At the start of 2021, iD4D has chosen to analyze the big demographic trends at work in the world. This first episode of our series “Tomorrow, 9 billion people” gives an overview of these major developments.

Audience at a concert in Taipei, capital of Taiwan (Photo de PATRICK LIN / AFP).
Audience at a concert in Taipei, capital of Taiwan (Photo de PATRICK LIN / AFP).

In less than half a century (2000-2050), the world population will have undergone two major trends: more young people in the developing world and more old people in the “rich” countries. Demographics are changing both within the borders of countries and beyond. This trend is affecting geopolitical, economic, societal, and environmental balances around the world and, more broadly, development models.


Population dynamics: the new world (young-poor) vs. the old world (old-rich)

Africa is home to 75% of all people under age 35 and to only 3% of those over 65 (2019 figures). Integrating young people into economic and social life thus remains and will remain the major challenge for public policies in Africa. New development models will focus on youth, with all its assets (dynamism, mobility, innovation) and challenges. This means that investment in access to quality public services (health, education, environment) throughout Africa, as well as in gender equality, will be a vital issue.

We will increasingly associate the “developed countries vs. poor countries” image with that of “old countries vs. young countries,” but with the awareness that there are a certain number of intermediate countries.

There are now nearly 2 billion people age 10 to 24 in the world. This is the largest number of young people ever in history, and that number is increasing in developing countries.



China will see a decrease in its population in 2050 and the United States a slight increase. As for Europe, it will experience a decrease and will have the largest share of people age 65 and over (more than 23%). Meanwhile sub-Saharan African countries in particular will continue to experience sustained population growth.


Massive growth in new forms of urban living

In 2050, urban populations will have grown by 59% and will account for nearly 70% of the world’s population. By that year, they will reach nearly 6.7 billion people, compared to 4.2 billion today.

By 2030, the world will have 43 megacities compared to 31 today. Their populations will surpass 10 million each. Most of these megacities will be located in developing countries, with 22 in Asia (mostly in India and China).

Africa will be home to 6 megacities of more than 10 million people by 2050. Its population densification will come mainly from rural areas. In fact, the rural urbanization there will be so massive that the number of African city dwellers will exceed the number of Chinese city dwellers by 2041 and make up a quarter of the world’s urban population in 2050.

Cities will continue to be centers of creativity and economic growth, but they will face huge challenges in infrastructure, sanitation, transport, and environmental risks.


Population growth and sustainable development: the “Chinese model” and the African equation

The economic model for a planet of 9 billion people will have to adopt a new approach to current production and consumption patterns. There is a definite link between population size and use of resources and their degradation and disappearance (through overexploitation of land and forests, fishery resources, and water). Nonetheless, countries with high population growth and low living standards have a much smaller ecological footprint than do countries with low or stagnating population growth and whose development model exerts a big environmental impact.

Most African countries will have to perform a balancing act between their demographic growth and their sustainable development needs and constraints. This comes against a backdrop of heightened inequality, which is a growing source of conflicts (over land and water) and exploitation of all kinds.

Is China an example to follow? Over the past 15 years, China has demonstrated that a country with high population-growth potential can engage in a process of swift catching up and assimilation, firstly in terms of industrial manufacturing developments and next in terms of information technologies produced elsewhere. This process allowed China not only to generate capacity for individual and collective savings, but also to structure its labor market and help develop an increasingly skilled workforce. But environmental and biodiversity costs will increasingly become factors affecting future policy choices.

The question is whether other countries currently experiencing similar demographic trends, especially those in Africa, can establish stable jobs within their borders. And to do so, they must meet the political, educational, and organizational conditions—as well as have sufficient attractiveness—to draw capital and to develop manufacturing and/or technological capacities domestically. And, of course, they will have to follow a trajectory of ecological sustainability.


Migratory flows that are varied but still largely regional and continental in nature

As the world crystallizes into an old and rich bloc (tempted to close in on itself) and a young and poor bloc (tending to expand), will it lead to permanent and growing tension? Or, will a new type of international relations ensue?

Between 1990 and 2019, the percentage of international migrants increased from 2.7 to 3.5% of the world’s population. Nonetheless, cumulative global migration characterized by South-South, North-South, and North-North movement remains higher than South-North migration. This also holds true for Africa, where migration is likewise predominantly internal, within the continent.

The key determinants of African migration continue to be historical and linguistic ties. According to a recent study, the main migration corridors between Africa and France remain Algeria and Morocco. African migrants are younger than those from other regions. Further, the share of women among African migrants who settle in OECD countries is increasing. They represented 48.3% of African migrants in 2015‑2016 compared to 46.7% in 2000‑2001. Gender parity is therefore not far from being achieved.

The level of education of African migrants is also increasing. It is estimated that the migratory trend among increasingly younger and more educated people will continue to grow. However, the fact remains that perceptions of “mass” migration by some people in European countries have led to a trend of rejection, and this trend has been hijacked politically and widely relayed by numerous media.


Fertility rate and aging: demographics as the focus of society’s choices for 2050

Population growth is one of the determinants of migration flows. However, fertility-rate control, provided that it is recognized, accepted, and implemented by the countries concerned, is one lever of public policy that should not be overestimated. However, the major trends in African demographics will be present for the next 30 to 50 years, as the births ensuing from population growth have already taken place. While family-planning efforts are useful in helping to lower fertility rates, results will be felt only in the long term.

Meanwhile, by 2050, global aging will have major implications: it is estimated that 82 countries will see at least 20% of their population age 65 and over. These changes in countries’ age structure will have significant consequences on their economic and social trajectories, resource allocations, and public policies.

An increasing number of countries are undergoing and will continue to undergo a steady increase in the number of older persons, both in absolute terms and as a percentage of the total population. Those countries, which have technology and capital available, will not be those that have dynamic working populations. They will have to adopt public policies to make up for the “missing” work force. The types of policy will depend on the degree and pace of aging there as well as on their societal customs. The policies could include savings incentives to promote productive investment, greater participation by women in the labor market, pension system reforms, strengthening of social protection systems, and integration of incoming migration flows.

It will be necessary to think about demographic globalization in relation to economic and financial globalization. Because of this trend, these countries will face growing challenges to find a balance between the retirement, health, and other benefits that older people typically receive, and the investments that will be needed for younger generations. Trade-offs will include incentives for older people to stay longer in the labor market, the use of inward migration flows, and a combination of both of these.



Our series “Tomorrow, 9 billion people”

Episode 1: Worldwide demographic change: new horizons for development

Episode 2: Migration viewed from the North: navigating among reality, ideology, and political choices

Episode 3: Environmental sustainability: the “demographic bomb” myth

Episode 4: Comparative views on population growth and urbanization in the South

Episode 5: The need for a new global sustainable development pact adjusted to planetary demographic dynamics


The opinions expressed on this blog are those of the authors and do not necessarily reflect the official position of their institutions or of AFD.

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