UNFPAState of World Population 2002
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C H A P T E R   2
Population Change and People's Choices

Population Continues to Grow, and to Grow Older

At the beginning of the 20th century, the world’s population was approximately 1.5 billion; by 1960 it had doubled; and by late 1999, it had quadrupled to 6 billion. The global population is unlikely ever again to grow as fast as it has in the last few decades and particularly the past 12 years, in which a billion people were added.

Annual additions to the global population rose from 47 million per year in 1950–1955 to a peak of 86 million in 1985–1990. This unprecedented growth was the net result of faster declines in mortality than in fertility, both from initially high levels. As a consequence, the fourth, fifth and sixth billion marks in global population were achieved in only 14, 13 and 12 years, respectively.3

Today, a "demographic transition" from high fertility and mortality to low fertility and mortality is under way or has already occurred in much of the world. In many respects, the less-developed regions are now about halfway through this transition, approximately where the more-developed regions were a half-century ago.

Death Rate Cut by Half
The most important story behind the rapid rise from 3 to 6 billion people since 1960 is the unprecedented drop in mortality. This trend actually began in the 19th and early 20th century, but intensified after World War II as basic sanitation, clean drinking water and modern health care became more available in larger areas of the world. Since 1950, the death rate has been cut in half, from about 20 to fewer than 10 deaths per year per thousand people. At the same time, average global life expectancy has risen from 46 to 66 years.

The world’s population is healthier from infancy through old age than it ever has been. Global infant mortality has fallen by two thirds since 1950, from 155 per thousand live births to 57 per thousand; this rate is projected to be reduced by a further two thirds by 2050. Maternal mortality has also declined, but much more slowly and less generally (see Chapter 3). Other promising health trends include improvements in immunization levels and health education.

One positive effect of lengthening life-spans and better medical treatment has been that the annual number of deaths actually fell by more than 10 per cent between 1955 and 1975 even as nearly 1.5 billion people were added to the world population. Subsequently the number of deaths began to increase. The current number of deaths per year, 52 million, is the same as in 1950, when the population was less than half the size it is today.

Death rates have declined substantially in the less-developed regions since 1950, but have remained roughly constant in the more-developed regions because of their greater proportion of older people.

Fertility is Declining, but Unevenly
The number of births per year rose from 98 million in 1950 to a peak of 134 million in the late 1980s, and is projected to remain just under 130 million for the next 20 years while death rates slowly rise as the global population ages.

Although only a very few countries have declining populations, 61 countries (with about 44 per cent of the world’s population) already have below-replacement fertility rates (less than 2.1 births per woman). The number of such countries is projected to grow to 87 by 2015, encompassing about two thirds of the world’s population.

On the other hand, in 2050, 130 countries will still have positive growth rates, 44 of them above 1 per cent per year, about the rate observed in more-developed regions in 1965.

In 1950-1955, the average fertility rate in the more-developed regions was 2.8 children per woman; it has since dropped to 1.6 and is projected to begin a slow rise, to 1.8, by the middle of next century. In the less-developed regions, the fertility rate was almost 6.2 in 1950; it was slightly less than 3 by 1999, and is projected to fall to less than 2.1 by 2045.

Death rates have fallen by half since 1950,
accounting for much of the rapid growth of world population.

Fertility has declined most quickly in Latin America and Asia, less rapidly in North Africa and the Middle East, and much more slowly in sub-Saharan Africa. Asia’s fertility fell sharply in the last 50 years, from 5.9 to 2.6 children per woman. Sub-Saharan Africa’s has dropped much more slowly, from 6.5 to 5.5. Latin America and the Caribbean have seen a decline from 5.9 to 2.7, North Africa and Western Asia from 6.6 to 3.5.

Europe’s fertility rate fell from 2.6 to 1.4, well below replacement level. On the other hand, Northern America’s fertility fell from 3.5 in 1950-1955 to 1.8 in the late 1970s, and then rebounded to the 1.9 to 2.0 range, where it has remained. It is projected to stay around 1.9 to the middle of the 21st century.

