(Published - 30 July 2020)
WHO: This dramatic growth has been driven largely by increasing numbers of people surviving to reproductive age, and has been accompanied by major changes in fertility rates, increasing urbanisation and accelerating migration. These trends will have far-reaching implications for generations to come.
Prof Stiegler: The acceleration of population growth since the industrial revolution is indeed due to progresses in mortality and access to medication (especially antibiotics), and at the same time a high level of fertility.
These evolutions are not similar in all regions of the world: the demographic transition has reached its last stage in Europe or in North America, for instance, with an increase in life expectancy and a rapid decrease in fertility leading to population aging and stability, or a decrease in population's size.
In sub-saharan Africa, on the other hand, the demographic transition is not complete: life expectancy tends to increase but fertility is still higher than the replacement level (the average number of children born per woman), therefore the population's size grows, and sometimes very rapidly like in Nigeria or the DRC, for instance.
This growth means that developing countries will have to deal with great numbers of young people who need to be educated and employed. If indeed education, health and employment are provided to these huge young populations, then countries will harness the benefit of such a demographic structure, called the demographic dividend.
This refers to the growth in an economy that is the result of a change in the age structure of a country's population.
If not, such an age distribution, with uneducated and unemployed youth, could turn into a real demographic bomb.
WHO: The recent past has seen enormous changes in fertility rates and life expectancy. In the early 1970s, women had on average 4.5 children each; by 2015, total fertility for the world had fallen to below 2.5 children per woman. Meanwhile, average global life spans have risen, from 64.6 years in the early 1990s to 72.6 years in 2019.
Prof Stiegler: Such numbers show that the population is aging, and that the population will continue to grow, but slowly. However such numbers hide huge geographical disparities. With countries like Italy or South-Korea where the number of children per woman has fallen below the replacement level (2.1 children per female) while in some countries like Mali or Niger, for instance, women have more than 4 children on average.
Therefore, very different population programmes and policies will have to be developed depending on the structure and distribution of the population: policies for aging populations in developed countries and policies for young populations in developing countries.
WHO: The world is seeing high levels of urbanisation and accelerating migration. 2007 was the first year in which more people lived in urban areas than in rural areas, and by 2050 about 66 per cent of the world’s population will be living in cities.
Prof Stiegler: It is true that populations are moving in big economic centers, in megalopolis - as with Lagos for instance (12 millions inhabitants) - posing several issues. The first one, of course, is a problem of space, density and lodging, but it also comes with economic issues and saturated labour markets, to the detriment of smaller cities and agriculture. Finally, in the past few decades it has posed urgent environmental and ecological problems with waste management, pollution and emissions of carbon gas.
The geographical distribution of populations is a real issue that touches the great majority of countries. More and more countries realised the danger of the concentration of populations in urban areas. They are now developing population and economic policies to better distribute populations. Developing countries must absolutely develop population policies and programmes that take into account more harmonious economic and spatial development.
WHO: These megatrends have far-reaching implications. They affect economic development, employment, income distribution, poverty and social protections. They also affect efforts to ensure universal access to health care, education, housing, sanitation, water, food and energy. To more sustainably address the needs of individuals, policymakers must understand how many people are living on the planet, where they are, how old they are, and how many people will come after them.
Prof Stiegler: One big challenge for demographers is to know population size, structure and distribution. It is only by knowing these three essential population components that one can develop adequate population and development policies and programmes. Therefore, countries must improve the way they count their populations, especially in developing countries where data are scarce, by putting in place correct civil registration systems and running much needed population censuses on a regular basis, as well as demographic and socioeconomic surveys.
Accurate population data at a small geographical level are the first step to good population policies and development programmes that include all people, without forgetting those who are too often marginalised, such as females, seniors, the disabled and youth.
Prof Nancy Stiegler is the head of the Statistics and Population Studies Department at the University of the Western Cape (UWC).