Throughout history, there have been conflicting ideas about the size of populations relative to human wellbeing and whether there is a specific capacity which is optimal. Opinions about the impact of a growing population also vary as while some view a growing population as desirable as it provides the country with greater wealth due to greater output, others believe that population growth is only beneficial up to the optimal point. Whereas, some believe any increase in population will have damaging effects on countries and will ultimately lead to serious problems such as starvation.
Thus, there have been strong contrary views regarding the existence of overpopulation.The Malthusian theory is one of the earliest, most well-known theory exploring the population of a country which considers the relationship between the growth in the supply of food sources and the growth in a country’s population. According to Malthus’s theory, a country is said to be overpopulated if it is at a stage where there are too many people and not a sufficient amount of food available to feed the population.
Malthus states that populations increase geometrically while the food resources available increase only in arithmetic proportions. Therefore, if human population increases in an uncontrolled way without there being any preventive checks, then the number of people in a country would increase at a faster rate than the food supply. Eventually, a point will be reached where the population of a country would reach the limit up to which food sources are able to support it. Further increases in the size of the population would be seriously damaging and lead to a population crash due to issues such as famine. (figure 1)Figure 1 demonstrates the growth of the population as exponential, whereas the food supply is growing in a linear manner. At the point of intersection of the two lines, the Malthusian catastrophe occurs as the population begins to outrun the food supply causing there to be famine in the country. Hence, at this stage of population, population is too high, and the country is overpopulated.Malthus’ ideas were alike to those of some philosophers in early history who believed that the level of human welfare in a country depended on the size of the population. For example, Aristotle, an ancient Greek philosopher and scientist, believed that if the population size became too large, then poverty would occur as a result. This belief came from the fact that land can’t increase as rapidly as reproduction and thus population growth. The philosophers came up with methods of controlling the size of the population, such as colonisation and providing rewards to people for not reproducing. Aristotle considered abortion an appropriate way of regulating the desired population capacity and preventing unnecessary population growth. Likewise, Malthus also appealed for abortion as a method of preventing starvation and maintaining a desirable level of human welfare.Although, the Malthusian theory of population has been critiqued as it lacks validity since Malthus failed to predict that in the future there would be a huge increase in food production as it is a dynamic economy where factors such as technology are constantly changing. Since the industrial revolution, there have been vast improvements in agricultural technology and advancements in farming methods which have rapidly increased the efficiency of food production. Consequently, living standards and welfare have risen despite the growth in the size of the population [Economics, D. and Population, M. (2018)]. Therefore, technological improvements have prevented the Malthusian catastrophe from occurring, and the food supply, despite the size of land being fixed, can meet the population’s needs in a modern economy. [Figure 2 from Mises Circle Features, (2018)]The figure demonstrates the drastic change in per capita income from 1000BC to 2000AD. During periods before the 1800s, the per capita income remained almost constant and followed the Malthusian Trap. Thus, throughout most of history, per capita income didn’t rise significantly and the average living standards in the 18th century in England were not much better than the living standards in the ancient times. However, after the Industrial Revolution began, new, improved technology and farming methods allowed food production to hugely increase which led to a great increase in the size of the population and per capita income. So, the Malthusian Trap failed to continue after the 1800s when we entered the stage of the great divergence. The Industrial revolution was a period of history where there was the transition to new manufacturing processes in the 18th century [Ushistory.org. (2018)]. At this time, Britain became a dynamic economy and innovations in agriculture resulted in increases in the efficiency of food production, thus an increase in the supply of food sources. Methods such as selective breeding and crop rotation are examples of improved mechanisms which were used to achieve this. So, the previous trends before the 1800s failed to continue in the future and a rise in the population was followed by a rise in the production of crops. Therefore, this fails to support Malthus’ theory and implies that in fact there may be no such thing as overpopulation’ if population growth can be supported by improvements in technology.Marx, a German philosopher and economist, also opposed Malthus’ theory of population as he argued that when society is well ordered, increases in the population should instead lead to greater wealth, not hunger and misery like the Malthusian theory suggests. He believed that the reason that this didn’t happen was down to capitalism. Marx was of the view that poverty was not due to increases in the population size but was a result of the capitalist system which failed to provide jobs. Marx stated that the capitalist system failed to provide enough people with jobs, so poverty and unemployment would increase despite the population growth [Maxwell (2018)]. Therefore, Marx believed that the existence of hungry people in Malthus’s day had nothing to do with the earth not being able to provide for them with the given amount of land and level of technological development of society; rather they were hungry because they lived in a class-divided society in which the wealth of the few depended on the poorly-remunerated labour of the many. Therefore, Poverty and hunger were a product of social relations, not overpopulation.On the other hand, it has been argued by some thatinstead of focusing on the effect of population size on the food supply of a country, we should concentrate on the impacts the capacity of the population has on the total output and wealth of a country. This idea led to the optimum theory of population being introduced. Some believe that food supply is not an issue as we can simply import food from other countries in exchange for other goods produced. The concept of countries having a point of optimum population is explained by Cannon’s theory of