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What Are Age Structure Diagrams?

The age structure of a pop~ation is the proportion of (or of each sex) at each age level. Demographers usually plot percentages or numbers of males and females in the total population in three age categories: preproductive (0-14), productive (15-44) and postproductive (45-85).

How Does Age Structure Affect Population Growth?

A population with many childbearing age women will grow because the total number of births will exceed the total number of deaths even at replacement-level fertility. A population will stop growing (zero population growth) if replacement-level fertility continues long enough (if immigration is not a factor). How long depends on (l)the number of reproductive age, and (2) the number under age 15.

How Can Age Structure Diagrams Be Used to Make Population and Economic Projections?

The 78 million-person increase between 1946 and 1964, known as the baby-boom generation, will continue to move upward through the country's age structure as the members of this group grows older. The number of 52-59 year-olds will grow 50% between 1996 and 2006.

Baby boomers (nearly half of all adult Americans) dominate demand for goods and services, and play an important role in elections. Boomers will create a surplus in the Social Security fund, while working, but will use it up by 2029. A strain on health care has projected the Medicare fund will run out of money by 2001

The baby-bust generation - born since 1965 (when fertility rates dropped), will have the economic burden of supporting retired baby boomers. Retired baby boomers may use their political clout to force the baby-bust generation to pay higher taxes. On the other hand in the baby-bust generation fewer people will be competing for jobs and labor shortages may drive up wages. But they may find it hard to get promotions if upper-level positions are occupied by boomers.

What Are Some Effects of Population Decline?

Populations can decline afier replacement-level is reached if more people are in their postreproductive years (higher death rate than birth rates).

By 1996, 25 countries with 13% of the world's population had stable or declining populations. As the percentage of people age 65 or older increases between 1990 and 2150, more countries will begin experiencing population declines

Rapid population decline can lead to severe economic and social problems. A large proportion of older people consume a large share of medical. social security, and other costly public services. A country with a declining population can also face labor shortages increase automation or foreign workers.

Some European countries have offered economics incentives to encourage more births.

Case Study: The Graying of Japan

In seven years, between 1949 and 1956, Japan cut it's population growth in half, by access to family planning (from U.S. occupation forces). Since 1956 rates have declined further with the additional factors of: crainped housing, high land prices, late marriages and high costs of education. Japan's population should begin decreasing around 2006. But, Japan is beginning to face problems of an aging population: universal health insurance and pension funds used 42% of the national income in 1996, and this is projected to rise to 60% by 2020 (could hinder economic growth). Since 1980, the workforce has been declining, which is one reason Japan has invested in automation and encourages women to work outside the home. Japan is 99% Japanese and has been unwilling to increase immigration to provide workers. The country is becoming more dependent on illegal immigrants. Other countries will be watching to see how Japan makes the transition to zero population growth, and then to population decline.


A country can increase its population size through immigration, or decrease it through emigration. Canada, Australia and the United States are among the few countries that allow large increases in population from immigration.

