by Alexander Bastidas Fry
Humans have existed for a brief time no matter how you count the eons. Ten thousand years ago there were perhaps some three million humans on earth. Today there are seven billion. It was only in the last century that population growth seemed unbounded, but in reality the average rate of population growth per year in the twentieth century was only a few percent. Quite frankly overpopulation is a myth. It is a dangerous idea that is demonstrably wrong. In developed countries it is actually population decline that presents social and economic challenges. In some underdeveloped nations the population is indeed growing extremely rapidly, however, the situation is ameliorated by humanist efforts such as education (particularly for women), access to contraceptives, and general economic and social empowerment of the population. Overpopulation isn't a problem, but even if it was, the solution would be to give people, particularly women, choices about their own destiny.
A few years ago I was at a conference where a physics Nobel Laureate gave a lucid talk about his subject of expertise, but then at the end he tilted his attention towards windmills. He stated that the increasing world population would doom humanity. He declared support for efforts to restrict the number of children women can bear with social or medical sterilization policies. It is almost excusable that this physicist wasn't aware of global population trends. It is not excusable how anti-humanist this viewpoint is. This misplaced fear of overpopulation is not uncommon. I have heard politicians and dinner party conversation echo the same sentiments. I think the root of the problem starts with ignorance. The results of (a terribly unscientific) survey I conducted found that less than 25% of respondents knew what the current best estimates of the world population would be in 2050. It is under 10 billion by the way. What is more alarming is that 7% of respondents think it is acceptable to control population through any means possible including avoiding addressing scourges such as water shortages, disease, famine, etc. If the root of this problem is ignorance then the rotten fruit is antipathy towards fellow humans.
It is true that the world population is growing rapidly in terms of absolute numbers, but the growth per year has always been less than a few percent. Of course, this growth is compounding. It took eternity until 1804 for the world to reach the first billion. It took 123 years to reach the next billion in 1927. The most recent billion in growth from six to seven billion took only 13. This was one year longer than it took to jump from five to six billion. That means population growth is slowing.
We have to talk about numbers. The numbers tell the story. A story that can be misunderstood. If you naively fit a line to current population growth you may be one of the majority of people who thinks the world population is growing out of control, but one does not simply fit a line to the nuances of human population growth. The United Nations Population Division uses Bayesian hierarchical modeling to explore a range of probabilistic trajectories of future population growth rates (the United Nation's projections on world population do carry uncertainties so I have I have stated here the median likelihood estimates). All the best data shows that global population growth rates are declining. The growth rate from 1950 to 2000 was 1.76%, but from 2000 to 2050 that growth rate is expected to be .77% and already about half the world currently lives in countries with below-replacement fertility (this means that on average each man and woman together will have less than about 2.1 children).
The take away is that nothing is out of control. Increased access to contraceptives, increased access to education and life choices, especially for women, is what humanity needs. Give people knowledge and they will choose right.
The massively successful growth of world's population really began in the 1950s. It was a bad time for Malthusian prediction, but good for humans. Thomas Malthus wrote an essay on overpopulation of the world in 1798 and became the eponymous leader of Malthusians: people who believe the biggest threat to humanity is overpopulation. Historically these people have been more than wrong, they have been pessimistic. One of the common arguments of Malthusian's is that technology removes constraints on population and collectively we will doom ourselves. Historically though, technology comes with social progress and development which changes the entire picture. Beginning in the 1950s the standard of living increased, infant mortality dropped, the happiness index went up, and mortality decreased. The supposed overpopulation problem is a paradox for anyone who wishes happiness upon humanity. Most problems the world faces would be solutions to overpopulation: war, disease, famine, genocide, eugenics, and everything else would be positive. You would have to be a monster to think those are good things. It is morally untenable to hold these scenarios as viable solutions to the overpopulation problem that isn't a problem. And if there was a problem, prosocial solutions are available.
