2 Population and Migration

Understanding how the human population is organized geographically helps us make sense of cultural patterns, the political organization of space, food production issues, economic development concerns, natural resource use and decisions, and urban systems. Additionally, themes of location, space, place, the scale of analysis, and pattern can be emphasized when studying fundamental population issues such as crude birth rates, crude death rates, total fertility rate, infant mortality rates, doubling time, and natural increase.

Explanations of why the population is growing or declining in some places are based on patterns and trends in fertility, demographic mortality, and migration. Analyses of refugee flows, immigration, and internal migration help us understand the connections between population phenomena. For example, environmental degradation and natural hazards may prompt population redistribution at various scales, which in turn creates new pressures on the environment, culture, and political institutions.

This chapter will analyze population trends across space and time as ways to consider models of population growth and decline, including Malthusian demographic transition, and the epidemiological (mortality) transition model.

essential understanding and Learning Objectives

Knowledge of the geographic patterns and characteristics of human populations facilitates an understanding of cultural, political, economic, and urban systems.

  • Analyze the distribution of human populations at different scales.
  • Use population density to explain the relationship between people and the environment.
  • Explain the implications of population distributions and densities.
  • Analyze population composition.

Populations grow and decline over time and space.

  • Explain contemporary and historical trends in population growth and decline.
  • Interpret and apply theories of population growth and decline.
  • Evalaute various national and internaional population policies.
  • Analyze reasons for changes in fertility rates in different parts of the world.
  • Explain the causes and implications of an aging population.

Causes and consequences of migration are influenced by cultural, demographic, economic, environmental, and political factors.

  • Explain how push and pull factors contribute to migration.
  • Apply the concepts of forced and voluntary migration to historical and contemporary examples.
  • Analyze major historical migrations.
  • Analyze the cultural, economic, environmental, and political consequences of migration.

2.1: Where Humans Live

Humans only occupy five percent of the Earth’s surface because oceans, deserts, rainforests, and glaciers cover much of the planet. The term for areas where humans permanently settle is called ecumene. Population growth and technology dramatically increase the ecumene of humans, which affects the earth’s surface and natural systems.

Issues and concerns of growing human populations have less to do with space and more to do with habitual locations and access to natural resources. All 7.5 billion people on the planet could live within an area the size of Los Angeles, California, but that is not desirable, sanitary, or sustainable. The reality is that humans cannot live in many parts of the world due to moisture, temperature, mountains, or growing season issues. Twenty percent of the world is too dry to support humans. This mostly has to do with large-scale high-pressure systems around 30 degrees north and south of the equator where constant sunny conditions have created some of the world’s largest deserts. Some of these include the Sahara, Arabian Peninsula, Thar, Takla Makan, and Gobi deserts. Most deserts do not provide enough moisture to support agriculture for large populations. Those who do live in these regions tend to raise animals and are considered nomads.

Regions that receive too much moisture also cause problems for human settlement. These are tropical rainforest regions located between the Tropic of Cancer (23.5 degrees North) and the Tropic of Capricorn (23.5 degrees South). The problem with these regions of the world has to do with the soil erosion due to high precipitation. High levels of precipitation greatly hinder agricultural production because nutrients in the soil are quickly washed away. This is partly why slash-and-burn agriculture occurs in these regions. Locals will burn part of the forest to put nutrients back into the ground. This only works for a short period because the precipitation washes away nutrients within a few years, so farmers move on to other parts of the forest with their slash-and-burn practices.

Additionally, regions that are too cold pose problems for large population clusters and food production. The cold polar regions have a short growing season, snow cover, permanently frozen land called permafrost, or high-pressure systems near the poles that limit the amount of moisture an area receives. Thus, cold polar regions are not only limited by temperature, but they are also limited by lack of moisture despite access to snow, ice, and glaciers. Mountainous and highland regions lack population clusters for similar reasons: steep slopes, snow and ice cover, and short growing seasons.

Because of these environmental factors, two-thirds of the world’s population is clustered into four geographic regions: Europe, East Asia, South Asia, and Southeast Asia. In Europe, three-fourths of people living there live in cities. In East Asia, most of the people live near coastal regions by the Pacific Ocean or near major river systems. Over half of the people in East Asia live in rural areas and are likely to be farmers. Similar to East Asia, people living in South Asia live near major river systems such as the Ganges and Indus rivers in order to have access to water for farming. Southeast Asia is quite different from the other three regions because most of the people live on islands within the Pacific and Indian oceans. But similar to East Asia and South Asia, the majority of people living in Southeast Asia live in rural areas and are likely to be farmers.

