Introduction to Sociology/Demography

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Contents 1 Introduction 2 Why study demography? 3 History 4 Data and Methods 4.1 Demographic Indicators 4.2 Fertility and Fecundity 4.3 Mortality 5 The Demographic Transition 6 Population Growth and Overpopulation 6.1 Early Projections of Overpopulation 6.2 Population as a function of food availability 6.3 The optimist's viewpoint on population growth 6.4 Effects of overpopulation 6.5 Possible Solutions to Overpopulation 7 References

[edit] Introduction

Demography is the study of human population dynamics. It encompasses the study of the size, structure and distribution of populations, and how populations change over time due to births, deaths, migration, and ageing. Demographic analysis can relate to whole societies or to smaller groups defined by criteria such as education, religion, or ethnicity.

[edit] Why study demography?

Before proposing complex theories to explain sociological phenomena (e.g., World Systems Theory), especially at the macro and/or societal levels, sociologists should first turn to demographic indicators for possible explanations. Demographic analysis is a powerful tool that can explain a number of sociological phenomena.

For instance, in examining the elements that led to the first World War, most people turn to political and diplomatic conflicts but fail to consider the implications of expanding populations in the European countries involved. Expanding populations will result in increased competition for resources (i.e., food, land, access to trade routes and ports, etc.). Expanding populations may not be the primary cause of World War I, but it may have played a role in the increased hostilities leading up to the war. In this fashion, demographic indicators are often informative in explaining world events and should be turned to first as explanations.

[edit] History

The study of human populations has its roots, like sociology generally, in the societal changes that accompanied both the scientific and industrial revolutions. Some early mathematicians developed primitive forms of life tables, which are tables of life expectancies, for life insurance and actuarial purposes. Censuses, another demographic tool, were institued for primarily political purposes:

• as a basis for taxation
• as a basis for political representation

The development of demographic calculations started in the 18th century. Census taking, on the other hand, has a long history dating back close to 2,000 years among the Chinese and the Romans and even further back in history among some groups in the Middle East. Most modern censuses began in the late 18th century.

[edit] Data and Methods

Demography relies on large data sets that are primarily derived from censuses and registration statistics (i.e., birth, death, marriage registrations). Large data sets over long periods of time (e.g., the U.S. census is conducted every 10 years) are required to develop trends in demographic indicators, like birth and death rates.

In many countries, particularly in developing nations, reliable demographic data are still difficult to obtain. In some locales this may be due to the association of census with taxation.

[edit] Demographic Indicators

Because demography is interested in changes in human populations, demographers focus on specific indicators of change. Two of the most important indicators are birth and death rates, which are also referred to as fertility (see also fecundity) and mortality. Additionally, demographers are interested in migration trends or the movement of people from one location to another. Some of the specific measures used to explore these elements of population change are discussed below.

[edit] Fertility and Fecundity

Fertility, in demography, refers to the ability of females to produce healthy offspring in abundance. Fecundity is the potential reproductive capacity of a female. Some of the more common demographic measures used in relation to fertility and/or fecundity include:

• crude birth rate: the annual number of live births per thousand people
• general fertility rate: the annual number of live births per 1000 women of childbearing age (often taken to be from 15 to 49 years old, but sometimes from 15 to 44).
• age-specific fertility rate: the annual number of live births per 1000 women in particular age groups (usually age 15-19, 20-24 etc.)
• total fertility rate: the number of live births per woman completing her reproductive life if her childbearing at each age reflected current age-specific fertility rates
• gross reproduction rate: the number of daughters who would be born to a woman completing her reproductive life at current age-specific fertility rates
• net reproduction rate: the number of daughters who would be born to a woman according to current age-specific fertility and mortality rates

Another important demographic concept relating to fertility is replacement level. Replacement level fertility refers to the number of children that a woman (or monogamous couple) must have in order to replace the existing population. Sub-replacement fertility is a fertility rate that is not high enough to replace an existing population. Replacement level fertility is generally set at 2.1 children in a woman's lifetime (this number varies by geographic region given different mortality rates). Sub-replacement fertility is below approximately 2.1 children in a woman's life time. The reason the number is set to 2.1 children per woman is because two children are needed to replace the parents and an additional one-tenth of a child is needed to make up for the mortality of children and women who do not reach the end of their reproductive years. Of course, women don't have one-tenth of a child; this results from statistical averaging between women who have more than two children and those who have two or fewer children.

