Original version published 1996 and revised 2001 can be found at maxmore.com. Revised version published on KurzweilAI.net April 9, 2001.

The prospect of living longer appeals to many people. Extending lifespan more drastically beyond the current genetic limit of 120 years appeals especially to persons of independent mind. These are people used to going their own way, questioning traditional beliefs, and asserting their values independently of those around them. Yet even we independent thinkers are social beings. Many of our goals require the support of others, and achieving extended life is one of these. We can exercise, diet, and develop healthy psychologies mostly alone or with a few fellows, but scientific breakthroughs in longevity will not happen without broad support and funding. New treatments may be delayed or prohibited if the cultural and legal mindset moves against “interfering” with the human lifespan.

Recognizing these social factors, many of us frequently find ourselves persuading others that extending life is a desirable goal. In making the case for active support of life extension or cryonics, several arguments come up over and over again. We are told that our limited lifespan is natural, or that it is God’s will, or that extreme longevity would drain life of meaning. More common than these objections, we hear fears about overpopulation. Since the 1960s, with the advent of bestsellers like Paul Ehrlich’s The Population Bomb, writers have been getting rich by proclaiming humankind’s impending doom due to overpopulation. In this essay, I hope to provide a compact response to this concern. For more detail, I urge the reader to consult the references at the end.

1. Let us assume for a moment that population growth is or will become a serious problem. Would this give us a strong reason for turning against the extension of human lifespan? No. Opposing extended life because it might add to existing problems would be an unethical response. Suppose you are a doctor given a child to treat who is suffering from pneumonia. Would you refuse to cure the child because then she would be well enough to run around, fall down, and skin her knees? Our first responsibility is to live long and vitally and to help others do the same. Once we are at work on this primary goal, we can focus more energy on solving other challenges. Life extension and optimal living for the individual certainly benefits from a healthy physical and social environment. The life extensionist may want to be part of the solution to any population issues, but dying is not a responsible or healthy way to solve anything. Besides, if we take seriously the idea of limiting lifespan to control population, why not be more active about it? Why not encourage suicide? Why not execute anyone reaching the age of 75?

2. Limiting population growth by opposing life extension not only fails the ethical test, it also fails the pragmatic test. Keeping the death rate up simply is not an effective way of slowing population growth. Population growth depends far more on how many children families have than on how long people live. In mathematical terms, longer life has no effect on the exponential growth rate. It only affects the constant of the equation. This means that it matters little how long we live after we have reproduced. Compare two societies: In country A, people live on average only to 40 years of age, each family producing 5 children. In country B, the lifespan is 90 years but couples have 4 children. Despite the much longer livespan in country B, their population growth rate will be much lower than that of country A. It makes little difference over the long term how many years people live after they have had children. The population growth rate is determined by how many children we have, not how long we live.

Even the apparent short term upward effect on population due to a lower death rate may be cancelled by a delay in child-bearing. Many women in developed countries (those who will be first to have extended life) choose to bear children by their early ’30s because their chances go down as they age. Extending the fertile period of women’s lives would allow them to put off having children until later, while they concentrate on their careers. Not only couples have children later, they will be better able to care for them, financially and psychologically.

Even if there is a population problem, extending the human life span will worsen the problem no more than will improving automobile safety or worker safety, or reducing violent crime. Who would want to keep these deadly threats high in order to combat population growth? If we want to slow population growth, we should focus on reducing births, not on raising or maintaining deaths. If we want to reduce births, we might voluntarily fund programs to provide contraceptives and family planning to couples in poorer countries. This will aid the natural developmental process of choosing to have fewer children. Couples will be able to have children by choice, not by accident. Women would also be encouraged to join the modern world by gaining the ability to pursue vocations other than child-raising.

3. We have seen that we have no reason to hesitate in prolonging life even if overpopulation really is a concern. But how much should we worry about the growing population? Is population growth accelerating out of control? Is expanding population causing major and unavoidable problems? The fad for popular books foretelling doom started in the 1960s, at the tail-end of the most rapid increase in population in human history. Growth has been slowing down, and we have sound reasons to expect this trend to continue. In the Western world, population has stabilized. In some countries, such as Germany, the size of the population is actually falling, as more people die than are born. The population of the USA would be static were it not for an influx of new mind and muscle through immigration. The poorer countries, well below us in the development cycle, have also been experiencing a drastic reduction of population growth, despite extra decades of life bestowed by medical intervention and nutrition.