population which explores the relationship between a country’s population and the resulting per capita income. According to Cannon’s theory, the optimum population is the population size that produces maximum returns in the form of income[Economics Discussion. (2018)]. The optimum population size is when there is the most efficient use of the country’s available resources and yields maximum per capita income. Any deviation above or below the optimum size will cause there to be a decrease in the income per person. Hence, when the size of the population is higher or lower than the optimum level, it is said to be over-populated or under-populated. (figure 3)Figure 3 shows that the point of optimum population is at the peak of the curve, at point B, where the per capita income is at its highest. At any points to the left of the maximum point B, the per capita income is lower, implying that the country is underpopulated since the capacity can be increased until it reaches the optimum capacity which is where resources are efficiently and fully utilised by the country. So, a country is believed to be underpopulated when an expansion of the number of people in the country is met with a consequent increase in the per capita income. When the country is underpopulated, there is a shortage in the supply of labour so there aren’t enough workers to exploit all the available resources with maximum efficiency, resulting in a decrease in the total output produced and a reduction in per capita income. Similarly, there is also a reduction in per capita income at points to the right of the optimal point, such as point C. This demonstrates that a rise in the population above the maximum point B leads to a decline in returns. This decline occurs since the labour force becomes too large for production to be efficient and yield maximum output and per capita income. For example, when there are too many workers, it can get overcrowded, causing workers to produce output less efficiently. Therefore, points above the optimum point of population are at the stage of overpopulation where there is less per capita income.The law of diminishing returns is used to explain Cannon’s theory of population. The law states that as labour, a variable factor of production, is added to land and capital, the fixed factors of production, total and marginal output will at first begin to increase until the maximum output is achieved[Encyclopaedia Britannica, (2018)]. Eventually, as additional units of labour are added, the total output and marginal product of labour will fall. When the size of the population increases, there is an increase in the size of the labour force so the number of workers in the country is greater. This increases the country’s total output and per capita income up to a certain point. After this point has been reached, problems such as more frequent breakdowns due to excessive utilisation of capital, difficulties monitoring the large number of workers, and overcrowding of work spaces will inevitably arise. As a result, marginal returns to each extra unit of labour becomes increasingly smaller and eventually becomes negative, causing there to be reduced per capita income. Therefore, when there is over-population in a country, the output yielded from each extra unit of labour will fall and average product of labour will also diminish. The theory behind this law describes the concave shape of the curve in figure 3 as the curve starts as upwards then once the highest peak is reached, it slopes downwards.In order for this theory to hold, there are two assumptions that have been made. One is that as the population grows, the proportion of the number of workers in the population to total population remains the same. In addition, the theory assumes that the stock of natural resources, technology and capital also stay the same [Economics Discussion, (2018)]. However, the second assumption caused there to be criticism of the theory as it reduces the practicality of the theory because in a real world, factors such as technology and the availability of capital are constantly changing and impacting the economy. Because these factors are not constant like the theory assumes, it makes it impossible for us to determine a fixed optimum size of the population as it isn’t a constant point. For example, if developments are made which allow there to be more advanced methods and production techniques, the average product of labour and per capita income might increase, making the optimum point higher. Similarly, if the availability of capital or natural resources in a country increases, this will also lead to the optimum point being higher than it previously was. Evidently, this shows that the optimum size of a population at a certain point in time may become less than the optimum at a later period, meaning there is no fixed desirable population capacity that can be determined. (figure 4)Figure 4 demonstrates a vertical shift upwards in the average product of labour curve due to changes in the country such as developments in technology. The curve moves up from AP to AP1 and the optimum level, where per capita income is greatest, rises from point L to point L1. Point L1 shows the maximum per capita income at the new optimum level of population at P1. Therefore, the optimum level isn’t a constant fixed point, but is movable as factors in the economy are constantly changing, so the optimum level varies, depending on such factors. This creates difficulty in determining at what specific capacity is always the optimum population for a country.While both Malthus’s and Cannon’s theories acknowledge the existence of a point of over-population, the optimum theory of population is considered as an improved theory of the Malthusian theory. One reason for this is because Malthus’s theory is seen as mostly theoretical and lacks practicality. This is because he considered any increase in the size of the population to be detrimental to the country as he believed it would inevitably cause there to be suffering and starvation as a result of a lack of natural resources being able to provide for and support the population’s needs. Conversely, the optimum theory of population is regarded as a more realistic approach since it appreciates that an increase in the population size up to a certain point is not only beneficial but is also necessary for the maximum utilisation of a country’s natural resources to be met.Although there are different views about the optimum size of populations and what capacity this occurs at, the two main theories: Malthus’s theory and the optimum theory of population, both state that there is a certain point which is the optimal size of population. However, the exact point at which the population is said to be at its optimum has not yet been determined due to the fact that it is not a fixed point because factors are always changing in an economy. Therefore, there is an optimum size for populations where there is the most efficient utilisation of a country’s resources, yielding maximum returns.