DEBATE
Do we have to put a stop to population growth?
There are very different prognoses about how population growth is going to affect humankind and our planet, from horror scenarios of hunger and misery to utopian visions of co-existence.
Photo: zVg
Photo: zVg
The world population was one billion in 1830, reached two billion in about 1930 and then climbed very rapidly, with a growth rate of over two percent in the 1960s, to four billion in 1974, six billion in 1999 and eight billion in 2022. The UN projections have the population reaching ten billion in 2060. We are adding about 200,000 persons to the planet each day! But the only population growth rate that is sustainable in the long term is 0.0. On a finite planet, this answer seems obvious.
So world population growth has to stop at some point, the question is how and when. Even if fertility declined immediately to two births per woman (exactly replacing her and her partner in the next generation), the population would continue to grow for at least 50 years. This is due to population momentum. The large numbers of young persons alive today means that the population will continue to increase, even if women only have two births each. Take the case of China – even with fertility actually below two births per woman since the 1990s, its population has continued to grow from 1.1 billion in 1990 to 1.4 billion today. It is only projected to plateau and then decline toward the end of the decade.
Again, on a finite planet, population growth must cease at some point. If it does not stop due to the major declines in fertility attributed to the one-child family norm, then it will be stopped as mortality increases with dwindling non-renewable resources, e.g., fossil fuels and minerals. Even renewable resources like underground aquifers, forests and fish are being used beyond their ability to regenerate. This overuse of the planet’s resources obviously cannot continue indefinitely.
There is an even greater challenge: In the peer-reviewed literature, five groups of ecologists have separately estimated the population size that could be supported sustainably on planet Earth. All of their estimates are below four billion! For this population size to be reached without major increases in mortality, a one-child family norm needs to be adopted worldwide, and soon.
Stan Becker is a professor emeritus in population, family and reproductive health at the Johns Hopkins Bloomberg School of Public Health. He is especially interested in issues of reproductive health and population growth.
The world’s population is still growing, but that will continue for only a few more decades according to all forecasts. The peak will come during the second half of the century, perhaps even in the 2050s according to a Lancet study.
It is not possible to calculate a ‘carrying capacity’ for the Earth. The ‘Overshoot Day’ theme is based on far-fetched calculations. We see the Earth as a finite receptacle, but resource economics is a matter of flows and marginal exploitation costs. For example, the Chinese population will not live in fifty years time as Europeans do today. And a highly developed society ensures better protection for its environment.
Then there’s the question of whether population decline mitigates global warming. The biggest polluters are the countries with the lowest fertility rates, meaning the damage caused by rich countries will be increasingly limited. But is this where action should be taken? We have all read that each additional child corresponds to the emission of 58 tonnes of CO2 equivalent per year. Nevertheless, this calculation assumes that a parent would be responsible for half the emissions of his or her child throughout the child’s life, a quarter of the next generation, etc. Are we sure that a smaller population would not be tempted to consume differently? That humans will be more inclined to preserve the planet if they do not aspire to pass it on to their children? Young people remain a creative force. It’s the children being born today who may find the most relevant solutions.
Countries undergoing demographic decline are experiencing or will experience major economic difficulties. Wishing for such a decline is playing with fire.
Finally, it is worth recalling that birth reduction policies only lead to significant effects in the long term. A massive and sudden drop in world fertility would, in the best and most unlikely scenarios, result in less than 30 percent of the reductions needed to avoid a rise of two degrees Celsius in average global temperatures by 2050.
Bruno Tertrais is a geopolitical scientist and the deputy director of the Foundation for Strategic Research in France. He is the author of the book ‘The demographic shock’ (2020).
Photo: zVg
Yes. The world population was one billion in 1830, reached two billion in about 1930 and then climbed very rapidly, with a growth rate of over two percent in the 1960s, to four billion in 1974, six billion in 1999 and eight billion in 2022. The UN projections have the population reaching ten billion in 2060. We are adding about 200,000 persons to the planet each day! But the only population growth rate that is sustainable in the long term is 0.0. On a finite planet, this answer seems obvious.
So world population growth has to stop at some point, the question is how and when. Even if fertility declined immediately to two births per woman (exactly replacing her and her partner in the next generation), the population would continue to grow for at least 50 years. This is due to population momentum. The large numbers of young persons alive today means that the population will continue to increase, even if women only have two births each. Take the case of China – even with fertility actually below two births per woman since the 1990s, its population has continued to grow from 1.1 billion in 1990 to 1.4 billion today. It is only projected to plateau and then decline toward the end of the decade.
Again, on a finite planet, population growth must cease at some point. If it does not stop due to the major declines in fertility attributed to the one-child family norm, then it will be stopped as mortality increases with dwindling non-renewable resources, e.g., fossil fuels and minerals. Even renewable resources like underground aquifers, forests and fish are being used beyond their ability to regenerate. This overuse of the planet’s resources obviously cannot continue indefinitely.
There is an even greater challenge: In the peer-reviewed literature, five groups of ecologists have separately estimated the population size that could be supported sustainably on planet Earth. All of their estimates are below four billion! For this population size to be reached without major increases in mortality, a one-child family norm needs to be adopted worldwide, and soon.
Stan Becker is a professor emeritus in population, family and reproductive health at the Johns Hopkins Bloomberg School of Public Health. He is especially interested in issues of reproductive health and population growth.
Photo: zVg
The world’s population is still growing, but that will continue for only a few more decades according to all forecasts. The peak will come during the second half of the century, perhaps even in the 2050s according to a Lancet study.
It is not possible to calculate a ‘carrying capacity’ for the Earth. The ‘Overshoot Day’ theme is based on far-fetched calculations. We see the Earth as a finite receptacle, but resource economics is a matter of flows and marginal exploitation costs. For example, the Chinese population will not live in fifty years time as Europeans do today. And a highly developed society ensures better protection for its environment.
Then there’s the question of whether population decline mitigates global warming. The biggest polluters are the countries with the lowest fertility rates, meaning the damage caused by rich countries will be increasingly limited. But is this where action should be taken? We have all read that each additional child corresponds to the emission of 58 tonnes of CO2 equivalent per year. Nevertheless, this calculation assumes that a parent would be responsible for half the emissions of his or her child throughout the child’s life, a quarter of the next generation, etc. Are we sure that a smaller population would not be tempted to consume differently? That humans will be more inclined to preserve the planet if they do not aspire to pass it on to their children? Young people remain a creative force. It’s the children being born today who may find the most relevant solutions.
Countries undergoing demographic decline are experiencing or will experience major economic difficulties. Wishing for such a decline is playing with fire.
Finally, it is worth recalling that birth reduction policies only lead to significant effects in the long term. A massive and sudden drop in world fertility would, in the best and most unlikely scenarios, result in less than 30 percent of the reductions needed to avoid a rise of two degrees Celsius in average global temperatures by 2050.
Bruno Tertrais is a geopolitical scientist and the deputy director of the Foundation for Strategic Research in France. He is the author of the book ‘The demographic shock’ (2020).