Today the reality is that the world is experiencing falling birth rates and rising life expectancy. Rapidly rising populations are a threat in the poorest countries, while low fertility is a threat to developed nations . The world population is getting much older: by 2050 the number of people over the age of 65 will triple from 531 million to 1.5 billion. In fact, perhaps the real issue of the world population is not those being born, it is those not dying. There is a growing life expectancy gap where the affluent may expect to live to 120 or more while the poor won't see 60 . In most developed countries actual fertility is lower than desired. If you believe that there are too many people on Earth already and have access to contraceptives and have had a child then your position is at best hypocritical. A consistent world view would hold that no one should have more children, but in reality of human nature is that only those who have access to contraceptives can accomplish that. Perhaps we should allow immigration from overpopulated countries to keep the ratio of working age to elderly dependents constant. Unfortunately most immigration policies severely limit the migration of unskilled people.
Each country or region in the world has its own story of population growth. The story tightly follows the development of the region. The overall trend is that Sub-Sahara Africa will see increasing fertility in already populous countries and Europe will shrink . In 2014 a Pew Research center reported that half the world population lived in 6 countries: China, Indonesia, India, Pakistan, Brazil, and the United States. But the population of China, Brazil, Germany, Russia, and even India are all expected to have already peaked or will have peaked by 2050 and will be declining by 2100. A one size fits all demographic vision of the world doesn't work in practice. China has a one child policy. It is euphemistically called the family planning policy. The policy has exceptions, but it is essentially what it sounds like. Next door to China in Japan the one child policy wouldn't fly: Japan has an aging population problem.
The social and economic fabric of a place determines how populations will grow. During periods where the number of children a woman bears drops from several to two or less societies often see increased productivity and investment boosts. But most places on the world have already seen this potential boom happen and have capitalized on it or not. Over 80% of the world has fertility rates below three. Consider that fertility rates below two offspring result in a stable or decrease population size: it takes two. These low fertility rates are the result of personal choice, not government planning or coercion, unless you are in China. Whereas some want less, other want more. In Germany for example, in order to insure demographic stability efforts to reduce the economic and social costs of children may need to be taken by the government.
There are real problems caused by rapid population growth. It is true that the world population is expected to increase from 6.9 billion in 2010 to 9.6 billion by 2050, but we used to grow much faster in relative and absolute numbers. From 1950 to 2010 the world population skyrocketed from 2.5 to 6.9 billion. The most critical time for intervention is when populations are growing quickly. A delay of family planning programs could be very costly in regions of Sub-Sahara Africa where infrastructures are already strained. There are by some estimates 200 million women in the world who want contraceptives. And we must not ignore the fact that education for women is a proven means of reducing fertility. Women who are educated, economically productive, and enabled to make their own decisions about their bodies will have children at a much slower pace: their own pace.
The future has the possibility to be a place where more people live healthier, longer, and more meaningful lives than ever before. However, leaving half the world behind poor and unable to participate is a disaster for everyone due to our shared environment. Developed and rapidly developing nations use natural resources and produce greenhouse gasses at unsustainable levels. It may be that climate change is the biggest threat to humanity collectively. So it may be that a smaller population would decrease the rate of climate change, but then so would educating people about the situation and giving them the choice of better ways of living.
Rather than too many, wouldn't too few be worse? 72,000 years ago a volcano erupted during what is known at the Toba event and genetic evidence suggests as few as 1,000 breeding Homo sapiens were left on Earth. Humans did what humans do, and we survived. It has always been an issue of human nature. Human nature remains paramount today. Let us be explicitly clear about what we are talking about: some people are having sex and some people think they should abstain. The myth that overpopulation is the problem in shrouded by the values and culture of people who make such a judgment. The myth that overpopulation is the problem is not supported by evidence. We should reject anti-humanist solutions. We must celebrate human nature. In particular, the nature for people to choose what is best for themselves, because all the best evidence shows that when given the choices people choose what is best for themselves.