Case Study: Immigration in the United States

In 1996, 40% of the U.S. population growth came from immigrants and refugees (935,000 legal and 400,000 illegal). Currently, 75% of all legal immigrants live in six states - California, Florida, Illinois, New York, New Jersey and Texas. Before 1960 most immigrants came from Europe; since then, most have come from Asia and Latin America. By 2050, half of the U.S. population will be Spanish speaking (up from 10% in 1993). Does immigration help or hinder the U.S. economy? Many economists say the answer is both. When unemployment is high, immigrants willing to work for lower wages can take jobs or lower wages of native-born workers. But they also take jobs many native-born workers do not want to do. According to a 1995 Cato Institute study, legal immigrants pay more in taxes in the long run than they used in public services, and they increase the supply of goods and generate wealth and jobs with their productive energies. States with high levels of immigration complain that the federal government gets most of the taxes while the states bear most of the costs. Some leaders want the federal government to crack down on illegal immigration, screen refugees better and reimburse states for all costs. Others want a constitutional amendment to deny citizenship to children of illegal immigrants to reduce the attractiveness of illegal immigration. In 1986 Congress passed a law prohibiting the hiring of illegal immigrants, and authorized funds to enforce the law, increase border staff by 50%, and to deport illegal immigrants. Most critics argue the law has not worked. Illegal immigrants can easily get fake documents and job histories. Some critics want a fingerprint-based ID card for all Americans to be able to detect illegal immigrants. The Immigration and Naturalization Service (INS) does not have enough money to patrol the U.S.- Mexico border. Many Mexican immigrants think being caught and sent back (often repeatedly) is a minor risk compared to remaining in poverty (60% unemployment or underemployment in Mexico). In 1995, the U.S. Commission on Immigration Reform recommended reducing legal immigration gradually to 700,000 and then to 550,000 a year. Some environmentalist want to limit it to 20% of annual growth (300,000-450,000). Most analysts also support reducing illegal immigration, but fear it will lead to discrimination against legal immigrants. Others argue that it would diminish the historical role of the U.S. as a place of opportunity for the poor and oppressed. Proponents argue limiting immigration.would help stabilize the population sooner which would help reduce the huge environmental impact of the United States.

What Are the Pros and Cons of Reducing Births?

Lowering the birth rate is the focus of efforts to slow population growth and 93% of the world's population live in countries with fertility reduction programs. The human population is projected to double between 1985 and 2050 from 5 to 10 billion. Can we provide enough food, water, energy, sanitation, housing? Can we provide basic necessities without using potentially renewable resources in an unsustainable way to survive? Can cities absorb billions more people and improve their standards of living without causing massive environmental damage? There is intense controversy concerning these questions. To some, the planet is already overpopulated, but others claim it could support 20-48 billion people at minimum survival level. Others believe the planet could support 7-12 billion at a decent standard of living by distributing land and food more equally. But could our social and political structures adapt to such a crowded world? Others say we should be asking what the optimum sustainable population of the earth is, based on the planet's cultural carrying capacily (Guest Essay). This optimum level would allow most people to live in reasonable comfort without preventing the earth to sustain itself for future generations. But, no one knows what this optimum level might be. Some people do not believe there is a risk of overpopulation. They believe that peo~e are the resource for solving the problems we face and the cause of poverty is the lack of free and productive economic systems. They argue that developed countries with declining populations will face shortages of workers, taxpayers, scientists and engineers, consumers and soldiers needed to maintain growth and power. They urge governments to give incentives to couples to have more children. Some people view population regulation as a violation of religious beliefs and an intrusion into their privacy and personal freedom. Developing countries and minorities may see it as a way to keep their numbers and power from rising. Proponents point out that we cannot provide the basic necessities for one out of five people on earth today, so how will we be able to do this for twice as many people. They also consider overpopulation as a threat to earth's life-support systems, which could by default raise death rates for humans. Adding millions and billions more people can only intensify many environmental and social problems.

Rapid population growth in developing countries is a major cause of unemployment. By 2025, l billion more people of working age will need jobs in developing countries; 33 million jobs per year for three decades will need to be created. Another argument for slowing population growth is that technological innovation, not numbers of people, is the key to militarv and economic power. Proponents believe developed countries should have an official goal of stabilizing their populations as soon as possible. This will also give them more credibility to influence less developed countries.. They also believe people should have the freedom to produce as manv children as they want, as long as it does not reduce the quality of other people's lives. Limiting an individuals freedom to protect the freedom of others is the basis of most laws in modern societies.

How Can Computer Models Be Used to Evaluate Limits to Growth?

Systems dynamics computer modeling can mimic the behavior of complex systems and make projections about how variables interact. First, mathematical equations that represent the interactions of key variables are developed; then the equations are fed into the computer to project future system behavior and to test potential effects of policy decisions.

