Chapter 4 | Population Growth and Decline

4.1 Why Populations Grow and Decline

Trends in Population

• Earth population grew slowly for a long time but exploded in the past 200 years.

Rate of natural increase (RNI): Rate at which a population grows as the result of the difference between the crude birth rate and the crude death rate

• This can indicate the rate of population growth but doesn’t take migration into account.
• RNI does, however, render an accurate picture of trends.

Doubling time (DT): The number of years in which a population growing at a certain rate would double, assuming the RNI stays constant.

• Looking at doubling time can be a useful way to compare trends among countries or regions, but doubling times can change from year to year.

• As a country’s RNI changes, its estimated population doubling time must also be recalculated.

• The (relatively) recent increase in human population growth was caused by a number of reasons. Most notably: the Industrial Revolution - major technological innovations, affected where people lived and worked

  • At the same time, there was agricultural progress.
  • People could grow more food with less labor and often on less land

• In addition, scientific discoveries contributed to new and better medicines, and sanitation practices began to improve.

  • This all contributes to lower rates of disease and infant mortality and improves the overall health of populations.

• The world’s population is not increasing at the same rate in all areas.

  • Countries in the periphery are seeing the highest rates of natural increase.

• Rapid population growth can challenge a country to meet its people’s needs for food, housing, medicine, schools, jobs, and other services.

  • Experts worry that the most rapid population growth is taking place in areas that may be least equipped to support larger numbers of people.

• Most countries in Europe have a negative RNI, meaning that the population in those places is declining or will soon begin to decline.

• The changes initiated during the Industrial Revolution had a powerful and unequal effect on the size of the population and its distribution and density.

• As a result of new technologies, jobs in many home-based industries moved into factories, which were largely located in cities.

  • The result was a mass migration from farms to cities, where people could find work and where population densities were higher than in rural areas.

Urbanization: Urban growth and development

• Countries in the periphery, with lower rates of industrialization, have generally remained more rural.
  • Presently, however, many peripheral countries are experiencing rapid urban growth as populations move from rural areas to cities.

Past, Present, and Future

• Changes because of industrialization and improvements in health and sanitation have contributed to rapid population growth.
  • Projections by the United Nations and others indicate that the world population will be nearly 10 billion by 2050.
• Some think that the world will buckle under the pressure of so many people and we may face great disasters like mass starvation, others believe the population will level out at a sustainable amount.
  • Differences in how we perceive the future depend in part on how we interpret and analyze the data.
  • Varying scenarios can be used for forecasting population growth and total population.

Factors that Influence Population Growth and Decline

• Changes in population in a given place or region are driven by the balance among three factors: mortality, fertility, and migration.
• These are influenced by the interplay of economic, political, environmental, and cultural factors, which vary from region to region and even from place to place.

Economic Factors

• The strength of a country or region’s economy can have a significant impact on both fertility and mortality.
• Birth rates tend to decline in times of economic hardship, particularly if people are concerned about having sufficient resources to support their children.
  • Conversely, birth rates often rise during more prosperous times.
• Access to health care, a key factor in fertility and mortality, can also be largely dependent on the economy.
  • In general, wealthier countries can provide better access to health care and necessary resources.
  • Good pre- and post-natal care also aid women in their time carrying babies.
• Types of economic activity also influence families’ decisions about childbearing, and thus fertility rates.
  • Families tend to be larger in agriculturally based economies, where children are often used for labor.
  • In industrial and post-industrial economies children may be viewed as an economic burden, leading to a lower crude birth rate.

Political Factors

• War, peace, and government policy play an important role in population trends.
• Countries can have pro- or anti-natalist policies, depending on if they aim to encourage or discourage higher birth rates respectively.
• War contributes to population decline in ways both obvious and more subtle.
  • As well as a higher mortality rate because of combat-related deaths and civilian casualties, war often results in food shortages or mass migration away from the conflict.
  • Just as people tend to have fewer children in times of economic hardship, they also hesitate to start families in times of conflict.
  • After the conflict has ended, there is often a spike in population as soldiers come home and people are more willing to start families.