The peak average annual population growth rate was reached in 1970 at 2.07%. The rate for 1997 is expected to be 1.36%. Developmental trends suggest that this growth rate will drop below 1% in 2016, and fall to around 0.46% by 2049. Every year at present, the world population grows by around 80 million people. By 2050, we will be adding perhaps 40 million per year, a number that we can expect to continue dropping. This slowing of population growth results from a falling birth rate. The birth rate in Asia and the Pacific, between 1950 and 1980 fell 28.8%, and in the Americas by 24.7%. Africa, further behind on the development curve, reduced its birth rate by 2.2% in the same period, all of it being in the second half of the period. Overall, for the less developed countries, birth rates fell 24.9% from 1950 to 1980. Here are the figures in table form:

Crude Birth Rates 1950-1980 and Crude Birth Rate Declines 1950-65, 1965-80, and 1950-80:

	1950	1965	1980	1950-65	1965-80	1950-80
Africa	46.9	47.1	46.1	-0.2	2.4	2.2
Americas	42.2	40.2	32.4	5.8	19.6	24.7
Asia & Pacific	40.9	39.4	30.0	4.1	26.2	28.8
Total	41.8	40.5	32.6	3.7	22.3	24.9

Source: Mark Perlman, “The Role of Population Projections for the Year 2000” in The Resourceful Earth, eds. Julian L. Simon & Herman Kahn.

Why, though, should we expect people in less developed countries, even given contraceptives, to choose to have smaller families? This expectation is not merely speculation based on recent trends. Sound economic reasoning explains the continuing trend, and makes sense of why Africa is only just beginning to make the transition to fewer births.

Decelerating population growth appears to be an inevitable result of growing wealth. Early on in a country’s developmental curve, children can be regarded “producer goods” (as economists would say). Parents put their children to work on the farm to generate food and revenue. Very little effort is put into caring for the child: no expensive health plans, special classes, trips to Disneyland, X-Men action figures, or mounting phone bills! As we become wealthier, children become “consumer goods”. That is, we look on them more and more as little people to be enjoyed and pampered and educated, not beasts of burden to help keep the family alive. We spend thousands of dollars on children to keep them healthy, entertain them, and educate them. We come to prefer fewer children to a vast mob of little ones. This preference seems to be reinforced changing tastes resulting from improved education. The revenue vs. expense equation for extra children further shifts toward having fewer offspring as populations become urbanized. Children cost more to raise in cities and can produce less income than in the country.

Fertility declines for another reason: As poorer countries become wealthier, child mortality falls as a result of improved nutrition, sanitation, and health care. (Reduced child mortality in modern times can come about even without a rise in income.) People in poorer countries are not stupid: they adjust their childbearing plans to reflect changing conditions. When child death rates are high, research has shown that families have more children to ensure achieving a given family size. They have more children to make up for deaths, and often have additional children in anticipation of later deaths. Families reduce fertility as they realize that fewer births are needed to reach a desired family size. Given the incentives to have fewer children as wealth grows and urbanization proceeds, reduced mortality leads to families choosing to reduce family size.

Economic policy helps shape childbearing incentives. Many of the same people who have decried population growth have supported policies guaranteed to boost childbirths. More than that, they boost childbearing among those least able to raise and educate children well. If we want to encourage people to have more children, we will make it cheaper for them to do so. If we want to discourage fertility, or at least refrain from pushing it up, we will stop subsidizing it. Subsidies include free education (free to the parents, not to the tax-payers), free child health care, and additional welfare payments to women for each child they bear. If parents must personally bear the costs of having children, rather than everyone else paying, people will tend to have just the number of children for whom they can assume financial responsibility.

4. We can expect population growth to continue slowing until it reaches a stable size. That may be 12 billion, perhaps 15 billion. Can the Earth support such a number? We can take little comfort in stable numbers if those numbers are unsustainable. A detailed answer to this question demands far more space than I have here. References to excellent writings on the subject can be found in the Further Reading appendix. A few brief points will have to do here. A reading of economic and social history quickly makes one thing plain: Throughout history people have thought they saw overpopulation. Even the great nineteenth century social scientist W. Stanley Jevons in 1865 claimed that England’s industrial expansion would soon cease due to the exhaustion of the country’s coal supply. However, as shortages developed, prices rose. The profit motive stimulated entrepreneurs to find new sources, to develop better technology for finding and extracting coal, and to transport it to where it was needed. The crisis never happened. Today, the USA has proven reserves sufficient to last hundreds or thousands of years. If one resource does begin to run low, rising prices will encourage a switch to alternatives. Certainly, even a vastly bloated population cannot hope to exhaust energy supplies. (Solar energy and power from nuclear fission and soon fusion are practically endless.) So long as we have plentiful energy we can produce substitute resources and even generate more of existing resources, including food. Even if population continues to grow well beyond 15 billion, we can expect human intelligence and technology to comfortably handle the numbers.

