Is the increase in the world population really a “population bomb”? Beyond the number of inhabitants of the planet, it is our mode of development and its limits that first and foremost need to be questioned.

Des bébés jouent au centre de la Pouponnière à Dakar en 2009. (Photo by GEORGES GOBET / AFP)
Des bébés jouent au centre de la Pouponnière à Dakar en 2009. (Photo by GEORGES GOBET / AFP)

Whenever the relations between populations, food sustainability and, more generally, environmental sustainability are addressed, the specter of the population bomb raises its head. This expression was coined in a spectacular fashion in the late 1960s by the biologists Paul and Anne Ehrlich. While the data, projections and underlying alarmist tone of their thinking are scientifically challenged, the questioning still remains, with in the background the idea that global population growth is, per se, the vehicle of all “the threats” to the world.

Yet it would be just as possible to feed the world population today as to feed 9 billion inhabitants in 2050. While some 700 million people worldwide (with an additional 80 to 130 million in 2020 related to the impact of Covid) were undernourished in 2019 (with a projected 820 million in 2030), it is not due to overpopulation. It is much more issues related to the mode of development and its consequences that need to be taken into account – massive waste, over-consumption, growing global inequalities, degradation of resources, climate change. Not to mention the unfair trade policies and policies for the (de)regulation of the agri-food industry, for example.


Global population growth should not be underestimated



As shown in the table above, population growth will continue in the world due to three main factors: the almost universal decline in child mortality and the subsequent increase in life expectancy, the demographic inertia (demographic momentum) that occurs when young people account for a high proportion of the population, even in countries that have achieved fertility rates of around 2 and, finally, the persistently high fertility rates in Sub-Saharan Africa.

While certain demographers forecast that this population growth will end between 2064 and 2100, it remains a key variable of the equation to define a development model to ensure food and environmental sustainability, taking into account the depletion of resources, various sources of pollution and biodiversity loss. Several levels need to be taken into account: population size, its distribution and, finally, its composition.



Population growth and urbanization: new pressure on resources

While, in theory, population size has obvious consequences, for example, on the match between per capita requirements for agricultural land resources and the availability of arable land, as well as on the ever-increasing demand for drinking water, the geographical distribution and socioeconomic structure of the population require a more detailed analysis.

80% of the world population lives in undeveloped or underdeveloped countries and the projections for international migration flows only marginally reduce this percentage. Indeed, most migrant men and women who leave rural areas go to urban or peri-urban areas within the borders of countries or to neighboring countries.

This urbanization, which affects the majority of the world population in Asia and Africa, will create other forms of pressure on resources, but also negative externalities in terms of pollution, for example. Consequently, with strong population growth and a concentration of people in given territories, the already limited resources are becoming increasingly scarce. These population displacements (whatever the causes) exacerbate the degradation of already fragile environments. Finally, the increase in urbanized areas generates negative externalities that cannot be prevented or reduced due to the lack or weakness of public policies for transport, sanitation or the development of urban facilities.

While rapid urbanization is a real phenomenon in Sub-Saharan Africa, it should not mask the fact that the continent’s rural population will increase by 980 million people (2050), i.e. a third of the world’s rural population. As a result, agriculture will remain predominant in ensuring the nutritional and dietary needs of the continent. They will also be crucial to ensuring a sustainable ecological balance (particularly in terms of the environment and biodiversity).

Finally, the impacts of population dynamics on the environment also depend on the profiles of the various social groups and their differences in terms of the professional and social position, gender, consumption, the use of the available infrastructure and technologies…


Questioning the limits of the dominant development system

The argument often put forward pointing out the link between the number of people in the world and the use of resources and their degradation or loss (in particular the overexploitation of land and forests, fisheries resources and water), however valid it may be, should not overshadow the issue of the dominant economic model for production and consumption which calls into question the mechanisms for environmental sustainability and the sustainability of resources. This is without mentioning social inequalities.

For example, between 2 and 4 billion people around the world do not have adequate access to drinking water. The USA, which only accounts for 5% of the world population, is the third largest consumer of freshwater (1.053 trillion m3 per year), after much more populous countries such as China (1.207 trillion m3) and India (1,182 trillion m3).


The work of the IPCC has contributed to making the issues of climate change central to development and it is now accepted that the current world is reaching the environmental and political limits of an extractive and carbon economic model. This gathered pace starting in the 1950s-1960s in reaction to the devastation of the Second World War. It almost exclusively benefited a very small number of countries and populations (450 million people at most), while generally exploiting the planet’s resources.

This type of system cannot rationally be a development model that benefits 9 billion people. It is a system whose limits are much more ecological, climatic, environmental and social than purely demographic.

The ecological footprint of countries with strong population growth and a low standard of living is incomparably lower than in countries with weak growth or demographic stagnation, which have implemented a development model and production and consumption patterns with a high environmental impact. For example, the ecological footprint (hag per person) stood at 8.33 in North America and 5 in the EU, whereas it stood at 1.39 in Africa and 1.16 in South Assai.


Adapting with a view to climate justice

Can China be a role model? In addition to its millennial history and strong state structures, it has demonstrated that a country with strong demographic potential could undertake a catching-up process and a rapid assimilation, firstly of manufacturing industry developments, then of information technologies produced elsewhere. In four decades, this process, conducted in a context of totalitarian governance, has turned the country into the world’s largest economic power and a leading international financial actor, with the emergence of a middle class and an increasingly structured labor market, with an increasingly skilled workforce.

While these dynamics have reduced poverty, they have not reduced inequalities and have not been based on the rule of law. They are also not on a path of ecological sustainability. Consequently, in view of the Chinese path, it is legitimate to question the trajectories of countries, in particular in Africa, which have the same demographic configuration that existed in China. Even if they created the conditions for a real economic take-off, is it desirable for them and the planet to follow the same model?

African countries are increasingly engaged in a race between their demography and their constraints in terms of the environment, biodiversity and sustainable development. In reality, the equation will remain irresolvable if the issue of climate justice is not addressed very seriously by the international community and in particular by rich countries and countries with weak population growth. By differentiating between developed countries and developing countries, the United Nations Framework Convention on Climate Change (UNFCCC, 1992) recognizes that rich countries which are historically the source of climate change have a specific responsibility. Indeed, the Paris Agreement takes up the notion of climate justice: only rich countries must contribute to the €100 billion fund for adaptation to climate change. We are a long way off this.

The challenge now lies in going beyond simply demographic issues to implement cooperation strategies in order to not only support the efforts of countries of the South, but also collectively promote public policies for adaptation, mitigation and a just transition at global level.



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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