory Clark argues in his controversial book A Farewell to Alms that until 1790 man was indeed stuck in a Malthusian trap, but, due to a combination of factors thereafter—including the ill-fortune of the poorest to be killed off by disease, the need for them to be replaced by children of the upper and middle classes (“downward social mobility”) and the proclivity of these classes to work harder—England escaped. He asserts that many parts of the world, having still not undergone this experience, remain stuck in the trap.
However, what was certainly not wrong was the theory underlying Malthusianism: the law of diminishing returns. It has important lessons for businesses. Take a small farm or factory. The boss decides to add one extra member of staff each week. To start with, each new employee causes a big jump in production. Some weeks later, though, there will come a point when each new worker makes that little bit less difference than the previous one. There is only so much difference an extra pair of hands can make when there is a finite number of fields or machines with which to work.
Apocalypse where? The way most of what we now call the Western world (Europe, the US, Japan and a handful of other advanced economies) broke out of the Malthusian trap was by raising agricultural productivity while at the same time, people as they grew wealthier had fewer children. This, alongside the invention of new technologies, helped fuel the Industrial Revolution, and eventually catapulted levels of wealth and health ever higher. Unfortunately, there are parts of the world which are still stuck in the trap.
In many sub-Saharan African countries, the land produces so little food that the vast majority of people have to work in subsistence farming. When they boost agricultural output by using new technologies to grow more crops, their populations balloon, and the famines that often follow in years of bad harvests keep the population from growing and becoming richer in the ensuing years.
Apocalypse when? Neo-Malthusians argue that although human ingenuity has managed to delay the catastrophe for a couple of centuries, we are now on the brink of another crunch. They contend that although Malthus’s arguments revolved around food, one could just as easily insert oil and energy sources as being the chief “means of man’s support.” With the point of “peak oil” close at hand, or perhaps having passed, the global population will soon reach unsustainable levels. Whether the technological advances or population restraint that prevented Malthus from being proved right hitherto will apply this time remains to be seen.
the condensed idea
Beware relentless rises in population
| timeline | |
|---|---|
| 1776 | The Wealth of Nations by Adam Smith is published |
| 1798 | Essay on the Principle of Population by Thomas Robert Malthus is published |
| 1805 | Malthus becomes professor of economics at Haileybury |
| 1859 | On the Origin of Species by Charles Darwin—and influenced by Malthus’s ideas—is published |