Demographic growth, since earlier times, has always been a topic of debate and reflection, always establishing a discussion between the availability of resources, number of inhabitants and socioeconomic development, see below the main demographic theories .
1. The Malthusian Theory
Thomas Robert Malthus was the name of a British pastor and economist, creator of the first great postulate on population growth and its possible consequences.
In the eighteenth century he wrote Essays on Principles of Population, in two volumes, in which he expressed his great concern at the accelerated population growth and its damaging consequences for society.
According to Malthus’s demographic theory, if there were no wars or epidemics, the world population would double, on average, every 25 years, that is to say that the population would follow the rhythm of a geometric progression . At the same time, food production would not follow the same pattern, precisely because it has a limitation: the availability of land. This means that it would grow according to an arithmetic progression .
According to his prediction, there would be a time when the lack of land to grow food for an increasingly large population would bring hunger, malnutrition, pests and epidemics, forcibly reducing the number of inhabitants so that there would again be a balance between the availability of land and population.
Malthus, by his religious background, proposed that families should have only children if they had land to support them and that sex, between husband and wife, was only carried out with the intention of procreating.
It is evident that this postulate took into account the sociocultural conditions of eighteenth-century England, when the rate of population growth was high and the field had not yet modernized. With industrial development, rural areas began to produce more with less manpower, and cities provoked more and more changes in the behavior of society; among them family planning.
Therefore, the forecast of doubling of the population every 25 years was not confirmed, as well as the lack of food due to the lack of space for cultivation also, since the technology applied to the agricultural production increased considerably the production of foods.
2. The Neo-Malthusian Theory
Well after the Malthusian demographic theory, as early as the twentieth century, the world was caught up in the two great world wars. At the end of the Second World War, as a result of the agreements between allied countries, the United Nations (United Nations).
Its main goal was to avoid new conflicts like the one that had just happened and for that it was necessary to minimize the brutal differences between the countries in the economic and social plan.
The great problem became the justification that could be given for the vast majority of the world’s population to live in subhuman conditions and especially what could be done to counteract this situation.
It was in this context that the Neo-Malthusian Thesis spread, trying to explain the occurrence of technological, economic and social backwardness in the poor countries as a whole. Through it, neo-Malthusians said that in the underdeveloped countries, the main factor responsible for the demographic explosion was the excessive population growth, since the large number of young people demands of their countries large investments in health and education, without having a counterpart in production , since it is theoretically an inactive population. At the same time, resources would be lacking for investments in productive sectors such as agriculture, livestock and industry.
Another argument used by them is that the larger the population in a country, the lower the per capita income , which would prevent an improvement in the standard of living of its inhabitants. The name referring to Malthus is justified by the fact that both point to demographic growth as the cause of misery and poverty. Therefore, it is an antinatalist demographic theory.
3. The Reformist Theory
In response to the Neo-Malthusian theory, some scholars of the underdeveloped world have created a theory called the Reformist , for proposing just the opposite of what the neo-Malthusians proposed.
Reformists say that high population growth is a consequence and not the cause of underdevelopment. In these countries, the lack of investments in the social and infrastructure areas has created large pockets of poverty, with a poor population, unable to overcome the situation in which they are.
For them, there is a natural tendency to reduce birth rates as living conditions improve. As families gain access to better education, health care, information, they tend to have fewer children.
For this reason, urbanization plays a very important role because it represents, at worst, access to the minimum public services, which is not always accessible in rural areas.
4. The Demographic Transition Theory
In the year 1929, Warren Thompson proposed the concept of demographic transition as a way of challenging Malthusian theory. In this way, the idea of an accelerated growth of the world population was replaced by periodic oscillations, that is, times of greater and lesser vegetative growth .
The following image presents four stages of vegetative growth:
The first stage, occurring in agricultural societies and exporters of raw materials, has very high birth and death rates.
The second stage already shows high birth rates, but with a sharp decline in mortality, which is due to improved basic sanitation, antibiotics and technological development, albeit at an early stage.
The third stage , in which Brazil finds itself, shows a significant reduction in the birth rate, justified by the urban-industrial development, by the greater participation of women in the labor market, by late marriages and by the adoption of contraceptive methods.
The fourth stage , present in the most developed nations of the globe, has very low birth rates and mortality, with negative growth occurring in some cases. Some European countries, for example Germany, France and Sweden, offer financial compensation for couples to have more children. These stimuli focus on increasing birth rates and vegetative growth.
If high birth rates, such as those in African and Southeast Asian countries, can pose serious problems for poor countries, their drastic reduction with negative vegetative growth also causes problems such as the lack of young workforce and excessive spending on the elderly.