The chart below illustrates trends in childbearing by region of the world. Fertility rates dropped earlier in the more developed regions of the world, followed by Asia and Latin America. Fertility rates are just starting to decline in Africa.

The chart below highlights the varied fertility rates of specific countries as some have very low fertility rates, many have moderate rates, and some have very high rates.

The following chart illustrates the relationship between contraceptive use and the total fertility rate by regions of the world. Increased contraceptive use is associated with lower numbers of children per woman.

One of the strongest predictors of fertility rates is women's educational attainment.^[1] Almost universally, higher levels of educational attainment result in lower fertility rates. It is not, however, education itself that causes declines in fertility but rather its association with other factors that reduce fertility: women with higher levels of education delay marriage, have improved labor market opportunities, are more likely to use contraception during intercourse, and are less likely to adopt traditional childbearing roles.^[1]

[edit] Mortality

Mortality refers to the finite nature of humanity: people die. Mortality in demography is interested in the number of deaths in a given time or place or the proportion of deaths in relation to a population. Some of the more common demographic measures of mortality include:

• crude death rate: the annual number of deaths per 1000 people
• infant mortality rate: the annual number of deaths of children less than 1 year old per thousand live births
• life expectancy: the number of years which an individual at a given age can expect to live at present mortality rates

Note that the crude death rate as defined above and applied to a whole population can give a misleading impression. For example, the number of deaths per 1000 people can be higher for developed nations than in less-developed countries, despite standards of health being better in developed countries. This is because developed countries have relatively more older people, who are more likely to die in a given year, so that the overall mortality rate can be higher even if the mortality rate at any given age is lower. A more complete picture of mortality is given by a life table which summarizes mortality separately at each age.

This chart depicts infant mortality by region of the world. The less developed regions of the world have higher infant mortality rates than the more developed regions.

This chart depicts life expectancy by region of the world. Similar to infant mortality, life expectancies are higher in more developed regions of the world.

According to recent research,^[2] one of the best predictors of longevity (i.e., a long life) is education, even when other factors are controlled: the more educated you are, the longer you can expect to live. A few additional years of schooling can add several additional years to your life and vastly improve your health in old age. The mechanism through which this works is not the schooling itself, but schooling's influence on other health-related behaviors. The more education someone has, the lower his/her likelihood of smoking and engaging in unhealthy and high risk behaviors. Education also increases the probability of people engaging in healthy behaviors, like frequently exercising.^[2]

Other factors associated with greater longevity include:

• wealth: money increases access to good healthcare, which improves health and increases longevity
• race: whites live longer than blacks, though this is due to other social disparities, like income and education, and not to race itself
• ability to delay gratification: with the ability to delay gratification people live healthier lives and engage in healthier behaviors (e.g., exercise)
• larger social networks: having a large group of friends and close relationships with relatives increases your social support, which positively influences health
• job satisfaction: people in more powerful and more satisfying jobs tend to be healthier than people in less satisfying jobs

[edit] The Demographic Transition

The demographic transition is a model and theory describing the transition from high birth rates and death rates to low birth and death rates that occurs as part of the economic development of a country. In pre-industrial societies, population growth is relatively slow because both birth and death rates are high. In most post-industrial societies, birth and death rates are both low. The transition from high rates to low rates is referred to as the demographic transition. This understanding of societal changes is based on the work of Thompson,^[3] Blacker,^[4] and Notestein,^[5] who derived the model based on changes in demographics over the preceding two hundred years or so.

The beginning of the demographic transition in a society is indicated when death rates drop without a corresponding fall in birth rates (usually the result of improved sanitation and advances in healthcare). Countries in the second stage of the demographic transition (see diagram) experience a large increase in population. This is depicted in the diagram when death rates fall in stage two but birth rates do not fall until stage three. The red line begins its rapid upward growth in stage two and begins to level off at the end of stage three.

By the end of stage three, birth rates drop to fall in line with the lower death rates. While there are several theories that attempt to explain why this occurs (e.g., Becker and Caldwell, who view children as economic commodities),^[6][7] why birth rates decline in post-industrial societies is still being evaluated. Many developed countries now have a population that is static or, in some cases, shrinking.

