Our population predicament: a new look

Issued to mark the Population Reference Bureau's 50th anniversary, this issue updates the story of world population presented in its popular predecessor of 1971, "Man's Population Predicament." Estimated at 1/2 billion in 1650, world population reached about 2 billion in 1930, 4 billion in 1975, and is projected to be about 6 billion in 2000. Most of today's rapid growth is occurring among the 3/4 of the world's peoples living in less developed countries where the post-World War II gap between high birth rates and falling death rates has only recently begun to narrow. This growth, coupled with high consumption in developing countries, is putting tremendous pressures on the Earth's resources, environment, and social fabric. New evidence on Europe's population transition and from China, Indonesia, and Thailand in the 1970s suggests that well-designed family planning programs can speed fertility decline but rapid worldwide attainment of replacement level fertility will also require special development efforts and measures that go beyond family planning. Current projections of the world's ultimate peak population range from 8 billion in the mid 21st century to 11 billion in about 2125, depending on when replacement-level fertility is reached. China's drive for a drastic birth rate reduction and the oil crisis might change fertility behavior more rapidly than most demographers have heretofore thought likely.     

Planet earth 1984-2034: a demographic vision

In recognition of 1984 as the year of both Orwell's famous futuristic novel and the International Population Conference following up the 1974 World Population Conference, this Bulletin examines the current state of world population and presents the author's speculations on what it might be 50 years from now. World population, now close to 4.8 billion and growing at 1.8%/year, is being shaped by 3 demographic phenomena: prolonged below-replacement fertility in developed nations, perhaps partly in response to the reduced need for workers in the emerging information era; rapid growth despite failing fertility in developing nations, due to earlier rapid mortality decline; and rapid urbanization in developing nations and unprecedented migration from poor to better-off nations. The author's assumptions for nondemographic factors related to population change in the next 50 years are no world war, nuclear or otherwise; global resource adequacy; rapid scientific and technological progress shared equitably; and the demise of capitalism and communism and greatly increased economic aid from advanced to less advanced nations. For 2034 the author envisages nations divided into service/information societies (4% of global population) where immigration balances low fertility to prevent population decline; industrialized nations (38% of total), with fertility close to or at replacement level and growth slowing; developing nations (43%), in sight of replacement level fertility; and least developed nations, with still critical demographic problems but only 15% of the world population. Total population will be 8.03 billion, but growth will be down to 0.8%/year and global zero growth is possible in another 50 years. This relatively optimistic scenario for 2034 will only be possible if mankind acts to see that the stated nondemographic assumptions are borne out.     

The global and regional impact of mortality and fertility transitions, 1950-2000

During the second half of the twentieth century, world population grew at a record pace, both in absolute and relative terms, from 2.5 billion to 6 billion (or 1.75 percent annually). Demographers have long identified rapid mortality declines as the main explanation. This article finds that one-fourth of today's world population is alive because of mortality improvements since mid-century. Very rapid growth is unlikely to continue as substantial fertility declines also occurred in recent decades. This article finds that already by the year 2000, these fertility declines have almost exactly compensated for the impact of mortality declines from mid-century levels. This result may suggest homeostasis, but analyses of underlying trends contradict this impression. First, the impact of fertility declines will soon and significantly exceed that of mortality declines. Second, that mortality and fertility declines jointly affect the size of the world population by less than one percent conceals a significant impact on the population's age composition as well as on regional population sizes.     

非洲的人口动态与分布

非洲的人口动态长期以来具有高出生率、高死亡率的特点,20世纪90年代以后,非洲的人口动态由高出生高死亡模式向高出生中死亡模式转变．死亡率的持续下降在很大程度上是由于数种过去危害最严重的急性传染病基本上得到有效控制的结果。正是死亡率的下降和持续的高出生率导致非洲人口迅速增长。在非洲人口增长的过程中．人口分布是极不平衡的。非洲人口分布的变化与经济因素的人口定期迁移是密切相关的,大致可分为三种情况．这种独特的迁移模式均与经济活动和生产方式直接相关。     

