The comments in part one reminded me of Joel Cohen’s excellent How Many People Can the Earth Support? (1995)
See bottom* for population projections provided by four different organizations. In the text below, I have not changed assumptions for the most part, though projections on population growth today are lower than 15 years ago.
From chapters 2 – 4
There were perhaps 10,000 humans 80-100,000 years ago at the end of the last ice age (down from a peak of 100,000). They spread throughout the Old World, and then the Americas.
Populations surged with the introduction of local agriculture (from the last ice age to 3000 BCE), and with the global agriculture shifts (from 1650 to 1850), pooling cultivars from different continents. This latter period coincided with the Industrial Revolution. Another surge coincided with the public health improvements (from 1945 to date). Overlapping the latter two periods is a trend of reduced fertility (reducing growth rate, not necessarily the number of people), beginning in France in 1785.
World Population Growth Rates—divide 70 by percent growth rate to get approximate doubling time. [No, climate change is not included in the underlying assumptions.]
Looking at history—what does reduce fertility rates?
Infanticide was used until other methods were found, and is still used in hunter-gatherer societies. Essentially modern people likely used infanticide some 20,000 years ago, as the male to female ratio in skeletons is skewed. Widespread use of other methods to reduce fertility requires parents be willing to consider the thought and behavior acceptable, and find reduced fertility to be advantageous, as city dwellers often do. It also requires access to birth control methods and techniques, and sufficient communication to employ them.
The first unambiguous written evidence of limiting family size by an entire social group appeared at the end of the 17th century in French upper classes. Rather than continuing to bear children until their 40s, the final child was born when women were in their low 30s. The Italian nobility followed. By the last quarter of the 18th century, before the French revolution, practices to limit fertility had spread to peasants throughout much of rural France, with coitus interuptus as the favored method of birth control.
Countries with many migrants from areas limiting birth saw their own rapid declines in fertility. Shared culture facilitated the process. There does not seem to be a connection to existing social or economic conditions—fertility declines occurred during times of low literacy in France, Bulgaria and Hungary, and high literacy in England and Wales, in some countries that were very rural, but in England when only 15% of men worked in agriculture. In France, the decline in fertility was spread over many decades, while in England, dramatic declines in fertility occurred almost everywhere between 1890 and 1900. High income inequality slowed the spread of fertility decline.
The Princeton European Fertility Project failed to find simple explanations to account for fertility decline:
• The decline in mortality rate does not necessarily precede the decline in fertility. In France, they fell together. In Germany, infant mortality fell in parallel with marital fertility beginning around 1870, but in half of provinces fertility fell first, and in the other half, mortality fell first.
• Essentially all explanations (spread of a new mentality, …) lack evidence. Favored explanations include
improvements in the status of women, more secular attitudes and an increasing preference for individual interests over tradition….
Socioeconomic development, improvements in the status of women and secular attitudes may be neither necessary nor sufficient for a fertility transition, whatever other virtues or drawbacks they may have in the eyes of different observers.
(page 62 Joel Cohen How Many People Can the Earth Support?)
Fertility transitions—a decline of 10% in fertility rate (the number of children born per women)—occurred around 1964 in Chile (30% rural), and 1970 in Thailand (85% rural). In 1964, Chile’s infant mortality rate was over 10%, but Taiwan began the transition in 1963 when infant mortality was less than half as large. Mexico’s rapid decline in the 1970s is attributed to “political will”, Brazil’s equivalent decline came without strong government intervention, and India’s government intervention in family planning appeared to have been counterproductive. China’s fertility rate fell from 6.5 in 1968 to 2.2 in 1980, a shift that took 60 years in Great Britain and longer in France. It took 58 years for the US fertility rate to decline from 6.3 to 3.5, Colombia did the same in 15 years, Thailand 8 years, and China 7 years. Simple explanations fail.
Kenya was one of the African countries seeing a decline. What appears to have worked there? The increase in the use of contraception and abortion were part of the cause (abortion was illegal, but Kenya saw a rise in the number admitted to hospitals for complications from abortions). No one “knows” but these reasons are considered plausible:
• Land which once was communal was transferred to small to moderate holdings. The family rather than the clan now bore the cost of large families.
• Parents were eager for their children to be educated. The government built schools, but parents helped support operating expenses through fees. Studies show this financial pinch changed parents’ attitudes toward contraception and family size.
• A soap opera heard by 40% of Kenyans extolled the advantages of limiting family size.
Organized Efforts to Lower Fertility
There have been a number of approaches in recent years:
• Promote contraceptives (with information on contraception, and the advantages of small families and the disadvantages of larger ones) through all types of mass media, puppet shows, books, posters. The radio has been especially effective, with more than one radio for every three people. Family planning programs in some places and times were voluntary, others offered financial incentives or were even more coercive.
• Develop economies (with the idea that richer people have fewer children). This was also due to a perception among some in the developing world that family-planning was a form of neo-colonialism, or to avoid transfers of wealth from richer to poorer countries.
• Save children, with the idea that lower infant mortality rate, especially among males, will lead to a lower fertility rate. Since this increased population growth, at least in the short term, UNICEF urged “measures of birth spacing and family planning as part of child survival”.
• Empower women who will then prefer smaller families and act on it. This approach often undermines cultural values in societies with high fertility, because girls no longer marry early and have independent lives outside the home.