Variations between and within regions, and among different population groups within countries, remain considerable. Some nations, such as Brazil and the Republic of Korea, have moved swiftly to near-replacement level or below; others, such as Nigeria and Guatemala, have seen only a slight fall in fertility rates. However, the pace of decline has varied dramatically in different parts of both Brazil and Nigeria.

Hopes of finding a simple and consistent explanation for the demographic transition 4 have been repeatedly dashed by the realities of data on local experiences.5 In fact, there is no tight statistical link between development indicators and fertility rates, and the reasons for fertility decline are widely debated by demographers, economists and policy makers. While development is still considered an important factor, it remains unclear why fertility transitions occur earlier in some places than others. The pace of development does not appear to affect the initiation or the rate of fertility transition. However, once a transition has begun, fertility declines more rapidly in countries with higher levels of development.6

Helping women and men to realize their family size desires
It seems clear that the family size desires of men and women are influenced by a variety of factors: mortality declines; increased social opportunity, especially for women; employment opportunities; incomes; and educational access. Women and men cannot realize these desires, however, without the means to translate social opportunity and choice into action. The creation and progressive strengthening of population programmes over the last 30 years 7 — along with the development and distribution of more-effective and safer forms of contraception — has been a crucial catalyst in reducing fertility rates.8 Population programmes have been given credit for about half the decline in fertility since 1960. 9
Since the ICPD, they have adopted an approach based on individual rights and needs.

Population programmes have been crucial
in reducing fertility rates in the past 30 years.

The spread of information about family planning techniques and new ideas about social issues — including the rights of women to reproductive health and equality of opportunity — facilitates the fertility transition.10 Discussion and debate among relatives, friends and neighbours, the diffusion of ideas between communities, and mass media images trigger changes in preferences and fertility behaviour. This may explain why fertility changes often occur more rapidly in countries where various channels connect communities and individuals, and more slowly where such social interaction is more difficult. If this is the case, improving communications could help to speed up the fertility transition where it has been slow.11

Predicting what will happen at the end of the fertility transition in a particular country — whether fertility will stabilize at below, near or above replacement level, or will bounce back upwards or have some other unstable pattern — remains a critical challenge for demographers.

Lower Population Projections:
Good News and Bad

The United Nations Population Division’s latest projection for global population in 2050, 8.9 billion (medium variant), is substantially lower than its 1996 projection of 9.4 billion. In response, some commentators have raised concerns about "missing" people. This is misleading.

The major reason for the lower projection is good news: global fertility rates have declined more rapidly than expected, as health care, including reproductive health, has improved faster than anticipated, and men and women have chosen to have smaller families.

About one third of the reduction in long-range population projections, however, is due to increasing mortality rates in sub-Saharan Africa and parts of the Indian subcontinent. The most important factor is HIV/AIDS, which is spreading much faster than previously anticipated.

In addition, United Nations demographers have adopted more refined projection techniques. Formerly, it was assumed that countries with below-replacement fertility rates would return to replacement levels by 2050. The current assumption is that these countries will have fertility rates of 1.7 to 1.9 births per woman (rather than 2.1) by 2050.

Changing assumptions about future fertility
In late 1998, the United Nations Population Division released its latest population projections for the world, regions and countries through 2050 (see page 3). The Population Division produces new projections every two years based on updated population data and revisions in projection methodology. In the case of the 1998 Revision, both factors had a substantial impact on the long-range projections.12

It is now projected that the global population will rise to between 7.3 and 10.7 billion by 2050; the medium variant projection, considered most likely, is 8.9 billion. The key assumptions that create these results are global fertility rates, which are projected to fall to between 2.5 and 1.6 births per woman by 2050. Under the medium variant scenario, it is assumed that the fertility rate for every country in the less-developed regions will drop to exactly 2.1 by 2050. For the more-developed regions, national fertility rates are projected to reach between 1.7 and 1.9, depending on the country.

