Romola Davenport

‘Malthusianism’ is widely used to describe the belief that (1) human populations grow faster than the resources on which they depend, and (2) that the main way in which population is prevented from outstripping resources is by the ‘positive check’ of mortality, resulting in the most extreme circumstances in ‘Malthusian crises’ (famine and war).  

These ideas have been profoundly influential and have underpinned major 20th century population policies, from China’s One Child policy to the family planning programmes promoted by the Rockefeller Foundation and the Club of Rome. And while overt population control policies have been largely replaced since the 1990s by ‘reproductive health’ campaigns, concern about population size and growth rates have resurged again in recent debates about global warming.  

But what did Malthus actually say?

Thomas Malthus (1766-1834) is best known, or notorious, for his ‘Essay on the Principle of Population’. Although Malthus produced six editions of his Essay, most people are familiar only with the contents and argument of the first edition, published in 1798.  

This first edition was a slim volume that set out the central logic of Malthus’s argument, and it is the most accessible of the editions because it is written very clearly, without many examples or evidence. His argument is simple and compelling:  

1. Human populations are capable of extremely rapid increase;
2. Resources are limited.

Before the widespread use of fossil fuels, humans were largely limited to the produce of the land. They depended on the soil for food, clothing, fuel and materials. So if they wanted to increase the amount of animal power they used in agriculture, to achieve deeper ploughing and to increase yields, then they needed to devote some crop land to fodder for the animals. If they wanted to use fuel for industry, then they had to devote more land to wood production instead of food.

Increases in productivity were possible, but there were limits, and as these limits were approached then the law of diminishing returns kicked in. In the case of agricultural land this meant that the best land tended to be exploited first. As more marginal lands were brought under cultivation then these generally required higher inputs for lower yields.    

Malthus’ first Essay has been hugely influential, and its logic is still widely held today. However Malthus wrote this first version as a polemical attack on William Godwin, who had produced a tract on the perfectibility of mankind. Malthus argued instead that humans were trapped by the ‘iron laws of population’ into almost universal poverty, because they could not restrain their population sufficiently to allow living standards to rise much above subsistence for very long. 

The first edition of the Essay included almost no evidence for Malthus’ claims. However Malthus himself was committed to empiricism, or an evidence-based knowledge. In his subsequent editions of the Essay he substantially modified his arguments and came to a much more optimistic conclusion regarding the possibility of rises in living standards, although he never renounced his central thesis. 

Modified arguments

After writing the first edition of his Essay, Malthus was subsequently influenced by two main sources of information. The first was the inception of the English censuses, from 1801. When Malthus wrote his first Essay there was heated debate about the size of the English population, and whether it was growing or shrinking. The first census of 1801 revealed that it was much larger than most commentators had thought – 8.7 million. And subsequent censuses, conducted at ten-year intervals, revealed that the population was in fact growing very rapidly.

Malthus was surprised by this, because he had assumed and argued that in long-settled lands, such as European countries, the population would long since have exploited most available land for agriculture and other activities, and the population would be in a rough equilibrium with resources.  

In fact, Malthus was born at about the last point where that argument could ever have been made for England. Having stagnated somewhere below five and a half million for a century, similar to its estimated medieval maximum, the English population began to grow rapidly after 1750, to nearly 9 million by the first census, and over 13 million by the time Malthus died in 1834 (see Figure 1 below). The English population has continued to grow, albeit more slowly, ever since, and the global population has achieved much higher rates of growth, without strong evidence of Malthusian positive mechanisms operating to check the population.  

It is evident that the stagnation of population c.1650-1740 was not due to resource constraints. Urbanisation increased over this period, indicating economic growth, and real wages rose. Malthus regarded urbanisation as a positive check on population (through higher mortality in towns), however this kind of check was clearly unrelated to resource shortages.

Given the evidence for England (and for a number of other European societies with relatively robust census data that demonstrated sustained population growth), Malthus was compelled to modify his argument. In subsequent editions of his Essay he acknowledged the potential for population and resources to ratchet upwards for limited periods without severe checks, under certain very propitious conditions that he thought obtained in parts of western Europe.  

Checks

The second source of evidence Malthus drew on when modifying his arguments were collections of ethnographic and historical evidence that were becoming widely available as part of the huge expansion of European colonisation and trade in the 18th century. These sources (still in Jesus College library in Cambridge) alerted him to the huge diversity of cultural practices that mediated the interactions between individuals, households, communities and states on the one hand, and resources on the other. These practices included infanticide, which was an acceptable means in many societies by which to shape the size and composition of families, and which is echoed in the popularity of sex-selective abortion across much of central, south and east Asia.  

Together these sources of evidence led Malthus to a much more positive conclusion than he had expounded in the first edition of his Essay. He came to recognise that the population of England and of some other European societies was not regulated chiefly by mortality, but by what he termed ‘preventive checks’. These checks operated to prevent births and therefore averted the need for high mortality to keep population in balance with resources.

‘Moral’ preventive checks operated through cultural norms, for instance those that dissuaded individuals from marrying and having children if by so doing they would reduce their standard of living. In theory this type of preventive check made it possible for populations to achieve lasting improvements in per capita consumption by allowing production to outpace population growth.  