As with all models, this is an idealized, composite picture of population change in these countries. The model is a generalization that applies to these countries as a group and may not accurately describe all individual cases. Whether or not it will accurately depict changes in developing societies today remains to be seen. For more information on the demographic transition, see here.

[edit] Population Growth and Overpopulation

Overpopulation indicates a scenario in which the population of a living species exceeds the carrying capacity of its ecological niche. Overpopulation is not a function of the number or density of the individuals, but rather the number of individuals compared to the resources they need to survive. In other words, it is a ratio: population over resources. If a given environment has a population of 10, but there is food and drinking water enough for only 9 people, then that environment is overpopulated, while if the population is 100 individuals but there are food and water enough for 200, then it is not overpopulated.

Resources to be taken into account when estimating if an ecological niche is overpopulated include clean water, food, shelter, warmth, etc. In the case of human beings, there are others such as arable land and, for all but tribes with primitive lifestyles, lesser resources such as jobs, money, education, fuel, electricity, medicine, proper sewage and garbage management, and transportation.

Presently, every year the world's human population grows by approximately 80 million. About half the world lives in nations with sub-replacement fertility and population growth in those countries is due to immigration. The United Nations projects that the world human population will stabilize in 2075 at nine billion due to declining fertility rates source.

Today about half the world lives in nations with sub-replacement fertility. All the nations of East Asia, with the exceptions of Mongolia, the Philippines, and Laos are below replacement level. Russia and Eastern Europe are in most cases quite dramatically below replacement fertility. Western Europe also is below replacement. In the Middle East Iran, Tunisia, Algeria, Turkey, and Lebanon are below replacement. Canada, Australia, and New Zealand are similar to Western Europe, while the United States is just barely below replacement with about 2.0 births per woman. All four of these nations still have growing populations due to high rates of immigration.

[edit] Early Projections of Overpopulation

Early in the 19th century, Thomas Malthus argued in An Essay on the Principle of Population that, if left unrestricted, human populations would continue to grow until they would become too large to be supported by the food grown on available agricultural land. He proposed that, while resources tend to grow arithmetically, population grows exponentially. At that point, the population would be restrained through mass famine and starvation. Malthus argued for population control, through moral restraint, to avoid this happening.

The alternative to moral restraint, according to Malthus, is biological and natural population limitation. As the population exceeds the amount of available resources the population decreases through famine, disease, or war, since the lack of resources causes mortality to increase. This process keeps the population in check and ensures it does not exceed the amount of resources.

Over the two hundred years following Malthus's projections, famine has overtaken numerous individual regions. Proponents of this theory, Neo-Malthusians state that these famines were examples of Malthusian catastrophes. On a global scale, however, food production has grown faster than population. It has often been argued that future pressures on food production, combined with threats to other aspects of the earth's habitat such as global warming, make overpopulation a still more serious threat in the future.

[edit] Population as a function of food availability

Recent studies take issue with the idea that human populations are naturally explosive. Thinkers such as David Pimentel, Alan Thornhill, Russell Hopffenberg, and Daniel Quinn propose that, like other animals, human populations predictably grow and shrink according to their available food supply - populations grow when there is an abundance of food and shrink in times of scarcity.

Proponents of this theory indicate that every time food production is intensified to feed a growing population, the population responds by increasing even more. Some human populations throughout history support this theory, as consistent population growth began with the agricultural revolution, when food supplies consistently increased. This can be observed in cultural contexts, as populations of hunter-gatherers fluctuate in accordance with the amount of available food and are significantly smaller than populations of agriculturalists, who increase the amount of food available by putting more land under agriculture.

For some, the concept that human populations behave in the same way as do populations of bears and fish is troubling to believe; for others it indicates a feasible solution to population issues. In either case, since populations are tied to the food they consume, it seems that discussions of populations should not take place without considering the role played by food supply.

