Overpopulation (an Economic Issue)
For most of our early history, there were no more than 50 million humans on Earth. Then, we learned how to increase our food supply by growing our own food and by tapping into the earth's mineral resources. With a more stable food supply, we could devote our time to creating better tools, and our population grew. Over time we were able to gain more and more control over our environment and extract even more of its resources, which allowed our population to explode dramatically. Even so, there were still less than a billion people in the world until sometime after 1800.
Even with the industrial revolution and with our expansion into the new world, our population only reached 1.2 billion by 1850 and 1.6 billion by 1900. Then, with our growing use of oil and other nonrenewable natural resources and our advancements in technology, our population growth continued to accelerate. By 1950, the world's human population had grown to about 2.5 billion. By 2000, it had passed 6 billion, and by 2023 it had passed 8 billion.
Today, in the early 2020’s, an additional 83 million of us are being added each year. By 2050, the United Nations estimates we could reach 9.8 billion. Many of us are living longer and richer lives than our ancestors could have ever imagined, but more and more of us are sinking into poverty, and dying of disease and starvation.
It would be great if we could solve our poverty problem so that everyone could live a good life. Our dilemma is that our planet’s resources are finite. In fact, we have already stretched many of these resources to their limits and may soon deplete many of our nonrenewable resources. There simply are not enough resources to provide all our world’s current population with what they would need to get out of poverty. Therefore, it would seem unlikely that we could come up with the resources needed to support an even larger population.
The latest estimates now predict that the world’s human population will be about 11.2 billion by 2100. With each additional person, comes a demand for additional resources. Even if the percentages of our poor, middleclass and wealthy stayed at the same levels as they are today, we would still need 30 to 50 percent more homes, cars, food, fuel, and other goods. This also means a 30 to 50 percent increase in the demand for our planet’s limited resources. Given this, we are faced with the possibility of an even larger share of our population descending into poverty.
In nature, there are many checks and balances that help to control the size of plant and animal populations. When things are in balance, most plants and animals can thrive and remain healthy. When things get out of balance, many plants and animals will suffer or even be driven to extinction.
The size of various plant and animal populations has always been limited by the availability of the resources that they need. If a resource becomes less available or a population grows too big, members of that population would not have the resources they needed to survive.
For animals, food is one of their most important resources. Most animals are herbivores, which means they need some specific forms of plants for food. Other animals are carnivores, which means they eat other animals. This dependence on other life creates a food chain where plants are eaten by certain animals and those animals are eaten by other animals.
We can demonstrate one form of nature’s checks and balances using a simple food chain made up of just plants, rabbits and foxes. In this example, each is needed to keep all their populations in balance through a process of dynamic feedback. If the rabbit population increases, they might eat up all the plants, but more rabbits would allow the fox population to grow. More foxes would eat more rabbits, which would prevent the rabbits from eating up all the plants.
The overall limit on all these populations of plants and animals is the availability of resources like land, nutrients, water and sunshine that are needed to support plant life. For instance, if there is a drought, there would be less water to support plant growth. If rabbits could not get enough plant food to eat, many of them would starve. With fewer rabbits, many foxes would also starve. On the flip side, more plant life would support more rabbits and more rabbits would support more foxes.
In general, the population of each living thing checks the growth in population of other living things and helps to bring all their populations into balance. Of course, if there are no plants then there are no rabbits and without rabbits there would not be any foxes. There can also be a problem if there are no foxes to control the rabbit population. In that case the rabbits would continue to multiply until they had eaten all the plants. If all the rabbits do not die off, then a new unhealthy balance will be reached. The rabbits will keep the plant life from rebounding while they survive at near starvation levels.
When the population of some animals gets too large, it is more vulnerable to disease and to natural disasters. As an animal’s population increases, its members get crowded closer together, which puts a strain on their food supply and many of them do not get enough to eat.
With an animal’s population crowded together and weakened, its members become more susceptible to catching and spreading disease, which thins out the population. In addition, fires and floods can destroy much of an animal’s food supply and kill off some members of its population. If the surviving population remains too large, the reduced food supply will result in more of its members being weakened and susceptible to disease or dying of starvation.
For a long time, human intelligence has basically allowed us to override nature’s checks and balances, and to reduce our susceptibility to disease and natural disasters. We have placed ourselves at the top of all the world’s food chains. We have also learned to protect ourselves against many diseases and natural disasters. This has allowed our human population to grow far larger than any animal of similar size would naturally be able to sustain.