Environmental Factors

• Natural disasters are just one environmental factor that can radically affect a region’s population.
• Famine and the spread of deadly diseases can also impact a population greatly.
  • Famine is often caused by drought, a natural disaster, or by political factors such as war.
  • It may affect a population not only through deaths by starvation but also by lowering fertility rates due to poor maternal health.
• Environmental factors also affect population distribution within regions and worldwide by encouraging migration.

Cultural Factors

• Cultural expectations play an important role in fertility rates.
• In societies where women tend to marry at a relatively young age and large families are the norm, the birthrate can be expected to be higher.
  • Similarly, in cultures were women are expected to wait longer to marry and have children, the birthrate is typically lower.
• Religion also has historically played an important role in a family’s decision to have children. Some religions are known to essentially require women to have children. Others actively teach against using contraception.
• Family planning (availability and access to contraceptive options) also has an impact on birth rates.
• Societies that discourage the use of contraception, often due to religious beliefs, tend to have higher birth rates than those that do not.
• Another factor that may influence population growth is education, particularly as it relates to medicine, prenatal care, health care, and nutrition.
  • More information results in fewer infant deaths (a lower IMR), a lower CDR, and greater life expectancy.
• While these factors might tend to increase population, this effect may be balanced by better education about contraception, which may result in a lower TFR.

The Changing Role of Women

• Changing social, economic, and political roles for women have influenced patterns of fertility.
• In many core countries, women in previous generations tended to stay home and raise children upon marriage.
  • Today in those countries, women are more likely to remain in the workplace and balance home- and work-life.
  • Professional women are postponing having children until after they have established their careers.
  • Some women may choose not to have a family at all—or to have fewer children.
• Combined with the availability of effective birth control options, the improved status and decision-making power of women contributes to a lower birth rate.
• In many cultures, however, strict gender division remains the norm.
  • In patriarchal societies, male babies are still preferred over female babies, girls receive less education, and women have few rights.
• Studies indicate that women who receive more schooling have a lower TFR, at least in part because they tend to marry later.
• In many countries women are discouraged from working outside the home, and cultural expectations call for them to care for all members of the family.
  • Evidence suggests that the chronic stress associated with caring for dependents contributes to poor health outcomes for caregivers.
• According to some recent evidence, increases in political power for women may also affect mortality.
  • Studies find that when more women are in legislative power, there was an estimated 9 to 12 percent decrease in maternal mortality rates.
  • Other studies find that it also correlates with lower infant mortality rates.

4.2 Theories of Population Change

Malthus’s Theory of Population Growth

• Thomas Malthus developed one of the earliest theories of population growth. He was a demographer who lived in England in the late 1700s-- The beginning of the Industrial Revolution.
  • He saw the way people were living longer and having more children live past infancy, and saw it as a sign that the world’s population would grow exponentially.
  • At the same time, he notices that food production was growing at a more constant rate.
• Malthus speculated that Britain’s accelerated population growth would contribute to a food shortage and famine by the late 1800s. This same idea could also be applied to the entire world.

Overpopulation: The condition in which population growth outstrips the resources needed to support life

• Malthus envisioned a bleak future in which only war, famine, and the spread of disease would check the excessive population growth.
• He believed it was critical for people to prevent the impending population explosion by lowering the birth rate.

Criticism of the Theory

• Malthus’ predictions were only accurate up to a point.
• What he did not foresee is that the RNI would eventually decrease, and people would not continue having the same amount of children they were previously.
• Nor did he predict contraceptives and the more recent technological advances that have increased agricultural output.
• More than 100 years later, Ester Boserup would challenge Malthus’ idea with the theory that a populations' size directly affects it’s food supply.
  • In other words, people would find ways to produce enough food to support a growing population.
• Another issue with Malthus’ theory is scale. His ideas may be accurate for certain regions where local agriculture is in no way able to sustain growing population.
  • But on a broader scale -- especially in a globally connected world where people don’t eat food that solely comes from their immediate area -- the principle does not apply as well.
• Some people accept only parts of Malthus’ ideas, but not the entire theory. They are called Neo-Malthusians.