Interestingly, Malthus argued that this preventive check would operate not only on poor labourers but also on farmers, gentlemen and ‘some men… even in the highest rank’, since a wealthy gentleman would not want to expose his wife to poorer conditions than she had been raised to expect, just as the labourer would not want to find himself unable to feed his children. Women, on the other hand, appear to have had no agency in Malthus’ world view.    

What Malthus did not appreciate, but which anthropological demographers have since highlighted, is that small-scale societies and family units often faced the opposite, decidedly non-Malthusian problem of population collapse, because they were very vulnerable to ecological shocks or to stochastic variations in fertility and in the sex of children. This problem is evident for instance in cultural practices such as adoption, which smooth out variations in fertility between families.  

Malthus’ research also led him to identify the importance of the levels at which checks operated. He argued that where individuals had more personal freedom and political liberty, then they were both more able and more inclined to act in their self-interest by restraining their fertility. He recognised the importance of cultural norms in influencing how individuals, families and societies shaped their group sizes, and in determining what was considered to be an acceptable standard of living.  

Malthus also expressed strong opinions on the roles that governments could play. In the English case he was a strong opponent of the English welfare system, known as the poor laws. He regarded the poor laws, at least in their more generous manifestations, as encouraging early and improvident marriage because they provided a safety net when families could not support themselves.  

However, while Malthus was generally hostile to the operation of the poor laws, he was compelled by his empiricism to acknowledge the important role they had played in preventing famine in England.  

By 1826, Malthus’ Essay had passed through six editions and had grown from roughly 60,000 words to 290,000. Later editions lacked the elegant simplicity and force of the first edition. At times his argument appeared strained or self-contradictory. Most problematically, Malthus did not succeed in explaining clearly how a population such as England’s, long-settled, at peace and with substantial political liberties (by contemporary standards), could continue to grow so rapidly and without major rises in mortality. 

The present day

This puzzle has continued to afflict modern exponents of Malthusian theory. World population has grown from about 1 billion to 8 billion over the last two centuries. In that time, famines have largely disappeared (except those caused by war), and per capita consumption has increased many-fold.  

It is often argued nonetheless that Malthus was right, and that we have simply succeeded with technologies in pushing the ceiling of global population-carrying capacity to higher limits, limits that we are now approaching.  

Whether we are close to any such Malthusian limit may however never be tested, because the global population is expected to begin shrinking within this century. Over half the world’s population now lives in states or countries with below-replacement level fertility. China’s population of 1.4 billion is shrinking, together with the populations of Japan, Greece, Italy, and much of eastern Europe. Malthus would not have approved of the means by which these fertility reductions have been achieved (by contraception and abortion rather than ‘moral restraint’). However, the prospect of a peaceful end to the 20th century ‘population explosion’ must be regarded as a triumph of the preventive over the positive check. 

Since the late 19th century, reproduction has become progressively unhitched from sex and marriage, but also from resources. Malthus’s original argument was that any increase in resource availability would elicit an increase in population, which would act to bring population and resources back into some culturally-determined equilibrium. Instead, what has happened over the 20th century is that per capita wealth and consumption have become negatively associated with population growth and birth rates. The small minority of populations with high fertility rates have very low average incomes, and account for negligible fractions of global greenhouse gas emissions (either per capita – Figure 2 or absolutely – Figure 3). 

 

As Figure 3 shows, the vast majority of the total emissions is due to populations with modest fertility (under 3 children per woman), with over half of all emissions occurring in societies with below replacement level fertility rates (conventionally, less than 2.1 children per woman). Populations with high fertility (4-8 children per woman) contribute almost nothing to the global burden of greenhouse gases.

Conclusion

What are the implications of Figures 2 and 3 for global warming and for the devastation of natural environments that has accompanied economic development? Those concerned about population growth often describe population as ‘a multiplier’, and worry that the very high growth rates still evident in some mainly sub-Saharan African populations will cause problems in the future as these populations grow rich. However, at present there are few examples of populations that transitioned to low fertility without substantial increases in per capita greenhouse gas emissions (used here as a proxy for environmental impacts). This means that ‘population control’ may not in itself achieve the reductions in environmental impacts that its advocates espouse, if declines in fertility are accompanied by massive rises in consumption.  

Therefore, it may be more important to focus on ways to enhance human development and wellbeing that don’t result in very high per capita consumption and waste – that is, perhaps to be more like Costa Rica, and less like the USA.  

Further reading

• Wrigley, E. A., ‘Corn and crisis: Malthus on the high price of provisions’, Population and Development Review 25:1 (1999), 121–28. https://www.jstor.org/stable/172374 
• Wrigley, E. A., ‘Elegance and experience: Malthus at the bar of history’, in D. Coleman and R. Schofield, eds., The state of population theory. Forward from Malthus (Oxford, 1986), pp. 46-64. 
• Wrigley, E.A., and Souden, D., The works of Thomas Malthus (London, 1986), vols 1-3.  

Tags: demography, famine, fertility, malthus, mortality, poor laws, population size

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