Even at the top of the food chain, we generally only eat from a limited variety of the world’s plants and animals. Therefore, to maximize our food supply, we have taken over large amounts of land so that we could dedicate that land to producing just our food. We have also made great strides in maximizing the yields for our food and in keeping most other plants and animals off this land and away from our food.
Although our actions have allowed our population to increase dramatically, they have severely restricted the populations of most other plants and animals. In addition, our actions have caused and are continuing to cause the extinction of many plant and animal species.
Today, we may have reached the limits of what we can do to support a larger population. Earlier gains against disease are being erased by drug resistant bugs whose spread is being aided by our overcrowding and global travel. Pollution, poor diets, lack of exercise, and our own technology are killing more and more of us. Overcrowding and the shifting of our populations into fringe areas are making more of us vulnerable to natural disasters. We are also stretching our supply of renewable resources and depleting our nonrenewable mineral deposits and energy reserves.
There is now very little land left to increase our food production, since most of the most productive land is already being used for farming and ranching, covered over by roads, parking lots and buildings, or used as yards and recreational parks. Therefore, we are using more marginal land that is not well suited for farming. We are also over farming our land, which is depleting its nutrients and reducing its future yields. In addition, we are irrigating more of our crops with water from deep aquifers that are not being replenished and will therefore eventually run dry.
We are also depleting and losing some of the sources of food that we still get from nature as opposed to what we grow or raise ourselves. This is especially true for seafood. As we have depleted the supply of one food, we have often simply turned to another food supply. If we had competition for our new food supply, we reduced or eliminated it. Then, as we depleted each new food supply, we turned to yet another food supply.
However, each new food supply has been less desirable than the last. Eventually, if things continue as they have, we will have eliminated all other competition and become more dependent on less desirable foods. Then, our only competition may be from other humans.
The bottom line is that the actions we have taken to allow our population to increase have greatly reduced the diversity and amount of biomass in the world, of which we already consume more than 40%. If our population continues increasing, the day may come when we have destroyed almost every other living thing except for those we need for our use and those that can live off our waste.
On the other hand, before we can destroy our environment completely, our demand for some critical resource will most likely exceed or deplete its supply. This could lead to massive starvation, disease, war and the horrifyingly rapid decline of our human race. One way or another, our population will come down. We either must do something about it ourselves in a controlled and orderly fashion, or we can let nature’s checks and balances dramatically reassert their influence and reduce our population for us.
During much of early human history, we had a simple, but effective, solution to any overpopulation. Our excess population simply moved to a new location, which resulted in early humans spreading out over most of the planet. Later, when most places were already settled, we often had to fight for land, which meant those we replaced would die or we died trying to displace them. On the other hand, for the early inhabitants of Easter Island (See Resources) and other isolated populations, there was nowhere to go, and any excess population meant starvation for many.
In the past 500 years or so, many of us had the option of coming to the new world where it was less crowded. Unfortunately, we have now run out of new places to move to. That is until that day in the distant future when we have the means for large numbers of us to colonize other planets. In the meantime, we must find new ways to limit our population or suffer the consequences.
First, we must decide how many humans can comfortably live on the Earth. This would need to be in a way that did not deplete nor even strain our natural resources, and that would allow us to leave adequate natural habitat so that we can share our world with a complete diversity of plants and animals. When coming up with this number, we also want to consider keeping the number low enough so that we all can have the chance to enjoy the world’s natural wonders without overcrowding.
There will obviously be some disagreement as to the number of humans that the world would reasonably be able to support. The thing to keep in mind is that it would be better to put this number a little too low than too high, because it is better to have some extra resources available in case of an emergency, than to risk having shortages. Of course, as time went by, we would gain a greater understanding about what resources we really needed, and we would be able to improve the accuracy of this number.
Then, we would need to come up with a way to reduce our current overpopulation. If we were talking about an animal population such as one for deer, then we would talk about culling the herd as being an effective and humane choice. Obviously, this would not work with our human population. Once born, everyone should be given an appropriate opportunity to live as good a life as possible within the limitations of our available resources.
We must also understand that everyone does not need to be born now. It would be better for a person to be born and to have a good life sometime in the future than to be born now and to live in poverty. The bottom line is that we want our human race to have a long and glorious future where everyone that is born will have the best chance for a good life.
Therefore, we need to reduce the human birth rate below what would be needed to sustain our current population. Once we have reached a sustainable population, the birth rate could come back up to the point where our population would be sustained. The best way to do this would be to aim for a birth rate that would result in the same number of births as there would be once the population reached a sustainable number and the birth rate at that time would create a stable population size.