The outlook of China's population after the stabilization of birth policy

A professor of the Institute of Population Research of the People's University of China attempts to project the future population development of China so that stabilization of the birth policy can be assessed. He divides China into the economically developed and population-controlled area (29% of the population), the economically subdeveloped and population fairly-controlled areas (59% of the population), and the economically less-developed areas where fertility is high (12% of the population). China's population is expected to increase because of the baby boom to 1.25-1.3 billion by the year 2000. Between 1996 and 2000, the growth rate is expected to decelerate and reach zero growth. After 2010, if growth is held at the replacement rate of 2.1, the population will still continue to grow slowly. Around 2100, China's population should be around 1.45-1.59 billion. This would cause a decrease of 27% of arable land. With a decline in fertility rate comes a rise in the amount of the aged population (4.9% in 1982 vs. 5.5% in 1987). The proportion of aged citizens is expected to rise with the stabilization policy until around 2040 where it can be held at about 18%. China's GNP by the year 2000 is expected to be US$1183.8 billion with the per capita GNP about US$934 (providing the population is controlled). Compare this figure with the per capita GNP of the world (US$30,100) and of developed countries (US$10,700) in 1988, and one can see that China is far behind the rest of the world in economic growth.     

世界主要国家人口与经济的发展状况分析

2000年世界人口已经达到60.5亿,80.38%集中在发展中国家,而据预测,到2025年,这一比例会进一步上升到84%,2050年上升到87%以上.世界人口的60%集中在10个人口在1亿以上的人口大国中.发展中国家人口的快速增长,已经或正在吞食着其经济发展的成果,使得人均收入水平难以提高.     

The United Nations on World Population in 2300

The Population Division of the United Nations biennially issues detailed population estimates and projections covering the period 1950–2050. The most recent revision of these estimates and projections, the 2002 assessment, was released in February 2003. At irregular intervals, the Population Division also publishes long‐range projections. The most recent of these, covering the period up to 2150, was issued in 2000, based on the 1998 assessment. On 9 December 2003, the Population Division released the preliminary report on a new set of long‐range projections, dovetailing with the 2002 assessment, that extend over a much longer time span: up to 2300 ( http://www.un.org/esa/population/publications/longrange2/longrange2.htm ). Unlike previous long‐range projections, which, apart from China and In‐dia, were prepared for large regional groupings only, the new projections are elaborated separately for 192 countries. Given the enormous uncertainties of the character of demographic trends over such an extended period, the information content of these projections is somewhat elusive. However, they are expected to be used to provide the demographic input for long‐range models of global climate change. Long‐range population projections also serve to demonstrate the unsustainability of certain seemingly plausible assumptions as to the future course of particular demographic parameters. In the present case, for example, the high‐fertility projection, reflecting a sustained total fertility rate at the relatively modest level of 2.35, by 2300 would yield a population of some 32 billion in the countries now classified as less developed. Or, in a yet more extreme exercise 0/reductio ad absurdum, maintaining constant fertility at present rates would result in a population size of some 120 trillion in the countries now classified as least developed. Apart from the “high fertility” and “constant fertility” models just cited, the projections are calculated for three additional instructive variants: “low fertility,”“medium fertility,” and “zero growth.” Underlying each of the five variants is a single assumption on mortality change: expectation of life at birth creeping up, country‐by‐country, to a 2300 level ranging between 88 and 106 years. International migration is set at zero throughout the period 2050‐2300 in each variant. Thus the projections are unabashedly stylized and surprise‐free, providing a simple demonstration of the consequences, in terms of population size and age structure, of clearly stated assumptions on the future course of demographic variables. Reproduced below is the Executive Summary of the preliminary report on the UN long‐range projections presented to a UN technical working group on long‐range projections at its December 2003 meeting in New York and slightly revised afterward. A full final report on this topic by the Population Division of the Department of Economic and Social Affairs of the United Nations Secretariat will be published later in 2004.     

Population growth,economic development and family planning

This report discusses research conducted to determine whether reduction in population growth rates contributed to the rapid economic growth of Indonesia, South Korea, Japan and Thailand. The 5-year research projects, jointly sponsored by the UN Fund for Population Activities, the Nihon University Population Research Institute, and the East-West Population Institute, concluded that development and family planning programs contributed substantially to fertility decline in these countries. The project examined 3 factors that influence the long-term productive capacity and growth of the 4 Asian economies: savings, the size of the labor force, and the quality of labor (measured by educational attainment). Available evidence indicates a strong positive contribution of population decline toward growth of savings, a growth in labor force concurrent with a decline in fertility rates which enables per capita income to rise, and an increase in 2ndary education enrollment ratios as fertility is lowered. Development factors by themselves explain no more than 1/2 of the decline in fertility observed, suggesting that family planning programs particularly in Thailand, South Korea and Indonesia since 1976 have had an important impact on fertility and economic development.     

