Multiple times in the past few weeks, I have heard fellow students say something gloomy about the issue of overpopulation. I do not think that overpopulation is an issue we should be worrying about.
Before the Industrial Revolution, wealthier families tended to have higher birth rates, but the overall birth rate of a country generally did not have much to do with its wealth. In the case of wealthy families, there was often widespread downward mobility (as poor family lines tended to die out, their social positions taken up by surplus elites). When whole societies became wealthy enough to support overall population growth, this tended to cause resource issues. This led to a decline in the wealth of the society, and population growth tended to stabilize through war, poor sanitation and disease, starvation, infanticide, or some other means. However, industrialization has almost universally brought with it a change to this pattern, with wealthier families and societies having lower birth rates and poor families and societies having higher birth rates. Wages for women are now higher than ever; however, children are no longer as economically productive, leading to a high opportunity cost per birth. It is also easier to avoid births with modern contraceptives, which are not always available in developing nations. Since the world (including most developing nations) is growing wealthier in general, we may expect fertility rates to decline further, and there is currently no clear halt to the trend: According to the U.N., it is plausible that the world population could begin to decline this century.
The fertility rate (number of births per woman) needed to sustain the population is generally assumed to be at least 2.1 births per woman. This year, the [world fertility rate] was about 2.3. It was about 1.7 in the U.S., though our population is still growing. The Census Bureau estimates that the U.S. population will stabilize around 2080 and then decline slightly. The U.S. population is growing (unlike the populations of some other developed countries, like Latvia) largely because of immigration. However, it is not projected to remain the case that some nations’ surplus population will outweigh other nations’ population deficits. The U.S. gains most of our immigrants from Latin America, but Latin America’s birth rates are also declining. The Census Bureau predicts that the percentage of the U.S. that is foreign-born will increase over time, but that the growth rate of the foreign-born population will stabilize toward the end of the century. There are still many countries, especially in sub-Saharan Africa, with overpopulation problems, but if these countries develop more, then their birth rates will also likely decline in time, as they gain access to birth control and the economic motivations of a wealthy society.
Though there are doubtless only enough resources on the Earth for so many people at once, it has begun to be clear that this maximum number of people is so high that we do not really need to worry about it. As the population has grown, we have experienced fewer famines and higher quality of life in general — this is not causal, but negative consequences of population growth at past rates (which are higher than future rates) have come nowhere close to outstripping beneficial technological advancement. Farming has become incredibly efficient. Where famines do occur in the modern world, it is usually because of breakdowns in distribution — almost always political causes like war, state collapse, or deliberate state actions like the Holodomor — rather than genuine food shortages in the world as a whole. We are able to produce energy very cheaply, and when we lack energy, it is not generally because of any lack of natural resources, but because of infrastructure problems (for instance, consider why nuclear reactors are so costly to build in the United States — it’s because of safety regulations, not a shortage in uranium).
The population slowdown brings problems of its own, such as the fact that healthcare costs will increase and worker productivity may decrease with the rising median age, leading to a greater need for social spending without increased revenue. Life’s a pyramid scheme. Who will take care of us when we’re old?
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