In a recent column in The New York Times Ross Douthat suggested that the Biden Administration take steps to restore America’s population reproduction rate to the replacement level. This could be accomplished with sustainable economic expansion and job stability, and by lowering the cost of raising children. But more critical in Mr. Douthat’s view is a return to a more traditional culture, one that used to favor child bearing.
Besides the US, sub-replacement birth rates, and for different reasons, are also observed elsewhere, including Europe, Russia and Japan, whereas China has imposed it by design. Although low birth rates are looked at as problematic or even undesirable, they have no easy solutions nor is a boost an unmitigated blessing.
To start with, economic prosperity does not necessarily lead to higher birth rates. In most regions of the world, birth rates have fallen in spite of improved economic conditions. The causes are quite interesting. First, the dramatic fall in infant mortality has made it less necessary for parents to have more children as an insurance against early death. It has been estimated that in historical societies, like those of Greece, Rome, Pre-Columbian America, Medieval Japan and Imperial China, 25% of newborn babies died the first year. Today this rate is down to 2.9%, with the greatest reduction achieved in less developed countries.
Second, the shift of huge numbers of people away from farming to other occupations has lessened the need to have plenty of hands in a family to support the agrarian economy. Third, economic and social gains open up more opportunities for women to educate themselves and join the labor force, the result being later in life and fewer births. With help from modern contraceptive methods, these trends have reduced the average family size, especially in the less developed world. The number of children per woman has declined from 5.8 in 1800 to 2.5 in 2017, and is forecasted to fall to 1.9 by 2100.
It is very doubtful that the powerful effects of the above factors, and especially the one coming from the empowerment of women, can be neutralized by a cultural change that is friendlier to child bearing. But even if such a cultural change were somewhat possible, we have to reckon with the collateral effects of higher birth rates on the earth’s ecosystem.
At present, the earth’s human population stands at 7.9 billion. It is projected to grow to 9.7 billion in 2050 and about 11 billion in 2100. For environmental sustainability the optimal human population is estimated to be between 1.5 and 2 billion people. Considering only the common era, humans numbered around 200 million in 1 CE and 400 million in 1000 CE. We grew to 1,000 million in 1800, 1,650 million in 1900, and 6,100 million in 2000. All in all, it is estimated that about 100 billion humans have been born and died.
The numbers above show that despite the falling rates of births, each century has added and is predicted to add huge numbers of humans to planet earth. Besides this explosion of human population, there are two other factors that impact our natural environment. One is rising technological capacity that enables us to harvest ever more from nature. The other is our growing appetite for overconsumption. To sustain our increasing numbers and consumption needs, we are deforesting lands for mining, timber and farming; we are depleting the seas for seafood; and we are filling the atmosphere with carbon dioxide for manufacturing, transportation, and food production. The warnings from scientists are many and dire. But for reasons associated with religious beliefs, our natural instinct of procreation, and economic interests we seem to turn a deaf ear and avert our eyes from this reckoning.
The most potent explanation for ignoring the ecological consequences of population growth and overconsumption is that countries look at the issue from their own perspective. Let’s concentrate for now on the economic argument. Population growth is economically-speaking important because along with productivity it impacts economic growth. An economy needs increasing numbers of workers and consumers to grow. An economy also needs more young people in order to sustain the cost of its aging population, that is, the cost of health care and retirement income. It is easy, therefore, to understand why each country individually is concerned with its population trend. But what is good for each country separately can be harmful to all if a deteriorating ecosystem eventually puts all humans at risk.
So, we have a three-pronged conundrum. First, as economic conditions improve birth rates fall. Second, adherence to the goal of economic growth requires a replacement birth rate. And third, rising human population and overconsumption depreciate the planet’s ecosystem and threaten our existence or way of life as we know it. What gives?
Some will argue that new technologies will sustain us with less damage to the environment. Others will argue that it is possible to use science and technology to restore any damage we inflict on the ecosystem. What about stemming overconsumption? Or returning to simpler modes of living that reduce the human footprint in nature? All these are tough choices because they require global cooperation and huge cultural change. The human record is barely encouraging in that respect.
What about rearranging the geography of global population by moving poor people to developed economies with declining populations? Assuming for a moment we overcome anti-immigration attitudes, this may help individual countries but not the ecosystem. For example, moving people from Africa to the US would turn users of an average 4,220 kWh of energy to users of 79,897 kWh as US residents. Not so good for the environment.
Birth rates, population growth and ecological sustainability are intricately linked and have no easy answers. In one of his lectures James Watson, discoverer of the DNA structure, was asked whether we will ever manage to extend human life to 150 years. With a grin on his face, Watson replied “before we do that, we need to make sure our legs and brains keep going.” In the same spirit, before we wish higher birth rates and population growth, we need to find ways to save our ecosystem from collapsing, because if that goes so will we.
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