Completing the Demographic Transition

Despite ongoing declines in fertility in many countries, the population of the world is experiencing a period of rapid expansion, and its size is expected to reach 10 billion by the end of the demographic transition. Three causes of this growth are identified and quantified: 1) fertility above the replacement level of two surviving children per woman, 2) continuing declines in mortality, and 3) population momentum resulting from a young age structure. A set of simple analytic expressions is proposed for estimating these factors from standard demographic indicators. Population momentum is shown to be the main cause of future growth in most countries and regions.     

The evaluation of China's population policy]

China's population policy has had tremendous effects on the reduction of fertility. The impact of the population policy is manifested in the following aspects. 1) Reducing the size of the total population by 200 million in 17 years. If the population growth rate had remained at its 1970 level of 2.6/1000, the total population would have been 1.28 billion in 1987. 2) The implementation of the population policy accelerated the process of demographic transition. The mortality decline which began in the early 1950s initiated the demographic transition. The Fertility decline began after the birth control policy was implemented and shifted the transition to a low population growth stage even before the socioeconomic conditions which are considered to be the determinants of fertility decline appeared. The fertility decline, in turn, promoted the socioeconomic development of the country. 3) Solving the problem of food; feeding 21.6% of the world's population on 7.1% of the world's farm land is no easy task. The success of population control, no doubt, played an important role in lowering the population growth rate so that the growth of food production could keep pace with the needs of the population. 4) A decline in the dependency ratio is a favorable condition to socioeconomic development. China's dependency ratio of 59.7 is among the lowest in developing countries and is close to the level in developed countries. Therefore, more production output can be used in investment rather than consumption. 5) The fertility decline facilitated a balanced economic growth. The ratio of population growth as compared to the growth of major economic indicators should be considered an important issue in maintaining macroeconomic control. The population policy made it possible for economic growth to surpass population growth.     

Quality of life declines in big and growing cities. Poverty in cities

The quality of life in developing countries during the first couple of decades after the Second World War was higher in cities than in small towns and villages. However, the relative advantage of city dwellers in developing countries has declined since the 1970s, with high-growth rate cities experiencing a more severe decline. Infant mortality levels in Latin America and sub-Saharan Africa in the 1990s are as high in large cities as in the smallest towns and villages. In most developing regions, big city residents are increasingly disadvantaged, such that researchers and policymakers can no longer assume that the quality of life in urban areas is better than in rural areas. The urban transformation of the developing world is similar to the 19th century urbanization of now-developed countries, but today many more people are crowding into far bigger cities. Using survey information from 43 countries representing 63% of the developing world's urban population outside of China and India, Martin Brockerhoff of the Population Council and Ellen Brennan of the UN Population Division found that rapid population growth and big size have overwhelmed the capacity of cities to provide essential goods and services.     

中国少数民族人口发展形势分析

一、人口数量 20世纪80年代,中国少数民族人口一度高速增长,从1982年的6643万人增至1990年的9057万人,年均增长率达到3．89％,占全国人口的比例从6．62％提高到8．01％。1990—2000年,根据“五普”资料,全国（大陆）人口增加了9．92％,其中,汉族人口由103919万人增至113739万人,增加了9．45％,全国人口和汉族人口年均增长率分别为0．91％和0．87％;     

Demographers’ Involvement in Twentieth-Century Population Policy: Continuity or Discontinuity?

The second half of the twentieth century witnessed the development of a crusading spirit and massive technical aid aimed at reducing fertility levels and rates of population growth in developing countries, and also the involvement of demographers in these events. The demographers at Princeton University’s Office of Population Research, Frank Notestein and his colleagues, have been singled out by recent authors as playing a unique role in bringing about these changes, and they have been criticized for encouraging demographers to become involved, so eroding their scientific objectivity. This paper examines the development of relevant population thought and theory in the English-language literature over the first half of the twentieth century. It concludes that in the circumstances of the second half of the twentieth century, it was inevitable that developed countries and their demographers would become involved in controlling fertility levels in developing countries. The OPR story should be seen largely in terms of how the world’s leading demographic center and its demographic transition theory were swept along by global changes. As those developments started, attitudes to population change in densely settled Asia became Malthusian, even as population growth accompanied by mortality decline in Asia demonstrated that, at least in the short term, the positive checks were disappearing.     