Although we often talk about births in terms of birth rate, which is usually given in number of births per year per 1000 people, it would be easier to discuss births in terms of the fertility rate. The fertility rate is the average number of children that would be born per woman if all women lived to the end of their childbearing years. Since women make up approximately half the population, a fertility rate of about 2.0 would be needed to sustain the population. This fertility rate could be called the replacement rate.
In 2020, the estimated world fertility rate was 2.56, which is why our world population is still increasing. Of course, fertility rates vary greatly from country to country. For instance, the fertility rate was 7.75 in Niger and 0.91 in Macau. In the United States, we were just about at the replacement rate with a fertility rate of 2.04. In many other industrialized nations, the fertility rate was below the replacement rate. For instance, the fertility rate was 1.66 in the United Kingdom, 1.58 in Canada, 1.41 in Germany, 1.31 in Italy and Spain, and just 1.21 in Japan.
There are many things that contribute to the current differences in fertility rates. First off, many of our ancestors needed to have lots of children to sustain their population, because there was a high child mortality rate, which meant fewer women reaching childbearing age. In countries with a high fertility rate, women still have a lot of children, but the child mortality rate is now lower. In industrialized countries, women are having fewer children due to women delaying pregnancy to have a career, due to the higher cost to raise a child, and due to fertility problems resulting from things like pollution and the many harmful chemicals that are now in our food and water.
In addition to the fertility rate, the immigration rate is the other major contributing factor to population size. For instance, even in a country with a high fertility rate can still maintain a relatively constant population If enough individuals immigrate to other countries. On the other hand, a country with a very low fertility rate can still have a growing population by allowing a lot of immigration from other countries.
Given the vast differences in fertility rates and the differences in how overpopulated different places may be, different plans may be needed for different places. One approach might simply be for each country to adjust its fertility and immigration rates until the population level stabilizes at an appropriate level. However, if too many countries relied on a lot of their population immigrating to other countries instead of lowering their fertility rate, then this would not work very well.
The best idea might be for every country to aim towards having a replacement rate for both fertility and immigration. Therefore, the fertility rate should be about 2.0 and the net immigration to and from the country should be about zero. Of course, countries might decide to partner up so that their combined fertility and immigration rates would be closer to being replacement rates.
A very important part of this plan would be that it must be implemented worldwide. It would not be fair for some countries to do the hard work of reducing the world’s overpopulation while other countries churn out lots of new individuals. If a country did not limit their population growth, then the other countries of the world would need to block any immigration from that country. Without the relief of individuals leaving, the non-compliant country would be forced to deal directly with their own overpopulation problem.
In countries with a high fertility rate, they would need to create incentives through changes in laws and procedures that would limit their birth rate. The People’s Republic of China had recognized their overpopulation problem and had implemented a plan to deal with it. They had a law that limited most couples to just one child, which should have brought their fertility rate down close to 1.0. Although the law had brought their fertility rate down to 1.79, it had not worked as well as they had intended. Even with the problems they had in enforcing their law, it was helping to reduce their overpopulation problem. However, they did put their population out of balance with respect to having too many older people and not enough younger people, and too many male children as opposed to female children. Even so, their law may be a good starting point for our discussion.
If a country was overpopulated and had a high fertility rate, I would propose that they start by giving each person the right to parent two offspring. Basically, this would allow each couple to have two children. We may need to work out a few issues with children from previous marriages, but with everyone having the right to two offspring you just need to find someone with enough remaining rights. In addition, if a child does not live long enough to reproduce, then the couple should be given the right to have another child.
At first, there would be neither exceptions nor the buying or selling of one’s right to have children. With some individuals and couples not having any children or only having one child, the population would, over time, steadily drop to a more sustainable level. Later, after reaching the country’s population goals, couples could obtain the right to have more children, so that the country could maintain a steady population. Eventually, the natural fertility rate might approach 2.0 so that the limits could be removed.
If a country was overpopulated, but had a moderate or low fertility rate, then the country would first need to address their immigration rate. The country would need to place very strict limits on the number of individuals who immigrated to their country to bring down their net immigration to and from their country to about zero. I believe this is the situation that we currently have in the Unites States and in many European countries.
If a country was not overpopulated and had a low fertility rate, then they may need to raise their fertility rate. This would require addressing various pollution, lifestyle and cost issues. Care would be needed so that fixing these problems did not cause the fertility rate to go up too much.
Migration and Immigration -
Managing Migration and Immigration to prevent overcrowding.
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