These assumptions point out the inherent uncertainties of population projections. The United Nations projections have a record of successive adjustment to new information and considerable long-term accuracy. However, it does not seem very likely that the Congo, Nicaragua and Kazakhstan, with current fertility rates of 6.1, 4.4, and 2.3 births per woman, respectively, will all have identical fertility rates of 2.1 in 2050. Similarly, it is by no means certain that Italy’s fertility rate will rise from 1.2 to 1.7, or the United States’ rate will drop from 2.0 to 1.9 by 2050, as the medium variant projection assumes. National fertility rates will remain unpredictable over the long run. Demographers, at institutions including the United Nations, are undertaking analyses to improve or place scientific certainty bounds around projection scenarios.13

Education Levels and Fertility Declines
Throughout the developing world, literacy and years of schooling have increased for both males and females over the last four decades.14 Demographers and sociologists have observed that improved education for women and girls is closely related to improvements in health and to falling fertility rates.

Enrolment ratios have increased since 1960 in all regions and at all education levels, especially at the primary level. 15 In sub-Saharan Africa, however, primary school enrolment was still only 75 per cent in 1995 and has actually decreased since 1980. Enrolment has also declined recently in other countries affected by financial crises.16

In low- and middle-income countries, 53 per cent of the relevant age group were enrolled in secondary schools in 1995, up from 41 per cent in 1980. This compares poorly with the high-income countries, where virtually all children have some secondary education, and 35 per cent have some tertiary education (college and graduate school).

The limited data available on years of schooling illustrate the stark contrasts that persist. For instance, in Burundi, men and women have had, on average, 5 and 4 years of schooling, respectively. In Costa Rica, those numbers are 10 and 9 years, respectively; in Canada, 18 and 17 years.

There is still a significant gender gap among both teachers and pupils in low-income countries, but the situation is improving: 42 per cent of students in 1980 were female, 44 per cent in 1995; 32 per cent of teachers in 1980 were female, 39 per cent in 1995. In middle- and high-income countries, the gender balance for pupils and teachers is much closer — men still outnumber women in both groups, but only by a few percentage points.

To foster the social development of girls, some countries have begun to promote girls’ education through waiving fees, or providing a small payment or food allocation for girls’ attendance, and by adapting the school system to facilitate their participation. Since 1990, the Bangladesh Rural Advancement Committee has, for example, created over 30,000 schools that offer non-formal primary education; 70 per cent of the pupils are girls.17

Recent analyses undertaken for the World Bank 18 reveal significant income-based differentials in child enrolment, and distinct regional patterns of enrolment in poor populations. For example, in Latin America, there is near universal enrolment of the poor in first grade but then substantial dropout grade by grade, while in South Asia and Western and Central Africa the poor mostly do not enrol.

Differences between the rich and the poor in median years of schooling completed vary considerably across countries, ranging from only one year to as many as 10. The effect of adult income levels exceeds male-female differentials in many settings.19 Poor girls, however, suffer from a double disadvantage that can severely restrict their opportunities.

Nearly one out of four adults in the world, around 1 billion people, cannot read, write or do simple arithmetic.20

FIGURE 2:  Educational Attainment by Gender, Region

Education leads to smaller, healthier families
One of the strongest and most consistent relationships in demography is between mothers’ education and infant mortality — the children of women with more years of schooling are much more likely to survive infancy. 21 More-educated mothers have better health care, marry later and are significantly more likely to use contraception to space their children. They have better skills for obtaining and evaluating information on health care, disease prevention and nutrition. They also have better access to resources, through earning opportunities and marriage, and can manage them better. They are more likely to recognize the advantages of educating their children.

The relationship between women’s education and fertility is also complex, but the underlying pattern in most countries is that the more years of schooling a woman has, the fewer children she is likely to have. In a small number of countries, particularly in sub-Saharan Africa, fertility rises slightly with the first few years of women’s schooling, then falls with subsequent years of education. 22 In all recent studies, additional secondary education for women correlates with lower fertility.

Educated women are more likely to use
contraception and tend to marry later.

Educated women are more likely to use modern methods of contraception, and they tend to marry later. Educated parents of both sexes also generally desire smaller families than those with less education, and educated women tend to act on that reproductive preference for fewer children. In other words, women with more schooling are more likely to have the number of children they say they want.23

According to a study of Egyptian families, the educational aspirations that women and men have for their children, particularly their daughters, are significant factors in how many children they desire. Parents who hope for better education for their female children tend to want smaller families, perhaps so that they can provide more fully for the offspring they have.24

Women of all levels of education and economic status take steps to choose the number and spacing of their children. Their ability to do so is a function of not only education, but also circumstance, resources and custom.25 Population programmes help provide the means.