Neo-Malthusian: Describing the theory related to the idea that population growth is unsustainable and that the future population cannot be supported by Earth's resources

• They raise concerns as to the sustainable use of the planet, and claim Earth can only support a finite amount of people.
• They, however, do not write off the possibility of slowing growth and avoiding the disaster Malthus predicted.

Demographic Transition Model

Demographic Transition Model: A model that represents shifts in the growth of the world’s populations, based on population trends related to birth rate and death rate

• Geographers use the DTM to better understand the relative stability of a population, and the factors that have contributed to population growth.

• Initially, the DTM depicted four stages in the development of a population, but demographers have recently added a fifth one.

• The first stage depicts the long period of human history before the improvements in health care and other changes at the time of the Industrial Revolution reduced the crude death rate.

• The population growth in Stage 2 corresponds with the continuing high birth rate and falling death rate that accompanies industrialization.

• Stages 3 and 4 reflect trends seen in societies as birth rates begin to slow due to a variety of economic and social factors.

• In Stage 5, population begins to decrease.

• According to the model, all regions, countries, and societies go through the first four stages, and they rarely return to an earlier stage.

  • In the present day, no country as a whole is in Stage 1, but some singular, isolated societies may be classified as such.
  • A few countries are thought to have reached Stage 5, such as Japan and Germany.

Evaluate the Model

• Although each stage seems distinct when observed on the chart, the divisions between them are not clear-cut.
  • The lines between one stage and the next can be fuzzy.
  • Regions and countries may progress through stages at different paces and time scales.
• It is important to note also that the DTM does not imply value judgments on societies.
  • A society classified as being in a later stage is not “better” than one in an earlier stage.
• The main criticism of the demographic transition model is that it is based solely on the experience of Western Europe (Where the DTM was developed) and may not be applicable to other parts of the world, particularly those that do not undergo the dramatic changes of rapid industrialization.
• Some feel that the DTM contributes to misleading interpretations of the data, implying causes and effects that may not exist.
  • Some experts argue that the DTM implies correlation = causation for certain factors that aren’t true everywhere.
  • For example, the DTM suggests that a rise in industry and technological advances affect the population, but others would argue the population change is responsible for the rise in industry; flipping the cause and effect.
• Geographers and demographers must probe more deeply to seek the underlying causes of population change at each stage.

Epidemiological Transition Model

Epidemiological transition model (ETM): A model that describes changes in fertility, mortality, life expectancy, and population age distribution, largely as the result of changes in causes of death

• The stages of the ETM do not correspond to the stages of the DTM; the ETM is an independent model incorporating cause-of-death patterns to explain population growth and decline.
• Epidemiological transition is the process by which a society goes from having high mortality rates (infant mortality, episodes of famine or disease) to having lower mortality rates (longer lifespans, deaths due to diseases that mainly affect the elderly.)
  • Prior to the 20th century, the transition was related to rising standards of living, nutrition, and sanitation.
• In the core countries, the transition is often fueled by advances in medicine and better access to health care.
• Stage one
  • High and fluctuating mortality rates
  • Low and variable life expectancy rates
  • Short periods of population growth that are not sustained
  • Populations are beginning to live closer together, increasing exposure to human/animal waste, contaminated water-- facilitates the rapid spread of disease
  • Attacks by animals and other humans
• Stage two
  • Increased average life expectancy from about 30 years to 50 years
  • The main causes of death are pandemics
  • As populations in urban areas grow, people are at risk from diseases like cholera, which is contracted from drinking contaminated water
  • Efforts to fight such diseases become more successful and the number of deaths due to pandemics is reduced
• Stage three
  • Main causes of death are chronic disorders associated with aging, including cardiovascular diseases and cancers
  • Because such diseases affect people at a relatively late stage of life, stage 3 is characterized by a longer life expectancy and lower death rate
• Stage four and five
  • More recent additions to the ETM model
  • Stage 4 reflects improvements in medicine that have extended life expectancy
  • New, more advanced methods for detecting cancer and cardiovascular diseases result in better patient outcomes
  • Some cancers are removed, and technological innovations such as new types of surgery and heart pacemakers address some cardiovascular disease.
  • Stage 5 sees a return of pandemic deaths
  • Between so many people living so close together and diseases becoming resistant to antibiotics, infectious disease is once again a large threat