2.2: Global Population Trends

Arithmetic Density Map
Arithmetic Density Map

Agricultural density refers to the number of farmers valuable to arable land. A high agricultural density suggests that the available agricultural land used for farming and the farmers who are capable of producing and harvesting food is reaching its limit for that region. If the demand for food continues or rises, the risk is that there will not be enough arable land to feed their people. In contrast, an area with a low agricultural density has a higher potential for agricultural production. Economically, a low agricultural density would be favorable for future growth. Developed countries tend to have a much lower agricultural density because of technology. When geographers study and compare physiological and agricultural densities, they can analyze and determine the relationship between a country’s population and resources.


Population pyramid of China in 2016.
Population pyramid of China 2016.

A useful and critical tool used by scientists that focus on demographics, this included geographers, demographers, and social scientists, is a population profile called a population pyramid. A population pyramid visually demonstrates a particular region’s demographic structure about males and females and is often expressed in numbers or percentages. The following are some characteristics of population profiles:

  • A bell-shaped graph will indicate that a country has experienced high population growth in the early past but is experiencing a slow decrease.
  • Pyramids with a large base indicate countries with high population growth.
  • As a country’s population boom begins to age, a strange profile shape can develop with a wider top and a narrower base.
  • Populations that have stabilized have profiles where the majority of the pyramid is uniform in shape and gets smaller towards the top.
  • When a country has a large immigrant population, specifically “guest workers” than usually tend to be men, the male side of the graph will be dramatically wider than the women side of the graph.

If a country has experienced war, a catastrophic disaster, or a genocide that eliminates an entire generation, that generation will have a smaller number or percent than the generations before or after. For example, a major war may cause a reduction in populations in their mid-20s and 30s, and potentially a greater loss of males, which would appear on the profile graph.

Demographic Transition Model (DTM) pyramids.
Demographic Transition Model (DTM) pyramids.



Before we look at the model used to analyze how populations change, it is essential to look at key factors that influence the structure of a population. A region’s population will grow as long as their crude birth rates are greater than their crude death rates. A crude birth rate (CBR) is the total number of live births for every 1,000 people in a given year. So a crude birth rate of 10 would mean ten babies are born every year for every 1,000 people in that region. Crude death rates (CDR) are the total number of deaths per 1,000 people in a given year.

Crude Death Rates Map
Crude Death Rates Map

When CBRs are compared to CDRs, a region’s natural increase rate can be determined. A natural increase rate (NIR) is the percent a population will grow per year, excluding annual migration. Usually, a NIR of 2.1 is required to maintain or stabilize a region’s population. Any more than that and the population will grow, any less than a NIR of 2.1 causes population contraction. The reason why the NIR percent is 2.1 and not 2.0 for stability is because not every human will pair up and have a child because of genetics, choice, or death before childbearing years. Once we know the NIR, we can determine doubling time. Doubling time is the how many years would it take for a defined population to double in size, assuming that NIR stays the same over time. Over 95 percent of the world’s natural increase is occurring in developing countries. Subsaharan Africa and parts of Southwest Asia have NIR over 2.0, leading to large population growth, whereas regions in Europe have NIR near zero causing the population to decline. Currently, about 75 million people are added to the world’s global population every year.

The total fertility rate (TFR) is the average number of children a woman would be expected to have during the childbearing years (between 15-49 years old). The global average for TFRs is about 2.5, but in developing countries, it is as high as 5.0 or higher, and in more developed countries it is as low as 2.0 or less. The total fertility rate is a direct expression of a nation’s health care system because it reflects a population’s access to doctors, nurses, hospitals, and medicine.

The next important term to understand is the infant mortality rate (IMR). The IMR is determined by calculating how many children die before the age of 1 per 1,000 live births annually. The highest IMRs are in developing countries where rates can be as high as 80 or more. Conversely, in regions like Europe, it is as low as 5 per 1,000 live births annually.

Life expectancy at birth is an average of how many years a newborn is expected to live, assuming that mortality rates stay consistent. In more developed countries, the average life expectancy is over 80 years old, and in developing countries, it is only around 40 years. When we compare CBRs, CDRs, and TFRs, we find that the world has a large population of youth with the largest percent in developing countries. This causes high stress on the education systems and to some extent the health care systems within more impoverished countries.

However, more developed countries tend to have older demographics, which tends to cause stresses on the health care and social safety nets of those countries. The dependency ratio discussed later in this chapter, is used to understand these stresses and is the number of people who are too young or too old to work compared to the number of people who are in their “productive years.” The larger the ratio, the higher the economic stress on those nations.