• Educate men, so that it is much easier for women to use birth control. By 1995, there was little evidence, as the idea was proposed in 1993.
• All of the above. The United Nations International Conference on Population and Development in 1994 offered over 1000 recommendations for voluntary approaches.
So what works?
Which achieves the most per dollar spent? As of 1995, there was no clear answer except “hard times”.
In part 5, Cohen looks at what others were saying in the mid-90s (I’ll discuss only one in any detail) and discusses eight issues which need to be resolved. He also discusses non-population related aspects of the solutions and notes that people often focus on one and ignore the rest. You may wish to follow up by reading more.
Proposals for dealing with population problems confront an intellectual and ideological minefield.
(page 370 Joel Cohen How Many People Can the Earth Support?)
Using a World Bank projection that developing countries could grow from 4.5 billion in 1995 to 10.2 billion in 2100, Bongaarts divided the increase among different causes:
° 2.8 billion to population momentum, as the number of older people changes dramatically over time, see also part 1
° 1.9 billion to unwanted fertility
° 1 billion to a desire for a large family
The first can be reduced to 1.6 billion if age at first birth is increased 5 years. Policy options including raising the legal age to marry, and increasing the amount of secondary education for girls (in one sample of 23 developing countries, women with secondary education gave birth the first time 3.5 years later than women without). Contraception information for adolescents will also help.
In developing countries outside China, one married woman in six had an unmet demand for contraception, and one birth in four is unwanted. This is in addition to a large fraction of the world’s 25 million abortions each year which are illegal, unsafe, or both. Family planning for women and men could help, and could put women and children in contact with health care providers.
The third can be partially addressed by such means as providing education for children, especially when parents are responsible for books, uniforms, and school fees. Improving the status of women has a number of benefits including reducing the need for children for one’s old age. Messages in the media about lifestyles incompatible with large families also help. [Social scientists say that showing men putting on condoms before the ubiquitous sex act on soaps could decrease unwanted pregnancies.]
Reducing the numbers of human beings should not be a goal in itself, but rather a means toward achieving improved human welfare through a more sustainable balance of population and resources, a reduction of disparities in life opportunities, and a realignment of the risks and benefits of reproduction.
(Population Council 1994 publication Population Growth and Our Caring Capacity)
• Academies of Science—Population Summit of the World’s Scientific Academies (1993)
[Note: US National Academies have a Committee on Population]
So what works?
Unfortunately, there appears to be no believable information to show that a dollar spent to put girls through primary school will lower the total fertility rate more, nor a decade from now, than a dollar spent on radio programs about small families or a dollar spent on health clinics for mothers and children or a dollar spent to deliver contraceptives. The experiences…of Indonesia, which had a very rapid fall in fertility from 1970 to 1985, and Kenya, where fertility began to fall in the last half of the 1980s, suggested that well-developed family-planning programs interacted with educational, cultural and economic changes to lower fertility by more than the sum of their separate effects.
(page 377 Joel Cohen How Many People Can the Earth Support?)
Meanwhile, a public conversation can resolve questions on family planning. Eight issues to be decided:
1. How will the bill for family planning and other population activities be distributed between the developing countries (who now pay perhaps 80 percent) and the rich countries?
2. Who will spend the money, and how? How will the available monies be allocated between governments and nongovernmental organizations? how much will go for family planning and how much for allied programs like reproductive health?
3. How will environmental goals be balanced against economic goals? For example, if reducing poverty requires increased industrial and agricultural production in developing countries, can the increases in production be achieved at acceptable environmental costs?
4. How will cultural change be balanced against cultural continuity? In some cultural setting, the goal of empowering women directly contradicts the goal of maintaining “full respect for the various religious and ethical values and cultural backgrounds.” Both goals were often repeated in the final document of the 1994 International Conference on Population and Development. Women achieved the vote in the United States only in 1920 and only after considerable struggle. Asking for equality for women now asks some cultures to make far greater change in far less time. I fully support such demands, but they should be made with a clear and sympathetic understanding that they require profound cultural change.
5. How will the often-asserted right of couples and individuals to control their fertility be reconciled with national demographic goals if the way couples and individuals exercise that right happens not to bring about the demographic goals?
6. How will national sovereignty be reconciled with world or regional environmental and demographic goals? This question arises in the control of migration, reproduction and all economic activities that involve the global commons of atmosphere, oceans and international water bodies, and the management of the plant and animal populations that inhabit them.
7. How will the desire and moral obligation to alleviate poverty and suffering as rapidly as possible be reconciled with the use of local scarcities as an efficient market signal?
8. In efforts to protect the physical, chemical and biological environments provided by this finite sphere, how will rapid population growth and economic development in poor countries be balanced against high consumption per person in the rich countries?
(pages 378-9 Joel Cohen How Many People Can the Earth Support?))
* Population projections:
• International Institute for Applied Systems Analysis (IIASA) through 2100, including a low fertility path that shows population peaking this half century, or a few years later.
• United Nations (pdf) through 2300 (they acknowledge that large unknowns, such as climate change, make projections suspect)
• US Census through 2050
• World Bank through 2050
What People are Saying
part 1—Climate change is a concern: yes or no?
part 2—Cap and trade for greenhouse gas: yes or no?
part 3—Choosing technologies/ changing behavior
part 4—What People are Saying—Population reduction has to happen first, part 1