5. Neither should we expect pollution to worsen as population grows. Contrary to popular belief, overall pollution in the more developed countries has been decreasing for decades. In the USA, levels of lead have dropped dramatically. Since the 1960s levels of sulfur dioxide, carbon monoxide, ozone, and organic compounds have fallen despite a growing population. Air quality is major urban areas continues to improve, and the Great Lakes are returning toward earlier levels of purity. This is no accident. As we become wealthier, we have more money to spare for a cleaner environment. When you are hungry for food and shelter and other basics, you will not spare much thought for the environment. So long as mechanisms exist for converting desires for cleaner air and water and space for recreation into the things themselves, we can expect it to happen.

Most effective at spurring the positive changes are markets–price signals creating incentives for moves in the right direction. If polluters must pay for what they produce because their activity intrudes on the property rights of others, they will search for ways to make things with less pollution. Pollution problems do exist. Most of them can be traced to a failure to enforce private property rights, so that resources are treated as free goods that need not be well-managed. Fishing in unowned bodies of water is an example of this. The desertification of collectively or government owned land in Africa is another. We can be reasonably confident that the trend toward less pollution with greater population will continue. Complacency is out of place however. We should press for responsible management of resources by privatizing collectively owned resources to create incentives for sound management and renewal.

6. Human intelligence, new technology, and a market economy will allow this planet to support many times the current population of 6 billion–it can support many more humans than we are likely to see, given trends toward lower birth rates. Many countries, including the USA, have a rather low population density. If the USA’s population were as dense as Japan–hardly a crowded place overall–our population would be 3.5 billion rather than 265 million. If the USA had a population density equal to that of Singapore, we’d find almost 35 billion people here, or almost seven times the current world population. New technologies, from simple improvements in irrigation and management to current breakthroughs in genetic engineering should continue to improve world food output. Fewer people are starving despite higher populations. This does not mean feeling satisfied. Millions still go hungry or are vulnerable to disruptions in supply. We need to push to remove trade barriers, abolish price controls on agriculture (which discourage production and investment), and pressure governments engaging in warfare and collectivization to change their ways.

So long as we continue to allow freedom to generate more wealth and better technology, we can expect pollution to continue abating. More efficient recycling, less polluting production processes, and better monitoring and detection of polluters, along with economic incentives making each producer responsible for their output, will allow us to continue improving our environment even as population grows. Far-sighted engineers foresee a day, not far off, when we will be able to completely control matter at the molecular level, a technology known as nanotechnology. If we achieve this level of mastery, we will have the keys to production without pollution. Another product of molecular manufacturing will be the disappearance of most large-scale, clumsy machinery. Less and less land will need to be used for manufacturing equipment, making more room for people to enjoy. Some manufacturing will be moved into space. The result of these and other changes (some of which are already underway) will be the freeing of the Earth from unwanted, but previously necessary, means and by-products of manufacturing.

Since we are considering the long term, here’s a final thought: If the future feels too crowded for us, we can always leave and make a fresh start. Just as malcontents left Old Europe to come to America’s New World, some of us will leave this planet to found new societies in the unlimited depths of space. New launch systems, new materials, molecular-scale manufacturing, and robotic construction will, in the coming century, open up the space frontier in an affordable manner. Adventurous folks, and those desiring experimentation and the freedom to make major changes, will blast out of the Earth’s gravity well. They will create new habitats in space–not cramped little capsules, but grand, freewheeling, custom space habitats with the comforts of home but fewer of the limitations.

The population issue raises numerous factual, economic, and ethical concerns. I cannot hope to deal with them adequately here. I urge the interested reader to check into the sources listed in the References. I have only sketched lines of thinking showing that we would be severely misguided not to push for extended life out of fear of overpopulation. Let us move full speed ahead with extending lifespan. Once we have vanquished aging, I would expect other threats to life, such as war and violent crime, will become even less acceptable. We can look forward to a long-lived society better off than previous generations not only in economic well-being but in security of life and health.

REFERENCES

Paul R. Ehrlich & Anne H. Ehrlich, The Population Explosion (New York: Simon and Schuster, 1990). The apocalyptic view.

Chris Meyer, “What’s the Matter?”. Business 2.0, April 1999.

Jerry Pournelle, A Step Farther Out (London, W.H. Allen, 1980).

Jonathan Rauch, “The New Old Economy: Oil, Computers, and the Reinvention of the Earth.” The Atlantic Monthly, January 2001.

Julian L. Simon, The Ultimate Resource (Princeton, Princeton University Press, 1981).

–Population Matters (New Brunswick, N.J.: Transaction, 1990).

–“Resources, Population, Environment: An Over-Supply of False Bad News”, Science 208, June 27, 1980, pp.1431-1437.

–“Bunkrapt: The Abstractions that lead to scares about resources and population growth,” Extropy #11, Summer/Fall 1993, pp.34-41.

Julian L. Simon & H. Kahn, eds., The Resourceful Earth (Oxford: Basil Blackwell, Inc. 1984).

J. Peter Vajk, Doomsday Has Been Cancelled (Culver City, CA, Peace Press, 1978).