Evaluate the Model

• The epidemiological transition model focuses only on health-related factors, and almost exclusively on disease.
• The ETM oversimplifies the causes and patterns of disease and mortality, which do not fit neatly into historical periods or geographic locations.
• The model fails to adequately distinguish the risk of dying from a specific/combined cause and makes assumptions about the impact of certain causes on overall mortality
  • The ETM overlooks the role that poverty plays in determining disease risk and mortality -- Poverty is a leading cause of shortened lifespans and may account for differences more than disease.
• The ETM does not address changes occurring in how people live.
  • There are new patterns in food consumption or other lifestyles that are not accounted for in the model
  • For example, people in core countries eat more processed food than ever, which may be linked to some diseases that the ETM attributes to longer lifespan
  • Incredibly frequent causes of death like car crashes are also not accounted for
• The causes of mortality may also be affected by human-caused environmental factors.
  • So could factors like food production, such as the pesticides used on crops.
  • Some diseases may be caused by construction trends, like how asbestos was a common building material before it’s cancer-causing quality was discovered.
• Global connectivity also changes how diseases spread.
  • According to the model, only certain stages would be affected by things like pandemics, but as seen with COVID-19, diseases are now capable of infecting the globe because of how much people and goods travel.

4.3 Population Policies

Types of Population Policies

• Government policies enacted to influence the natural rate of increase fall into two categories

Antinatalist: Describing attitudes or policies that discourage childbearing as a means of limiting population growth

Pronatalist: Describing attitudes or policies that encourage childbearing as a means of spurring population growth

Results and Consequences

• Pro- and anti-natalist policies have had mixed success.
  • Generally these policies only succeed if the population agrees with the governments policy on the need to increase/curb population growth.
• Pronatalist policies are harder to enforce. A country typically uses national pride and financial support to encourage people to have more children.
• Antinatalist policies can be easier to instate depending on how brutal the government is willing to be.
  • A more moral option is increasing access to contraceptives and family planning; financial incentives also work here. These policies tend not to work great either, however.
• There have been ethical concerns with antinatalist policies in the past.
• Sterilization on either sex can be a method of population control.
  • Sometimes, it is completely non-consensual.
  • Other times, poorer populations are targeted and are given payment for sterilization, which can appear as a choice, but for those deep in poverty may be the only option to create some income.
• Antinatalist countries are more common in African countries, who have some of the highest fertility rates in the modern day.
• Pronatalist policies are more common among European countries, some of which are experiencing a very low growth rate or an actual decrease in population.

4.4 Consequences of Demographic Change

Changed in Size and Composition

• The growth or decline of a population can have economic, cultural, and political effects.
• Economically…
  • Growing populations create greater demand for homes, goods, services
  • Prices increase as demand rises above supply
  • There may be insufficient housing stock, crowded schools, strained resources
  • Decreases in population free up housing and resources, prices go down, and generally have the opposite affect.
• Politically…
  • Governments must cope with the above mentioned needs such as need for housing and infrastructure/facilities
  • Governments may need to raise taxes to do this
• Population size affects the environment.
  • Rapid population growth can put groups at risk of exceeding the carrying capacity of their environment.