China's population policy: A model of a constant stream of births

The current population policy of China, which emphasizes one child per family, is facing considerable challenge brought about by socioeconomic reforms. The principal challenge is greater individual freedom created by the reforms. The present article examines this conflict.Based on cohort-period fertility analysis, the author proposes a policy of a constand stream of births which ensures a moderate growth rate and a smooth age structure while enabling each couple to have at least two children. Simulation suggests that, in order to achieve the two goals of limiting population size (to about 1.2 billion in 2000 and 1.4 billion in the 2050s) and allowing more individual fertility choice (2.2 children per family), the annual stream of births should be around 20 million and the mean age of childbearing has to increase from 26 to 30 over the next 10–15 years.The author concludes that, if the policy proposed here succeeds, some social and economic problems associated with the conflict between the reforms initiated by the government and its one-child policy will be mitigated.Paper presented at the 1989 meeting of the Population Association of America.     

China's demographic dilemmas

The year 2000 marks the end of a tumultuous century in China's population history, which weathered the demographic effects of devastating famines, wars, and epidemics and population growth and change. This paper examines the effect of population policies on the demographic dilemmas of China. In the 1950s, China had seen the fastest demographic transition in history, with a dramatic decline in mortality rates, followed by a decrease in fertility rates. However, in the 1970s, revisions in population control measures, changes in age structure, and fluctuations in age at marriage resulted in lower fertility rates. The struggles encountered by China in regulating fertility are described; these include the different methods of birth control, gender preference, marriage, population aging, and minority populations. Population and development issues within the context of urbanization, employment, education, health care, economy, and environment are also discussed. Future implications of these findings indicate the need for a systematic, effective, and complete environmental clean-up, as well as fertility and population policies.     

D. V. Glass on the Problems of a Declining Population

During the past quarter century fertility has dropped below replacement levels in many parts of the world. According to United Nations estimates, in 2005 this was the case in 65 countries, comprising 43 percent of the world's population. In many cases, most notably in Europe and East Asia, the shortfall of fertility from the level that would be necessary in the long run to sustain a stationary population is substantial. In Europe, for example, the average total fertility rate for the period 2000–2005 was 1.4. Indefinite maintenance of such a level implies a shrinkage of the total population by one‐third over a generation–roughly every 30 years. Accompanying that rapid decline of total numbers would be an age structure containing a preponderance of the elderly, posing extreme adjustment difficulties for the economic and social system. Societies that wish to avoid radical depopulation would have to engineer a substantial rise infertility–if not to full replacement level (slightly more than two children per woman), then at least to a level that would moderate the tempo of population decline and make population aging easier to cope with. An additional counter to declining numbers, if not significantly to population aging, could come from net immigration. This is the demographic future assumed in the UN medium‐variant projections for countries and regions currently of very low fertility. Thus, for example, in Europe over the period up to 2050 fertility is assumed to rise to 1.85 and net immigration to amount to some 32 million persons. The UN projections also anticipate further improvement in average life expectancy–from its current level of 74 years to 81 years. This factor slows the decline in population size but accelerates population aging. Under these assumptions, Europe's population would decline from its present 728 million to 653 million by 2050. At that time the proportion of the population over age 65 would be 27.6 percent, nearly double its present share. Demographic change of this nature is not a novel prospect. It was envisioned in a number of European countries and in North America, Australia, and New Zealand in the late 1920s and early 1930s. Concern with the possible economic and social consequences generated much discussion at that time among demographers and social scientists at large and also attracted public attention. Possible policy measures that might reverse the downward trend of fertility were also debated, although resulting in only hesitant and largely inconsequential action. The article by D. V. Glass reproduced below is an especially lucid and concise treatment of demographic changes under conditions of low fertility and their economic and social implications. It appeared in Eugenics Review (vol. 29, no. 1, pp. 39–47) in 1937 when the author was 26 years old. Glass's line of argument is broadly representative of the main focus of demographic analysis in the mid‐1930s on aspects of population dynamics, applying the then still novel analytical tool of the stable population model. It also echoes the work of economists then witnessing the great difficulties capitalist economies faced in adjusting to structural changes in consumer demand and labor supply. While Glass addresses these issues primarily with reference to England and Wales, he sees the issues as affecting all industrialized countries. The Malthusian problem of relentless population growth he persuasively declares to be irrelevant for these countries. The Western world faces the opposite problem: population decline, a trend only temporarily masked by the effects of an age distribution that still has a relatively high proportion of women in the child‐bearing ages, reflecting the higher fertility level of the past. A stationary population, Glass cogently argues, is to be welcomed, and he considers the absolute size at which zero growth would be achieved relatively unimportant. In contrast, a continuous population decline would have “thoroughly disastrous” results in an individualist civilization and in “an unplanned economic system.” And, he concedes, somewhat quaintly, that sustained below‐replacement fertility would pose a great problem “even in a country in which the means of production were owned communally.” Glass's conclusions about the reversibility of low fertility are as pessimistic as those of most informed observers today. Still, he sees hope in a future “rationally planned civilization” that would “produce an environment in which high fertility and a high standard of life will both be possible.” In this context, high fertility means the level necessary to sustain the population in a stationary state. By present‐day standards the level Glass calculates as needed for long‐term zero growth is indeed fairly high: 2.87 children per woman. But that figure reflects the fact that, when he wrote, mortality up to age 50 was still fairly high and fertility occurred almost wholly within marriage; it also assumes zero net immigration. In the last 70 years much has changed in each of these three components of population dynamics, both in England and Wales and in the rest of Europe. Still, Glass's commentary remains highly relevant to the discussion of the problems of low fertility today. David Victor Glass (1911–78) was associated with the London School of Economics throughout much of his scientific career. He followed R. R. Kuczynski as reader in demography in 1945 and became professor of sociology in 1948. His work on demography, population history, and population policy had already made him one of the most influential demographers in pre‐World War II Britain. After the war he rose to international prominence through pioneering work on the Royal Commission of Population; through his research on historical demography, the history of demographic thought, and social mobility; and through founding, in 1947, the journal Population Studies, which he edited until his death.     