2.4: Demographic Transition Model

Human geographers have determined that all nations go through a four-stage process called the Demographic Transition Model (DTM). The DTM’s function is to demonstrate the natural sequence of population change over time-based on development and modernization. This can help geographers, and other scientists examine the causes and consequences of fertility, mortality, and natural increase rates. Though controversial, the DTM has been used as the benchmark for forecasting human population growth regionally and globally.


Humans have lived in the first stage of the DTM for most of our existence. In this first stage, CBRs and CDRs fluctuated greatly regionally, globally, and over time because of living conditions, food output, environmental conditions, war, and disease. Ultimately, the natural increase of the world was stable because CBRs and CDRs were about equal. However, around 8,000 BC, the world’s population began to grow dramatically due to the agricultural revolution. During this time, humans learn to domesticate plants and animals for personal use and became less reliant on hunting and gathering for sustenance. This allowed for more stable food production and allowed village populations to grow. War and disease prevented population growth from occurring on a global scale.


Around the mid-1700s, global populations began to grow ten times faster than in the past because of the Industrial Revolution. The Industrial Revolution brought with it a variety of technological improvements in agricultural production and food supply. Increased wealth in Europe, and later North America, because the Industrial Revolution meant that more money and resources could be devoted to medicine, medical technology, water sanitation, and personal hygiene. Sewer systems were installed in cities; thus public health improved. All of this dramatically caused CDRs to drop around the world. At first, CBRs stayed high as CDRs dropped, this caused populations to increase in Europe and North America. Over time, this would change.

Africa, Asia, and Latin America moved into Stage 2 of the demographic transition model 200 years later for different reasons than their European and North American counterparts. The medicine created in Europe and North America was brought into these developing nations creating what is now called the medical revolution. This revolution or diffusion of medicine to this region caused death rates to drop quickly. While the medical revolution reduced death rates, it did not bring with it the wealth and improved living conditions, and development that the Industrial Revolution created. Global population growth is most significant in the regions that are still in Stage 2.


Today, Europe and North America have moved to Stage 3 of the demographic transition model. A nation moves from Stage 2 to Stage 3 when CBRs begin to drop while CDRs remain low or even continue to fall. It should be noted that the natural rate of increase in nations within Stage 3 is moderate because CBRs are somewhat higher than CDRs. The United States, Canada, and nations in Europe entered this stage in the early 20th Century. Latin American nations entered this stage later in the century.

Advances in technology and medicine cause decrease in IMR and overall CDR during Stage 2. Social and economic changes bring about a decrease in CBR during Stage 3. Countries that begin to acquire wealth tend to have fewer children as they move away from rural-based development structures toward urban-based structures because more children survive childhood and the need for large families for agricultural work decreases. Additionally, women gained more legal rights and chose to enter the workforce, own property, and have fewer children as nations move into Stage 3.


A country enters Stage 4 of the demographic transition model when CBRs equal to or become less than CDRs. When CBRs are equal to CDRs, a nation will experience zero population growth (ZPG). This occurs in many countries where girls do not live as long before they reach their childbearing years due to gender inequality.

A country in the first two stages of the transition model will have a broad base of young people and a smaller proportion of older people. A country in Stage 4 will have a much smaller base of young people (fewer children), but a much larger population of elderly (decreased CDR). A country with a large youth population is more likely to be rural with high birthrates and possibly high death rates; helping geographers analyze a nation’s health care system. Moreover, a country in Stage 4 with a large elderly population will have much fewer young people supporting the economy. These two examples represent the dependency ratio, mentioned earlier in this chapter. This ratio is the number of people, young and old, who are dependent on the working force.

Human geographers like to focus on the following demographic groups: 0-14 years old, 15-64 years old, and 65 and older. Individuals who are 0-14 and over 65 are considered dependents (though this is changing in older generations). One-third of all young people live in developing nations. Moreover, this places great strain on those nations’ infrastructure such as schools, hospitals, and day-care. Older individuals in more developed nations (MDL) benefit from health care services, but require more help and resources from the government and economy.

Another ratio geographers look at is the number of males compared to females, called the sex ratio.  Globally, more males are born than females, but males have a higher death rate than females.  However, understanding a country’s sex ratio and their dependency ratio helps human geographers analyze fertility rates and natural increase.

As noted earlier, population growth has increased dramatically in the last century. No country is still in Stage 1, and very few have moved into Stage 4. The majority of the world is either in Stage 2 or 3, which both have higher CBRs than CDRs; creating a human population over 7.5 billion today.


Many demographers believe a new stage in the DTM should be added to address issues starting to develop in countries within Europe and Japan. In this final stage, CBR would be extremely low and an increasing CDR. This would cause the area’s NIR to potentially become negative, leading to declining population growth. This may create an enormous strain on the social safety net programs of a country as is tries to support older citizens who are no longer working and contributing to the economy.