Critics of this idea point out that birth rates are voluntarily the lowest in developed nations, which also have the highest access to food. In fact, the population is decreasing in some countries with abundant food supply. Thus human populations do not always grow to match the available food supply. Critics cite other factors that contribute to declining birth rates in developed nations, including: increased access to contraception, later ages of marriage, the growing desire of many women in such settings to seek careers outside of childrearing and domestic work, and the decreased economic 'utility' of children in industrialized settings.^[6][7] The latter explanation stems from the fact that children perform a great deal of work in small-scale agricultural societies, and work less in industrial ones; this interpretation may seem callous, but it has been cited to explain the drop-off in birthrates worldwide in all industrializing regions.

Food production has outpaced population growth, meaning that there is now more food available per person than ever before in history. Studies project that food production can continue to increase until at least 2050. Using modern agricultural methods, the Food and Agriculture Organization of the U.S. has predicted that developing countries could sustain a population of 30 billion people source.

[edit] The optimist's viewpoint on population growth

Some studies have argued that the current population level of over six billion may be supported by current resources, or that the global population may grow to ten billion and still be within the Earth's carrying capacity. Buckminster Fuller and Barry Commoner are both proponents of the idea that human technology could keep up with population growth indefinitely. The assumptions that underlie these claims, however, have been strongly criticised. One criticism is that poor people can't afford such technologies.

[edit] Effects of overpopulation

In any case, many proponents of population control have averred that famine is far from being the only problem attendant to overpopulation. These critics point out ultimate shortages of energy sources and other natural resources, as well as the importance of serious communicable diseases in dense populations and war over scarce resources such as land area. A shortage of arable land (where food crops will grow) is also a problem.

The world's current agricultural production, if it were distributed evenly, would be sufficient to feed everyone living on the Earth today. However, many critics hold that, in the absence of other measures, simply feeding the world's population well would only make matters worse, natural growth will cause the population to grow to unsustainable levels, and will directly result in famines and deforestation and indirectly in pandemic disease and war.

Some of the other characteristics of overpopulation include:

• Child poverty
• High birth rates
• Lower life expectancies
• Lower levels of literacy
• Higher rates of unemployment, especially in urban
• Insufficient arable land
• Little surplus food
• Poor diet with ill health and diet-deficiency diseases (e.g. rickets)
• Low per capita GDP
• Increasingly unhygienic conditions
• Government is stretched economically
• Increased crime rates resulting from people stealing resources to survive
• Mass extinctions of plants and animals as habitat is used for farming and human settlements

Another point of view on population growth and how it effects the standard of living is that of Virginia Abernethy. In Population Politics she shows evidence that declining fertility following industrialization only holds true in nations where women enjoy a relatively high status. In strongly patriarchal nations, where women enjoy few rights, a higher standard of living tends to result in population growth. Abernathy argues that foreign aid to poor countries must include significant components designed to improve the education, human rights, political rights, political power, and economic status and power of women.

[edit] Possible Solutions to Overpopulation

Some approach overpopulation with a survival of the fittest, laissez-faire attitude, arguing that if the Earth's ecosystem becomes overtaxed, it will naturally regulate itself. In this mode of thought, disease or starvation are "natural" means of lessening population. Objections to this argument are:

1. in the meantime, a huge number of plant and animal species become extinct
2. this would result in terrible pollution in some areas that would be difficult to abate
3. it obviously creates certain moral problems, as this approach would result in great suffering in the people who die

Others argue that economic development is the best way to reduce population growth as economic development can spur demographic transitions that seem to naturally lead to reductions in fertility rates.

In either case, it is often held that the most productive approach is to provide a combination of help targeted towards population control and self-sufficiency. One of the most important measures proposed for this effort is the empowerment of women educationally, economically, politically, and in the family. The value of this philosophy has been substantially borne out in cases where great strides have been taken toward this goal. Where women's status has dramatically improved, there has generally been a drastic reduction in the birthrate to more sustainable levels. Other measures include effective family planning programs, local renewable energy systems, sustainable agriculture methods and supplies, reforestation, and measures to protect the local environment.

David Pimentel, a Cornell University professor of ecology and agricultural sciences, sees several possible scenarios for the 22nd century:

1. a planet with 2 billion people thriving in harmony with the environment
2. or, at the other extreme, 12 billion miserable humans suffering a difficult life with limited resources and widespread famine

Spreading awareness of the issues is an important first step in addressing it.

[edit] References

This chapter also draws on the following Wikipedia articles:

• migration
• demography
• demographic transition
• overpopulation

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