Ageing Populations
A gradual ageing of the global population in the decades to come is all but certain. The reasons for this trend reflect the substantial human progress of this century — lowered infant and child mortality; better nutrition, education, health care and access to family planning; and longer life expectancies.26

This transition is already well under way in the more-developed regions, where the median age has risen from 29 in 1950 to 38 today and is projected to plateau at around 46 by 2050. In the less-developed regions, this process is just beginning; since 1950, the median age has fluctuated between 19 and 24 (its current level). Africa, the world’s most rapidly growing region, is also the youngest, with a median age of only 18. The median age in all the less-developed regions is projected to begin a gradual rise to 37 by 2050.

There is every reason to believe that societies in both the more- and less-developed regions can adjust to the higher median age of their inhabitants and the increasing ratio of old to young people. Yet undoubtedly this new era will present distinct challenges. The world’s people have never been this healthy or lived this long. In 1950, average life expectancy globally was 46 years; in 2050 average life expectancy is projected to be 76, and the median age is projected to be 38.

Countries in more-developed regions are already coming to grips with this unprecedented transition and the issues that it presents with respect to the labour pool, care for the elderly, and the potential for population decline.

Around the world, but particularly in the more-developed regions, countries with ageing populations will face challenges pro-viding support and medical care for the elderly. The percentage of young dependants will decline, but the proportion of older dependants will increase.

The Youth Factor
Today, as a result of high fertility in the recent past, there are more young people than ever — over 1 billion between ages 15 and 24. They are entering their peak childbearing years. In all developing countries, the proportion of the population aged 15-24 peaked around 1985 at 21 per cent. Between 1995 and 2050, it will decline from 19 to 14 per cent, but actual numbers will grow from 859 million to 1.06 billion.

These numbers ensure continued population growth, even if young people choose to have smaller families than their parents had. Indeed, populations would continue to grow for several decades even if "replacement-level" fertility were reached immediately.

This phenomenon, known as "population momentum", will account for up to two thirds of the projected population growth worldwide, more in countries where fertility has fallen most quickly. In Thailand, for instance, where three people out of ten are under age 15, the population is projected to grow by 19 per cent between 1999 and 2025, even though the average couple is having fewer than two children. Raising the average age at which women have their first child from 18 to 23 would reduce population momentum by over 40 per cent.

Globally, lower birth rates create the strong possibility of a "demographic bonus" in the less-developed regions in the next couple of decades, as a "bulge" of young people grow up and become part of the work force while fewer children are born. If enough employment opportunities can be created, these new workers could well result in greater productivity and economic development, and generate substantial revenues for health care, education and social security.27 There is every reason to believe that societies in both the more- and less-developed regions will benefit from this change.

The Impact of AIDS
HIV/AIDS is now the leading cause of death in Africa and the fourth most common cause of death worldwide.28 The Joint United Nations Programme on HIV/AIDS (UNAIDS) estimates that 33.4 million people were HIV-positive as of December 1998 and 2.5 million died of the disease in 1998 — 2 million in Africa. One half of all new HIV infections are in young people between ages 15 and 24.

It is estimated that 95 per cent of those infected live in developing countries, and two thirds live in sub-Saharan Africa, where 8.0 per cent of adults aged 15-49 are HIV-positive. AIDS has a terrible effect on individuals and communities, as it strikes down working people, orphans children, and places huge strains on health care and social systems.

 FIGURE 3: Regional Trends in Age Structure

the global scale, but it will have a devastating impact on several African countries. Because of high fertility rates, most sub-Saharan African countries are still expected to experience population growth, but for the most-afflicted nations the pace will be much slower than it would be without the epidemic.29

Devastating Impact of HIV/AIDS in Africa

New estimates of the prevalence of HIV/AIDS indicate that the epidemic is more serious than was previously thought. Estimates released in 1998 by UNAIDS and the World Health Organization indicate that global HIV infections increased 10 per cent in 1998 to 33.4 million people worldwide. Last year alone, an estimated 5.8 million people contracted the virus that causes AIDS.