Birth rates decline as neighbors learn from one another how to control fertility

This article refers to a recent article (by Population Council demographer John Bongaarts and University of Pennsylvania sociology professor Susan Cotts Watkins) on strategies for promoting future global fertility decline. The article emphasizes the importance of the process of social interaction as a powerful force that accelerates the pace of demographic transition. The force of social interaction is frequently overlooked. Social interaction operates through personal networks that connect individuals; national channels of interaction connecting social and territorial communities within a country; and global channels connecting countries. Empirical evidence finds that the most important interaction for fertility change occurs in exchanges between personal networks of small communities. When innovative fertility behavior is adopted by a group within a community, then changes are communicated in an ever widening band. It is expected that countries with multiple channels of linked transportation and communication networks and extensive media facilities would experience more rapid fertility decline. Bongaarts and Watkins argue that the extent of a country's links with a global society help determine the timing of its transition to lower fertility. All countries are connected to some extent by ideas, information, or social influence and are at some level of development. When some countries in a region begin their fertility transition, neighboring countries soon follow. Fertility transition occurs even at low levels of development. Fertility decline can occur rapidly, even if socioeconomic development is modest, once the onset of the transition has occurred.     

Asian and Pacific population targets

2 population targets for the Asian and Pacific regions were established in 1981-82: 1) by the Asian Conference of Parliamentarians on Population and Development at Beijing, China to attain 1% population growth rate for the Asian region by the year 2000, and 2) by the 3rd Asian and Pacific Population Conference at Colombo, Sri Lanka, to attain replacement level of fertility by the year 2000. In an attempt to ascertain whether these targets can be achieved and/or related, the Population Division of the UN's Economic and Social Commission for Asia and the Pacific (ESCAP) prepared population projections in which the 2 targets are achieved. These projections were prepared by aggregating the total population of member countries. When net reproduction rate (NRR) equals 1 (replacement level fertility) it will lead to a stable population with a growth rate of zero. In the short-term a population with replacement level fertility will continue to increase if it has a young age structure due to previous higher levels of fertility. Some projections for the period 1980-2005 are: 1) population growth rate will decrease from 1.78% to 1.05%, 2) total fertility rate will decrease from 3.63-2.11, 3) male life expectancy will increase from 59.8-67.3, and 4) infant mortality rate will decrease from 67.3-34.5. For the ESCAP region, a target of NRR of 1 would be easier to achieve than a growth rate of 1%. The UN projects the total population of the region to be 3,382,000,000 in the year 2000. If the NRR can be lowered to 1 by then, however, the total population would be 3,342,000,000 and if the growth rate can be reduced to 1% by the end of the century the resulting population would be 3,300,000,000. Major demographic benefits will be attained in terms of the age structure of the population if a 1% growth rate is achieved; the proportion under age 15 was 37.1% in 1980 but will be 27.2% in 2000 with a dependency ratio of 48.8 compared to 70.8 for 1980.     