A model was developed to evaluate the global limits to human population gro~th and industrialization by examining five variables: population, pollution, use of nonrenewable resources, industrial output per capita, and food output per capita. The projections, published in 1972 in The Limits 10 (growth, indicated that the limits to physical growth would be reached within 100 years and result in economic and ecological collapse. But, policy changes could forestall such collapse. In 1992, the authors updated their work in Beyond the Limits: Confrontimg Global Collapse, Envisioning a Sustainable Future. We have already overshot some limits and could face global economic and environmental collapse in the 2lst century. In their model, the researchers could evaluate courses of action by asking what if questions, such as the following:

What if the world's population and industrial output continue to expand exponentially at 1990 rates with no major policy changes?

Projection: collapse within the next 100 years due to depletion of nonrenewable resources and environmental overload. Doubling the supply ofnonrenewable resources would delay collapse about 20 years (even if no more children were born beginning in 1995).

What if we can use technology to double nonrenewable resource supplies, pollution control effectiveness, crop and timber yields, soil erosion protection, and the efficiency of resource use within 20 years; make birth control methods available to everyone by 1995; and stability current per capita industrial output at 1990 levels?

Projection: avoids overshoot and collapse, and results in a fairly smooth transition to a sustainable future. Developers of the model emphasize that these projections (not predictions) should be used as guidelines. Critics consider them too simplistic and believe advances in technology can present collapse.

How Can Economic Development Help Reduce Births?

Demographic transition is a hypothesis of population change that states as countries become industrialized, first their death rates decline and then their birth rates. Transition takes place in four distinct stages:

  • preindustrial state - harsh living conditions lead to a high birth rate (due to high infant mortality) and a high death rate - little population growth.
  • transitional stage - industrialization begins, better living conditions lead to a lower death rate and births remain the same - population growth rises.
  • industrial stage - industrialization is widespread, birth rate declines to level of death rate due to access to birth control, lower infant mortality, jobs for women, higher costs of raising children - population growth slows.
  • postindustrial stage - shifts to sustainable forms of economic development, birth rate declines (reaching zero population growth) and eventually falls below the death rate - population size slowly decreases.
  • Only a few countries in western Europe have entered the last stage. In most developing countries, death rates have fallen more than birth rates (transitional stage). Some analysts fear the still-rapid population growth will outstrip economic growth and overwhelm life-support systems. This demographic trap is happening now, especially in Africa. Many developing countries do not have enough skilled workers to produce the high-tech products needed to compete in the global market. Many also lack the capital and resources needed. Economic assistance to LDC's has been decreasing since 1980.

    How Can Family Planning Help Reduce Births?

    Family planning provides clinical services and education on birth spacing, birth control, breast-feeding (Spotlight), and prenatal care. Some people oppose family planning programs, mostly on religious grounds.

    The proportion of married women using modern contraception has increased from 10% in the 1960s to 55% in 1996, which is credited with 40% of the drop in fertility rates. Family planning can reduce the needs for children 's social services and bring a decline in abortions.

    Family planning and prenatal care can help reduce the risk of childbearing. According to the World Health Organization, the lifetime risk of dying from pregnancy or childbirth is 1 in 20 in developing countries, compared to 1 in 10,000 in developed countries.

    The delivery of family-planning services is inadequate in many developing countries, especially in rural areas. An estimated 300 million women want to limit the number and spacing of their children, but lack access to services, which could prevent an estimated 5.8 million births a year and 130,000 abortions a day. Others also call for expanding services to include teenagers and sexually active and unmarried women.

    Some analysts also urge education for males about the importance of having fewer children and taking more possibility for raising them. Men remain fertile longer than women and methods of birth control for men need to be developed.

    Family planning could be provided to all about $17 billion a year-less than a week's of worldwide military expeditures- and would help reduce population by about 2.7 billion. However, in 1996 the U.S. Congress cut over- planning, yet half of the pregnancies are unintended and about half of those end in abortion.

    How Can Economic Rewards and Penalties Be Used to Reduce Births?

