The Malthusian Dilemma: Population Growth and Resource Scarcity

Background on Thomas Malthus and the Classical Economics Framework

Thomas Malthus was a Church of England Clergyman and a graduate of mathematics who is most associated with contributions to the Classical Economics framework. In his work “An Essay on the Principle of Population”, Malthus postulated that “Population, when unchecked, increases in a geometrical ratio. Subsistence increases only in an arithmetical ratio. A slight acquaintance with numbers will shew the immensity of the first power in comparison of the second.” (Malthus, 1798, p.4). In other words, population growth which is geometric will outstrip growth in production of food (and availability of resources for subsistence) which he determined grew arithmetically resulting in “positive checks” to the population, of higher mortality resulting from famine, disease and war Malthus was talking about the resources required for population subsistence relating to projections he made from the era in which he wrote (late 18th century). His theory was written over 200 years ago, but the idea of human population outstripping its resources is still widely discussed today, for example an article in the Guardian 8 May, 2021 asked the question ‘Are there too many people?’

detailing research and famous ‘wagers’ from economists, demographers and conservation biographers on population versus resource issues.  This essay will argue, that although history shows that Malthus has been shown to be technically wrong’ in his original assertions; 2 centuries later, his premiss that the earth’s population growth may outstrip its resources has not been disproven and the ‘problem’ of feeding an increased population continues to be one discussed and reported upon internationally by nations and supranational agencies such as the United Nations. The context in which he is cited has evolved from the original dilemma to one of sustainable resources, so although ‘wrong’ the underlying dilemma he presented is still discussed today.

Malthus was Technically wrong Malthus was technically wrong about population growth and food supply growth. He suggested that without resource constraints a population would tend to ‘double’ every 25 years (Malthus, 1798) a geometric progression. However, according to data published by Roser et al., (2019), since 1800, when the population was around 900,000 million, it has doubled just 3 times in the last 210 years to 7.2 billion in 2013. He was wrong in his future predictions of population growth, perhaps because he did not foresee the implementation of family planning enabled by the growth in contraceptive choices; or the changes in social conditions which gave rise to the positive choice toward smaller families (though arguably he did foresee that possibility in the notion of ‘moral restraint’ (Malthus, 1803)). However, he was also wrong based on the extrapolation of world population data from his time. Malthus was writing about his time (1798), it was likely he was
working with a paucity of data, and making predictions not based on world population estimates, but extrapolations from localised data from America (Peterson, 1997). As such, Global population had actually taken 200 years to ‘double’ between 1600-1800 (see figure 1 in appendix). On the other hand, a doubling of the population every 70 years, rather than every 25, could be interpreted as a quibble over timeline rather than a positive refutation of the premise that  population growth is exponential, which given the historical data shows it has doubled in a
measurable amount of time, albeit at a much slower rate – it is still essentially an escalating growth rate. One could also argue – that the slower rate of population growth could be attributed to the positive checks on population he identified. There is certainly historically documented population

Malthus was Technically Wrong

reduction from famine, disease and war, for example Europe’s population declined by perhaps 50% in the 14th Century due to weather, economic and disease shocks (Fraser, 2011). [5] Population growth was only one part of the equation, the other was subsistence. Here, Malthus was certainly wrong about growth in subsistence resources. Again, writing from his time, he could not envision and account for the rapid growth in technology – including mechanisation (like tractors), farming methods, chemical fertilisers and genetically engineered crops that constitutes modern farming in the 21st Century. Because of these, food production has been growing at least as fast as population growth – thus far (Sachs, 2008). Indeed the experience of the UK (from where Malthus was writing), was quite the opposite of a food shortage - as the industrial revolution blossomed, and aided by political reforms such as the abolition of the UK Corn Laws in 1846, world trade expanded
massively in agriculture – and saw the development of new low-cost agricultural producers like Argentina and Australia. (The Economist Malthus was therefore likely wrong about the details of the assumptions underlining the two elements of his proposition, however this does not preclude him being ‘right’ about the tendency for population growth to out-strip resources, this will depend on the rates of growth of population in comparison to subsistence (food) resources.

The past does not predict the future The fact that the population growth has not yet outstripped growth in means to subsistence, does
not provide sufficient evidence that it will not happen. We must consider if the future trend of the population growth rate and food growth rate will continue at their current. [8] Actually, the growth in population has not been consistent, it was accelerating, reaching its peak annual growth of 2.1% in 1968 and is now declining (Roser et a., 2019). According to UN projections, total global population will continue to increase (at a slower rate), reaching 8.5 billion by 2030, 9.7 billion by 2050, but peaking at 10.9 billion by 2100 (United Nations, 2019), i.e. increasing until the end of the century then flattening out. However, other demographic studies have been more optimistic about reaching this point earlier (2060-70) due to interventions around the UNs sustainable development goals (see Vollset et al, 2020); Arguably, in line with Malthus’