The UN Population Division on Replacement Migration

The most salient demographic trend pictured by the influential set of population projections prepared by the Population Division of the United Nations (a unit in the UN's Department of Economic and Social Affairs) is the continuing substantial increase—albeit at a declining rate—of the global population during the coming decades. According to the “medium” variant of the most recent (1998) revision of these projections, between 2000 and 2050 the expected net addition to the size of the world population will be some 2.85 billion, a figure larger than that of the total world population as recently as the mid‐1950s. All of this increase will occur in the countries currently classified as less developed; in fact, as a result of their anticipated persistent below‐replacement levels of fertility, the more developed regions as a whole would experience declining population size beginning about 2020, and would register a net population loss of some 33 million between 2000 and 2050. A report prepared by the UN Population Division and released on 21 March 2000 addresses some of the implications of the changes in population size and age structure that low‐fertility countries will be likely to experience. The 143‐page report, issued under the eyecatching title Replacement Migration: Is It a Solution to Declining and Ageing Populations?, highlights the expected magnitude of these changes by the imaginative device of answering three hypothetical questions. The answer to each of these questions is predicated on the assumption that some specified demographic feature of various country or regional populations would be maintained at the highest level that feature would exhibit, in the absence of international migration, in the United Nations' medium population projections (as revised in 1998) during the period 1995–2050. The selected demographic features are total population size, the size of the working‐age population (15–64 years), and the so‐called potential support ratio: the ratio of the working‐age population to the old‐age population (65 years and older). The illustrative device chosen for accomplishing the specified feats of preserving the selected demographic parameters (i.e., keeping them unchanged up to 2050 once their highest value is attained) is international migration. Hence the term “replacement migration.” Given the low levels of fertility and mortality now prevailing in the more developed world (and specifically in the eight countries and the two overlapping regions for which the numerical answers to the above questions are presented in the report), and given the expected future evolution of fertility and mortality incorporated in the UN population projections, the results are predictably startling. The magnitudes of the requisite compensatory migration streams tend to be huge relative both to current net inmigration flows and to the size of the receiving populations; least so in the case of the migration needed to maintain total population size and most so in the case of migration needed to counterbalance population aging by maintaining the support ratio. Reflecting its relatively high fertility and its past and current record of receiving a large influx of international migrants, the United States is a partial exception to this rule. But even for the US to maintain the support ratio at its highest—year 1995—level of 5.21 would require increasing net inmigration more than tenfold. The country, the report states, would have to receive 593 million immigrants between 1995 and 2050, or a yearly average of 10.8 million. The extreme case is the Republic of Korea, where the exercise calls for maintaining a support ratio of 12.6. To satisfy this requirement, Korea, with a current population of some 47 million, would need 5.1 billion immigrants between 1995 and 2050, or an average of 94 million immigrants per year. (In the calculations, the age and sex distribution of migrants is assumed to be the same as that observed in the past in the main immigration countries. The fertility and mortality of immigrants are assumed to be identical with those of the receiving population.) The “Executive Summary” of the report is reproduced below, with the permission of the United Nations. Chapters of the full report set out the issues that prompted the exercise; provide a selective review of the literature; explain the methodology and the assumptions underlying the calculations; and present the detailed results for the eight countries and two regions selected for illustrative purposes. A brief discussion of the implications of the findings concludes the report. As is evident even from the figures just cited, immigration is shown to be at best a modest potential palliative to whatever problems declining population size and population aging are likely to pose to low‐fertility countries. The calculations, however, vividly illustrate that demographic changes will profoundly affect society and the economy, and will require adjustments that remain inadequately appreciated and assessed. The criteria specified in the UN calculations—maintenance of particular demographic parameters at a peak value—of course do not necessarily have special normative significance. Past demographic changes, with respect notably to the age distribution as well as population size, have been substantial, yet they have been successfully accommodated under circumstances of growing prosperity in many countries. But the past may be an imperfect guide in confronting the evolving dynamics of low‐fertility populations. As the report convincingly states, the new demographic challenges will require comprehensive reassessments of many established economic and social policies and programs.