Using UNAIDS estimates of the number of people currently infected, the United Nations Population Division last year produced projections of future HIV prevalence rates and the likely demographic impact in 34 of the most-affected countries (29 of them in Africa), accounting for 85 per cent of currently infected persons and 91 per cent of all AIDS deaths to date.

In the 29 African countries, the average life expectancy at birth is currently seven years less than it would have been in the absence of AIDS. The average life expectancy in the nine countries with an adult HIV prevalence of 10 per cent or more (Botswana, Kenya, Malawi, Mozambique, Namibia, Rwanda, South Africa, Zambia and Zimbabwe) is estimated to be 48 years, 10 years less than it would have been in the absence of AIDS. However, the population is not expected to decline in any of these countries.

In Botswana, with the world’s highest HIV/AIDS prevalence rates — one of every four adults is infected — life expectancy has fallen from 61 years in the late 1980s to 47 today, and is expected to plunge to 38 by 2005—2010. Botswana’s population by 2015 may be 23 per cent smaller than it would have been in the absence of AIDS. Nevertheless, because of continuing high fertility, the population is still expected to nearly double between 1995 and 2050.

In Zimbabwe, the second-hardest-hit country, one in five adults is infected. Estimated life expectancy at birth is 44 years and will fall to 41 in 2000—2005, 25 years less than what would be expected in the absence of AIDS. Population growth has fallen to 1.4 per cent; it would be 2.4 per cent without AIDS. Zimbabwe’s population in 2015 is expected to be 19 per cent lower than it would have been in the absence of the epidemic.

The Impact of AIDS in Sub-Sahran Africa:
Population Projections with and without AIDS
in the 29 most-afected Countries, 1980-2050

For a complete view of this chart, please click here

In many countries, AIDS has erased decades of progress in reducing child mortality and increasing life expectancy. In addition to increasing mortality, HIV/AIDS can also affect demographic change by reducing the fertility of women who are infected and influencing age at marriage, sexual behaviour and contraceptive use.

The course of this epidemic, both globally and in particular countries, is still to be determined. There are some hopeful signs — infection and mortality rates are falling in a number of countries, though they are continuing to rise in others. The development of the epidemic in South and East Asia, and particularly in India and China, is a particular cause of concern.30 Slowing and stopping the spread of AIDS will require improvements in comprehensive reproductive health care, as well as better public education about the risks and consequences of HIV infection.

Prospects for Low-fertility Countries
An active debate is under way within the demographic community about the prospects for future fertility in current (and projected) low-fertility countries. There may well be a "bottom" for fertility rates for each society, a point after which rates will begin to rise again, but demographers clearly cannot make that kind of prediction with any certainty.

One school of thought holds that below-replacement fertility is unlikely to persist very long. In this view, projected fertility declines may be overstated because methods of measuring current fertility rates do not capture completed fertility trends when more younger women are delaying child-bearing until later in their lives.31 For instance, in the United States and Sweden, the fertility rate dropped well below replacement in the 1970s and 1980s but rose again to above 2.0 in the early 1990s. On the other hand, the fertility rate in Italy also dropped below replacement in the late 1970s and has continued to fall, reaching 1.2 by the late 1990s.

It is considered significant that completed fertility among those who have any children remains above the replacement level in most European countries. Statements of desired fertility also remain at or above replacement level. Measured fertility declines might stop when the age of marriage ceases to increase unless desired fertility falls.

Another school of thought holds that below-replacement fertility, particularly in Europe, has become well-established and associated with continuing declines in desired family size.32 It is not clear, meanwhile, that all countries will reach below-replacement fertility. In some countries, fertility declines have stalled at levels above replacement level.33


For more information:
United Nations Population Fund
Information and External Relations Division
220 E. 42nd Street, New York, NY 10017, U.S.A.
Tel. 212-297-5020; fax: 212-557-6416
E-mail: ryanw@unfpa.org. Web site: www.unfpa.org