    About 20 countries offer small payments to people who agree to use contraceptives or to be sterilized. These countries also doctors family-planning workers for each sterilization they perform and IUD they insert.

    China (and others) penalize couples who have more than one or two children by raising their taxes. Couples who have more children may lose health care, food allotments, and job options. Economic penalties can have more effect on the poor, and punish children for their actions of their parents.

    Economic rewards work best is they encourage (rather than mandate), but once a country's population growth is out of contol it may be forced to used coercive methods to prevent mass starvations and hardships.

    How Can Empowering Women Births?

    Women tend to have fewer and healthier children when they have accesses to education and paying jobs outside the home.

    Women (half of the world's population) do almost most of the domestic work and child care, provide health care and also do more than half the work associated with growing food, gathering fuel food and hauling water. $11 trillion of unpaid work by each year is not included in the world's standard accounting ($23 trillion is the annual global economic output).

    Women work two-thirds of all hours, but receive opnly one-tenth of the world's income and own 0.01% of the world's property. Women in many poor countries often receive less health care and suffer more from the malnutrition than men. Literacy rates for women are half those of men, and girls are often taken out of school to help with family chores.

    Women are excluded from economic and political decision making. They hold only 14% of the world's managerial positions and occupy only 10% of parlimentary seats.

    Empowering women with full legal rights will not only slow population growth but also promotes human rights and freedom. However, seeking gender equality will require some major social changes that will be difficult to achieve in male-dominated societies.


    What Success Has India Had in Controlling Population Growth?

    India began the world's first national family-planning program in 1952. In 1952, India added 5 million people to its population; in 1996 it added 18 million. With 36% of its population under age 15 it is projected to reach 1.4 billion people by 2025 and possibly 1.9 billion before leveling off in the 22nd century. Its population is growing exponentially at about 1.9% a year.

    The average per capita in India is $310 a year, and unemployment is nearly 50%. india itself- sufficient in food production, but 40% of its people suffer from malnutrition. Life expectancy is only 59 yers and the infant mortality rates is 79 death per thousand births.

    With 16% of the world's people, India has just 2.3% of land resources and 1.7 of forests. Some 40% of its cropland is degraded and 70% of its water is seriously polluted and sanitation services are often inadequate.

    Results of the family-planning program have been disappointing. Familes still have an average of 3.4 children (down from 5.3 in 1970). Social and cultural norms favor large familes, including a strong preference for male children. Though 90% of Indian couples know birth control methods, only 36% use them.

    In 1976, Indira Gandhi's offered financial ineffiencies for voluntary sterilization, but used coercion to meet quotas in some rural areas. The program failed and it may contributed to gandhi's defeat in 1977.

    A new approach was taken in 1978; raising the age for marriage from 18 to 21 for men and from 15 to 18 for women. Efforts have also been increased for family-planning (60% contraception use and replacement-level fertility), and the government is considering job and housing incentives for couples who meet thse goals.

    What Success Has china Had in Controlling its Population Growth?

    China has the world's largest population; 1.22 billion (4.6 times the U.S.). Between 1972 and 1996, China dropped its crude birth rate, from 32 to 17 per thousand people and its total fertility rate from 5.7 to 1.8 children per woman. But, with a growth rate of 1.1% China's population is projected to reach 1.5 billion by 2025.

    China has established the most extensive, intrusive and strict population control program in the world. Couples ares trongly urged to postponed the age of marriage and have only one child. There is accesses to free sterilization contraceptives and abortion even in rural areas.

    Couples who pledge have only one child are given extra food, pensions, better housing, free medical care, and their child will be given free school, tuition, and preferential in employment.

    China is a dictatorship with a homogenous population and common written language. This has made it easier to educate people and implement programs.

    But most countries prefer to avoid coercion in implementing plans, which would be inconsistent with democratic values and human rights. other parts of China programs could be used, especially localizing the programs (easy to get).

    China's large population has enormous environmental impact. The rivers are polluted, air pollution causing health problems, soil erosion is serious and timber resources could be depleted by 2016.