Yves Charbit - Demographic Dynamics and Development

If we add to the main countries that completed their demographic transition in 2019 (groups 1 and 2), those of the third group (ending in 2030), this set comprises 78% of 2019’s world population (6.1 billion). But this will significantly decrease: by 2100, it will bring together 5.3 billion inhabitants, or 48% of the world population (estimates and medium-variant) (United Nations 2019a). Indeed, the countries which are currently completing their demographic transition will experience a modest population growth, with an older age structure.

However, the population of the main countries where the demographic transition is still “awaiting completion” (groups 4, 5 and 6), which reached 1.3 billion and 16% of the world’s population in 2019, will rise to 3.5 billion inhabitants by 2100 and its proportion will double (32%). Its population growth will be high due to the gap between the decline in mortality and the decline in birth rates, and a young age structure.

The demographic transition started in the mid-18th century in Europe, prompting two centuries of extraordinary progress reducing the mortality rate, because of the control of epidemics and famine. In France, between 1780 and 1840, life expectancy rose from under 30 to over 40 years of age, and from 1880 to 1940, from 43 to almost 60 years. Infant mortality also fell sharply. Advances in mortality did not take place in all European countries at the same time, or at the same pace. They were interrupted by wars (War of 1870, First World War) and the flu of 1918. Medical discoveries, in particular those of Pasteur on the microbial origin of infectious diseases, health progress and a rise in the standard of living, significantly contributed to reducing epidemics and food shortage (Vallin 2003, pp. 9–14). In addition, the increase in life expectancy continued to soar, reaching over 80 years between 2015–2020 (in Australia, Canada, South Korea, Europe, Japan, Singapore, etc.). In 2019, at a global level, life expectancy for both sexes was 72.3 years: in developed countries, it was 79.2 years, and 72 years in developing countries (United Nations 2019a, Table A.28).

After 1870, the decline in fertility in Europe started later than that of mortality, falling from almost five children to around two or three children per woman on the eve of the Second World War. Only France started limiting births in the mid-18th century, more than a century before other European countries (Festy 1979). The gap between the dates of the beginning of the decline in mortality and that in fertility was responsible for a strong population growth. Thus, the population of England and Wales increased from 6.5 million in 1750 to 42 million in the early 1940s (Vallin 2003, p. 27).

In the mid-20th century, the demographic transition spread to Asia and Latin America, with mortality declining after 1950, followed by fertility circa 1970 (Chesnais 1986a). The decrease in mortality was further accelerated by the effectiveness of health policies resulting from previous experiences in developed countries (Omran 1971). For four decades, between 1940 and 1990, the birth rate greatly exceeded the crude death rate, leading to strong population growth, higher than 2% per year. This figure had never been reached in Europe or in Japan (Chesnais 2002, p. 458). Finally, during the second half of the 20th century, the decline in fertility became widespread. Contrary to what happened in Europe, “the explosion of the Third World” (Vallin 2003, p. 60) resulted in the implementation of birth control policies, thus rapidly reducing fertility. As Vallin wrote, “there are few cases when one can say that the introduction of a birth control program is the main factor underlying a desired reduction in fertility” (Vallin 2011, p. 344). But he rightly emphasized that access is made easier, for couples and for women who wish to limit their births, when such programs exist (Vallin 2011, p. 344).

To explain the decline in mortality in Europe since the end of the 18th century, Abdel Omran (1971) proposed the theory of epidemiological transition, or the passage from an old mortality regime (the “age of pestilence and famine”), through a transition period of a “decline in pandemics”, to finally reach the last age of “degenerative” and “societal” diseases (Omran 1998). Then appeared the more general concept of “health transition” (Meslé and Vallin 2002). During this period, medical advances for reducing infectious and cardiovascular diseases were accompanied by the development of food, agriculture and education, as well as an improvement in the living standards, the establishment of a sanitation infrastructure (drinking water, sewers) and the development of health systems. But, within these dimensions, inequalities have widened, because the entire population does not have equal access to them (Meslé et al . 2011, p. 484).

In Europe, the delays in the age for marriage 10accompanied the secular decline in fertility, in the absence of effective contraception methods for couples. In 1840, Festy made a distinction between countries with late marriages, over the age of 27 – Scandinavian countries (Denmark, Norway, Sweden), Belgium, the Netherlands, Switzerland – and countries with early marriages, under the age of 26 – Finland, Great Britain, Germany, Austria, Southern Europe (Spain, Italy and Portugal) and North America (Festy 1979, p. 28). He showed the complex relationship between late marriage, low fertility, breastfeeding habits and differences in fecundity between the rich and the poor in 1870 (Festy 1979, p. 42). In addition, “intermediate fertility variables”, which are biological, social and economic as well as cultural, work together in the reduction of fertility (Davis and Blake 1956). Bongaarts calculated that they could be reduced to four determining variables, which alone explain the majority of changes in fertility: the age of the first union, the duration of breastfeeding, the use of contraception methods and abortion (Bongaarts 1978). In Asian and Latin American countries, modern contraception and abortion have played a predominant role in birth limitation, because “the contraceptive revolution” reached all the regions in the world (Leridon and Toulemon 2002). In Africa, the duration of prolonged breastfeeding has a reducing effect on the number of children per couple (Tabutin and Schoumaker 2004).

Coale grouped the main macrosocial causes that explain fertility changes in the RWA model (Coale 1973):

– a first factor is the reasoned choice to give birth to a child. The advantages and disadvantages of an additional birth should be accepted by couples. This factor is called readiness (R). It determines the beginning of controlled fertility, in particular due to economic reasons;

– a second factor is the perception that low fertility is socially and economically beneficial for mothers and fathers. This factor is called willingness (W). It points to the social legitimacy of fertility control within families and a normative/cultural change in values;

– the third factor is the availability of birth control methods and their effective use. This factor is called ability (A). It depends on the diffusion of contraception methods, birth control infrastructure, and health and sanitation policies.

According to Coale, the main factors for the fertility transition to come about must simultaneously be economic, cultural and institutional. The three RWA preconditions act mutually, and if only one is lacking, the decline in fertility will not take place (Coale 1973; Lesthaeghe and Vanderhoeft 2001). As not all individuals change their behavior at the same time, and only pioneer groups adopt them, the diffusion toward the rest of the population is conveyed by means of “social interactions” (Bongaarts and Cotts Watkins 1996). But it can be slowed down or accelerated depending on the cultural, religious and linguistic standards of each region 11. Bourgeois-Pichat (1976) stressed the importance of group effects: “Of course, the couple decides, but they do so according to the social criteria and cultural heritage which, although quickly driven out, paradoxically maintain their rights” (p. 1077).