arguments about “moral restraint” checks on population (albeit a different type of ‘moral restraint’ than the reverend Malthus was referring to). Indeed, it is widely documented that as countries get richer they tend to have falling rates of population growth  However, population growth represents only one half of Malthus’ proposition, that leads us to question if the growth in food production can continue to out-strip population growth - and moreover be sustainable thereafter. Arguably, the growth in food production has been linked to paradigm shifting events; for example, agricultural development post-industrial revolution; growth in new world sources as discussed above. But also, the use of mined phosphorus fertilisers whichm became well established in the mid 19th Century and importantly it is estimated that without this technology humanity could produce only half of the food it can produce today (Faradji & Boer, 2016). Likewise the so-called ‘green revolution’ of the 1960s-70s due to genetic engineering, where Normal Borlaug and his colleagues spent a decade crossing thousands of strains of wheat from  across the globe to develop a high-yielding, disease resistant variety amenable to fertilisation (Biello,
2009). Are the current shifts in capabilities sufficient to grow resources for the projected growth in population – and if not, can we trust that the ingenuity that has led to these paradigm shiftievents will result in another? Borlaug, in his acceptance speech for the Nobel peace prize in 1970,

The Past Does Not Predict the Future

stated that although man was exerting influence to increase food production, a similar effort was not yet applied to human reproduction “The result is that the rate of population increase exceeds the rate of increase in food production in some areas" (Borlaug, 1970), moreover he warned that although the technology had held the tide against hunger, the “ebb tide could soon set in, if webecome complacent” (ibid). [10]
Indeed, the FAO’s 2009 report, ‘How to Feed the World 2050’, a projected world population of 9.1 billion, would necessitate raising food production by 70% to 2050, but that this would require ‘sufficient’ land resources to be turned to agriculture and importantly investments to develop it, with the ‘neglect’ of recent decades in the agricultural research and development needs to be reversed (FAO, 2009). In this respect we cannot conclude that Malthus has for now, and in the future, been proven wrong. 

When Malthus (1798) discussed limitations of the land – what he was describing was a ‘fixed factor’ problem – which, according to neoclassical economics is essentially a ‘diminishing returns’ problem, where the marginal output for increases inputs decreases at an increasing rate when at least one factor is fixed. That diminishing returns problem has thus far been mitigated against, as discussed, by a series of paradigm shifting innovations, from phosphorus fertilizers, to genetic engineering. However, the ensuing ‘modern’ farming techniques developed, are heavily reliant on both water resources and non-renewable resources, such as phosphorus (as discussed above). This begs the question, can food production increase by 70% with current knowledge and resources? Phosphorus is a non-renewable resource which is not just used in agriculture, but pharmaceuticals, consumer products, as catalysts in chemical industrial processes, construction, detergents and even food preservatives. As such scientists have a range of estimates of phosphorus reserves between 35- 400 years, and this could have a catastrophic impact on food production (Faradji & Boer, Moreover, post the ‘green revolution’, agriculture has become more irrigation reliant – it now accounts for at least 70% of human fresh water consumption and by 2050 this will require an additional 15% increase in water withdrawals (Khokhar, 2017). However, in many places in the world fresh water reserves are being depleted, for example satellite studies in India reveal that in many critical regions groundwater is being withdrawn faster than it can be replenished (Rodell, 2009). Other systems show signs of ‘capacity’, such as a report from the secretary general in UNCTAD in 2018 about the critical state of fisheries globally, indicating that “nearly 90% of the world’s marine fish stocks are now fully exploited, overexploited or depleted” (Mukhisa, 2018). The macro statistics also suggest that distribution issues also impact the equation - while there is technically sufficient food production to currently feed the world, not all of the world is fed. The FAO has reported that hunger has been increasing since 2014 and now 9% of the world’s population is hungry (WHO 2020).
The evidence would therefore seem to suggest that capacity for increase in food production is not readily available. However, Faradji & Boer (2016) do also point out that changes in farming techniques could break the cycle of phosphorus mining, reducing the consumption of phosphorus by better use since current  techniques only result in 30% being uptaken by plants, the rest is runoff. Likewise food waste could be reduced – and even an enzyme supplement given to farm animals to help them digest phosphorus, rather than phosphorus heavy growth supplements and develop techniques to reuse the phosphorus from for example sewage.

There are also other ways to access drinking water than reservoirs and aquafers, for example de-salination techniques. Indeed, it can be argued that human ingenuity is key – and is often spurred by urgent need – for example the ‘green revolution’ advances in genetics of crops came at a time when food prices were increasing and there was ‘Global alarm’ at the pickup in population post world war 2 with the Malthusian dilemma very much re-entering the public arena (The Economist, 2008). That actually, there is no limit to human ingenuity (ibid). This is not a universally shared opinion though, Smith (2014) argues that the technical innovation that essentially proved Malthus wrong can no longer be relied upon to keep doing so. However, he does emphasise that other changes in human behaviour can have impact – particularly in respect to food demand. Indeed other economists point to human organisation problems being precipitant in contemporary food security issues, for example economic policy that restricts food exports in response to perceived crises (The Economist, 2008), or the promotion of the use of biofuel and political resistance to the use of genetically engineered crops.