On the one hand, these three numbers: 3 billion people in 1960, 7 billion in 2014, whose half, 3’5 billion, are living in cities. On the other, the obvious: major climate change shook the world during this period.
For many demographers, the comparison is not relevant. But not for everyone. In France, Jacques Véron, a researcher at the National Institute of Demographic Studies, is working to cross population factors, lifestyle and technical progress. He explains that one way to link digitally the population to the environment is to estimate the « carrying capacity ». We are talking, for example, of the capacity of a sheep herd, that is to say, its size limited to and fro which it can no longer live in the area it has chosen without devastate and therefore suffer. Applied to humanity, what is the capacity of the latter on the Earth, to and fro which, life is no longer possible? At what point there will be too many people chasing too few resources? Fear of overflow and its implications for the future of mankind on Earth is not new. What does say Malthus in 1803 of « A man who is born into a world already possessed, if he cannot get subsistence from his parents on whom he has a just demand, and if the society do not want his labour »? He is simply in the way, unwelcome. The formula is famous. It is lapidary: « At nature’s mighty feast there is no vacant cover for him. »
And what happens, says Malthus, if, on the contrary, « these guests get up and make room for him»? Well, in that case, « the happiness of the guests is destroyed by the spectacle of misery and dependence in every part of the hall. »
Jacques Veron seizes this parable of the feast that defends the legitimacy of the populations to consume regardless of the following, to overthrow it. And he contrasts his definition of sustainable development that encourages, instead, to consider the rights of future generations. The overflow –let us remember— the great fear of the mid-twentieth century, « 700 millions de Chinois. Et moi ? Et moi ? Et moi ? »(*). The planet is then in and extensive demographic explosion. Specialists made therefore some calculations and projections that are downright frightening. In 1972 a report by the MIT, on behalf of the Club of Rome, warned about the population growth, a threat to the future of humankind, and as it could ultimately lead to a depletion of resources. It is urgent to stop it.
Fifteen years later, in 1987, the famous Brundtland Report came into the light, in preparation for the Earth Summit. It also called for stabilizing the population at 6,000,000,000. But despite political birth control (especially in China), despite the ongoing demographic transition, that number will be exceeded by 7 billion in 2014, and is expected to reach nearly 10 billion in 2050 and this time … carrying capacity could reach its limit.
One has the feeling that in spite of all these data, the reports are not obvious.
In the 1960s, biologist Paul R. Ehrlich published « The Population Bomb ». It refocuses the environmental question on the issue of population pressure. It leads to conclusions that are not very humanistic, for example, sterilization. Since, in fact, demographers have not been much engaged in the environmental issue as a result of the discrediting of their « anti-humanism». Emmanuel Todd or Hervé Le Bras, only belatedly became interested in these issues, even though environment plays a fundamental role in demography.
As for environmentalists, are they being taken sufficiently into account the concern on population growth? Is there a population problem? If you look at the history of mankind as a trajectory, the last two millennia, people have just about doubled; when in the space of a century, the twentieth, it was multiplied by 6, a sudden acceleration peak in the pace … but then what is the figure of a « normal » population? This calculation depends on scholar lifestyles, available technology, populations’ dispersals, social innovations, wealth sharing, and many other phenomena, well … that give rise to the most fanciful figures on the future. Most likely, it seems, is that around 10 billion. For the moment at least…
But the population is not evenly distributed across the Planet territory. There is a difference here between overcrowding in urban areas and the overall volume of people on Earth.
Urban crowding is a reality: there are local problems of overpopulation, but at the same time this does not imply the existence of a global problem of population growth. The problem is the way of life (we pollute too much, we are consuming too much energy), not the number. This is a « cultural » problem —the well-known « ecological footprint »— that should be fixed. Taking as an example the problem of global warming, and therefore a problem that is not « local », the British environmentalist James Lovelock believes that overpopulation and climate change are two sides of a same coin. However, the most populated regions are not those that emit the most greenhouse gas emissions, but the richest and/or in high-growth regions. The United States has plenty of space for little people —and it is among the largest emitters.
The problem is not how many we are, but how we live. This is a question of social organization, and again, of management and usage of land and resources.
(*) A well know French song by Jacques Dutronc