The world population exceeds 8 billion inhabitants on Tuesday, according to the official estimate of the United Nations, which sees in it “an important milestone in human development” and a reminder, in the midst of COP27, of “our shared responsibility to take care of our planet”.
For the UN, “this unprecedented growth” – there were 2.5 billion inhabitants in 1950 – is the result of “a progressive increase in the length of life thanks to progress made in terms of health health, nutrition, personal hygiene and medicine”.
But population growth also poses formidable challenges to the poorest countries, where it is most concentrated.
While the Earth had less than a billion inhabitants until the 1800s, it only took twelve years to grow from 7 to 8 billion.
Sign of its demographic slowdown, it will take about fifteen years to reach 9 billion in 2037. The UN projects a “peak” at 10.4 billion in the 2080s and stagnation until the end of the century.
The 8 billion mark is crossed in the midst of the world climate conference, COP27, in Sharm el-Sheikh, which once again underlines the difficulty of the rich countries, those most responsible for global warming, and the poor countries, who are asking for help to deal with it, to agree to more ambitiously reduce greenhouse gas emissions from human activities.
However, recalls the UN, “if population growth amplifies the environmental impact of economic development”, “the countries where the consumption of material resources and the emissions of greenhouse gases per inhabitant are the highest, are generally those where the per capita income is the highest and not those where the population is growing rapidly”.
“Our impact on the planet is determined much more by our behavior than by our numbers,” summarizes for AFP Jennifer Sciubba, researcher in residence at the Wilson Center think tank.
And it is indeed in the countries which already have a high concentration of poverty that population growth poses major challenges.
“The persistence of high levels of fertility, driving rapid population growth, is both a symptom and a cause of slow development progress,” writes the UN.
Thus, India, a country of 1.4 billion inhabitants, which will become the most populous in the world in 2023, surpassing China, should experience an explosion in its urban population in the coming decades with megacities already overpopulated and in lack of essential infrastructure.
In Bombay, about 40% of the population lives in slums, overcrowded areas of poverty, made up of makeshift shacks, most of which lack running water, electricity and sanitation.
The global numbers mask immense demographic diversity. Thus, more than half of population growth by 2050 will come from just 8 countries according to the UN: Democratic Republic of Congo, Egypt, Ethiopia, India, Nigeria, Pakistan, Philippines and Tanzania.
And by the end of the century, the three most populous cities in the world will be African: Lagos in Nigeria, Kinshasa in DR Congo and Dar Es Salaam in Tanzania.