Land degradation: Long-term damage to the soil's ability to support life

• This can occur from over farming, deforestation, and human infrastructure damaging the area.

• Because of this, some researchers believe a decline in population would reflect positively on the Earth’s health and increase sustainability.

• Composition may be as important as size when examining a population’s social, economic, and political impacts.

  • Countries with imbalanced gender ratios face cultural and economic difficulties.

• The average age of a population and the relative number of people in different age brackets can have an impact on the economy.

  • An excessively large working-age population may make it difficult for people to find jobs and decrease wages.
  • A too-small working-age population means fewer people in the workplace, less economic output, and less money paid in income and other taxes.

• Government expenditures vary according to the age of the population as well.

  • A country with a relatively young population may need to build more schools for its children, while an aging population may need greater investment in facilities to care for the elderly.

Consequences of an Aging Population

• In many countries, particularly core countries, the dependency ratio is increasing due to the number of elderly people.
  • Projections predict that 16 percent of the world will be 65 and older by 2050.
• Aging populations are not equally spread across the world, and relate to what stage of the DTM any given country is in.
• Life expectancy has risen sharply for the entire world, and even more rapidly for certain regions.
  • This change, coupled with decreased fertility rates, is the main reason for the aging population in many countries.
• In general, people are living longer because they have better access to medical care, especially in core countries.
  • A better understanding about healthy lifestyle habits also contributes to longer lifespans.
• Although people living longer is a good thing, there are also challenges that come with it.
  • More elderly people mean more dependents who do not work and need care.
  • They also have no future of making more children, like a youth dependent.
  • This can be a huge drain on a population.
• Societies cannot avoid an aging population; they must adapt by confronting the challenges and taking advantage of the benefits this demographic change can bring about.

Social Effects

• Older populations can change family values.
  • In many cultures, multigenerational families are normal-- A wife was expected to move into the husbands home and care for his parents. This is changing, however, and less newly weds are opting for this living arrangement.
• Social changes like this one, coupled with demographic change, mean that fewer young people are available to care for aging parents at home.
  • Some countries have begun building many living facilities for the elderly, changing the social fabric of the culture.
• The social benefits of a larger elderly population cannot be overlooked.
  • Retired grandparents may be available to care for grandchildren, enabling both parents to return to work without the added cost of daycare.
  • When parents are unable to raise their children, often it is the grandparents who step in.
• Elderly people also play a key role in maintaining social networks that bind families and groups together and engage in community life.

Economic Effects

• The largest economic challenge of an aging population comes from the fact that retirees pay less in income taxes, which is a major revenue source for the government.
  • On average, retirees are living longer, adding to the costs of programs like social security, which are largely paid by taxes on younger people who are working.
  • As the cost of public retirement programs rises, taxes may also go up, or benefits for the retirees may be reduced.
• Living 20 or 30 years beyond retirement is no longer unusual, and some retirees run out of their personal savings long before the end of their lives.
  • Because people live longer, they often are ill or unable to fully care for themselves for a longer period of time. The cost of long-term care is very high and only increasing.
• The financial consequences of health care can span generations. When an aging parent requires round-the-clock care, an adult child may have to make economic sacrifices in order to care for that parent.
  • Some of these challenges are offset by economic benefits of an elderly population.
  • Older adults spend money on food, clothing, housing, and entertainment just as younger adults do, and they may stimulate growth in many economic sectors.
• Many jobs have been created in the healthcare sector to care for the elderly.

Political Effects

• Changes in the voting demographic may influence who is elected and what policies are enacted.
  • In some countries, elderly citizens have a strong voice in politics and are much more active voters.
• Political effects of an aging population are often intertwined with economic effects.
  • This can relate to policies that provide more relief to retirees, such as social security.
  • Elderly citizens are more likely to increase their own benefits despite the effects it has on the working population.
• Looser immigration policies can help alleviate the weight of elderly people on an economy by bringing in more working-age people.
  • Governments set immigration policies in response to a variety of economic and social pressures.