Malthusian Theory

Assumptions of Malthusian Theory of Population

In designing his theory, Malthus made a series of assumptions which are presented below:

1. Food is necessary for life.

2. Food production increases arithmetically (1,2,3,4,5 etc.)

3. Population, on the other hand, increases geometrically or exponentially (1,2,4,8,16, etc.).

4. Passion between men and women is necessary and will continue unchanged.

5. Population is limited by food—population increases when food increases, unless prevented by some checks.

Using these assumptions, Malthus posited that the food supply would eventually be unable to keep up with population growth as the latter would double in 25 years, while the former would not. This is because the country could only grow a finite amount of food, based on land availability. As a result, in an attempt for the system to correct itself and return to a state of equilibrium, there would be checks. These checks would either be positive (natural) or negative (preventive).

Preventative checks come from man. With more children, it is likely that the standard of living would decline and the children will be exposed to poverty. Therefore, in an effort to avoid the aforementioned, people would limit their family size. Negative checks include birth control, abstinence, or postponing marriage. This would reduce fertility rates and birth rates and also prevent the potentially disastrous impacts of positive checks.

According to Malthus, mankind should use preventative checks to save themselves from the misery that would come from a lack of food. If not effectively implemented, then positive checks would kick in to correct the situation.

These checks bringing down the population to a more sustainable level is known as the Malthusian catastrophe.^3,4

Fig. 2 - Graphical representation of Malthusian theory

Limitations of the Malthusian Population Theory

The following are some, not all, of the limitations of Malthus' theory.

Malthus could not foresee the improvement of technology in agriculture. These include the use of fertilizers, better seeds, and advancement machinery, among others. In fact, the Green Revolution in places such as India has actually caused the rate of food production to surpass the population growth rate. Hence, population growth does not always exceed food supply.

The Malthusian theory was limited to England and based on that country's unavailability of land for agricultural purposes and the resultant low agricultural yields.

At the time, Malthus looked at the limited availability of land as the constraining factor of food production. However, as a result of globalization, food is traded across borders, which results in an increase in its availability in countries.

Malthus neglected to show how he calculated the arithmetic growth rate of food and the geometric growth rate of the population. Therefore, it has been pointed out that empirical data shows that growth rates are not consistent with Malthus' predictions.

It has been asserted that Malthus looked at the wrong relationship. The relationship between population and food supply is a weak one and the correct relationship is that between population and a country's wealth. It stands to reason that if a country has enough material wealth, even if it cannot grow enough food domestically to feed its population, it can feed them by importing food. E.g. Great Britain imports a large proportion of its food.

Malthus linked population growth only to birth rates, whereas globally, the population has grown due to a decline in death rates, which has been realized as a result of advances in the medical field.

Importance of Malthusian Theory of Population

Although it had its limitations and criticisms, Malthus' theory was important for a variety of reasons. It revolutionalized the way in which population growth was conceptualized in that it acknowledged that it was related to people's welfare. Malthus' theory also forced people to consider the effects of food supply and the availability of food on the population and paved the way for other theories of population growth, including Esther Boserup's, which was largely considered anti-Malthusian.

In spite of its largely pessimistic outlook, the Malthusian theory educated people about the negative impacts of overpopulation and motivated them to take steps to prevent it. In this way, it impacted public policies. India, for example, was one of the first countries to adopt family planning at the state level. In addition, the theory influenced declining populations, particularly in Europe, out of the fear of the Malthus "doom and gloom" predictions becoming a reality. Furthermore, it has been suggested that it is the legacy of Malthus that has influenced the use of contraceptives to this day. Moreover, Malthus' principles have been incorporated into the theories of other researchers, such as Darwin and Pigou.

Fig. 3 - Family planning was so important in India that messaging was even included on the country's stamps

Malthusian Theory Example

As an example of Malthus' theory, we will look at rice production and population growth in Nigeria. Between 1960-2015, local rice production increased from an average of 268,840 thousand metric tons from 1960-1969 to an average of 2,678,900 thousand metric tons from 2010-2015. At the same time, the demand for rice, which can be used as a proxy for population growth, increased from an average of 300,569 thousand metric tons to an average of 3,399,000 metric tons. While the population here has not grown exponentially, growth has been significant. Therefore, the data support Malthus' assumption that the population grows faster than food production.

As the trend continued, there was a so-called "point of crisis" which can be likened to the Malthusian catastrophe, where the country faced misery, characterized by food insecurity, epidemics, conflicts, and poverty. Of particular concern was the HIV/AIDS epidemic which can be likened to a positive check as it took a lot of lives.

Despite the country's vast resources, the rate of poverty is quite high in Nigeria. This also fits in with Malthus' assertion that increasing population would reduce the standard of living and cause poverty. Additionally, advancements in birth control and other negative check methods have not been widely accepted in Nigeria.

One thing that Malthus didn't account for in his model was the growth in the importation of food as well as the delivery of aid from the developed world and the impact this would have on food availability. Nigeria is a net food importer to feed its population. As a result of all of the aforementioned, it can be concluded that some of Malthus' predictions do apply to Nigeria.^6,7