Currently, most of Europe has entered Stage 4. The United States would be approaching this stage if it were not for migration into the country. The first country that would enter Stage 5 would be Japan.

In summary, the demographic transition model is a model that helps human geographers understand and predict the demographics of individual nations. In Stage 1, CBR and CDR are very high and thus produce a low natural increase. In Stage 2, a nation’s CBR stays relatively high, but the CDR drops dramatically, producing the highest growth in population. In Stage 3, CDR stays low; however, changes in social customs and economic conditions. Finally, nations in Stage 4 have nearly equal CBR and CDR (sometimes higher CDR), creating a drop in natural increase.

2.5: Overpopulation

Overpopulation occurs when the number of people in an area exceeds the carrying capacity of the environment to support life at a decent standard of living. In 1798, Thomas Malthus published a short but revolutionary work called “An Essay on the Principle of Population.” Malthus states that two facts and one opinion would determine future population growth. The facts were that food is necessary for survival and that men and women would continue to have sex, thus producing offspring. His opinion is that if the population is not restrained by war, famine, and disease, population growth will occur exponentially. An example of exponential growth is 2, 4, 8, 16, 32, 64, 128, 256, 512, 1024 and so on. He also argues that agricultural production of food could only grow arithmetically. An example of arithmetic growth is 1, 2, 3, 4, 5, 6, 7 and so on. The overall assumption is that population growth will quickly grow beyond food production leading to food shortages and famines.

Malthus’ theory has not come to fruition due to technological advances in agriculture: fertilizers, insect and drought resistance, and better farming techniques. Some discredit Malthus because his hypothesis is based on the world supply of resources being fixed rather than expanding. Humans can expand the supply of food and other resources by using new technologies to offset the arable land limitations. Thus, we can use resources more efficiently and substitute new resources with scarce ones. Even with a global human population of 7 billion, food production has grown faster than the global rate of increase (NIR). Better growing techniques, higher-yielding, and genetically modified seeds, as well as cultivation of more land, have helped expand food supplies.

While new technologies have helped to increase food production, there are not enough emerging technologies to handle supply and demand. Adding to the problem is the fact that many insects have developed a resistance to pesticides. These problems have caused a slowdown and leveling off of food production in many regions of the world. Without breakthroughs in safe and sustainable food production, food supply will not keep up with population growth.

Others believe that population growth is not a bad thing. A large population could stimulate economic growth, and therefore, production of food. Population growth could generate more customers and more ideas for improving technology. Additionally, some maintain that no cause-and-effect relationship exists between population growth and economic development. They argue that poverty, hunger, and other social welfare problems associated with a lack of economic development, famines, and war are a result of unjust social and economic institutions, not population growth.

Recently there has been a rise in neo-Malthusians. One notable figure is Paul Ehrlich. In his very popular book, The Population Bomb, Ehrlich argues that population growth cannot continue without controls because the planet will reach the carrying capacity of our species. In short, we must consider environmental factors as we discuss overpopulation concerns. For example, even though humans produce four times the amount of food that we consume, we produce our food at the price of the environment. The rapid population growth of the world has caused massive deforestation in the Boreal Forests and rainforests, increasing desertification that encroaches into arable land, over-fishing of the oceans, mass extinction of species, air and water pollution, and anthropogenic climate change. All of these things have economic and environmental costs that we must consider.


Governments and other entities can dramatically influence population change as a way to increase or decrease population growth in a particular country. For example, some countries take dramatic steps to reduce their population. China’s One-Child Policy dictated that each family (husband and wife) could legally have only one child. Families that followed this policy were often given more money by the government or better housing. If a family illegally had another child, the family would be fined heavily. Children born illegally cannot attend school and have a difficult time finding jobs, getting government licenses, or even getting married. Some have reported that the government would force abortions on families with more than one child. One of the significant consequences of this policy was a dramatic increase in abortions and infanticides, especially of females. Female infanticide is linked directly to a global cultural trend that privileges males over females—baby boys are desired, especially if the family is only allowed, one child. This specific focus on eliminating women is called gendercide. Half the Sky, written by Nicholas Kristof and Sheryl WuDunn, documents global gendercide and what is being done to combat this problem.

After the two great world wars, the United Nations Population Commission and the International Planned Parenthood Federation began to advocate for more global population control. Many groups who advocate for population control focus on:

  • Changing cultural attitudes that keep population rates high (or low)
  • Providing contraception to developing countries
  • Helping countries study population trends by improving census counts
  • Empowering women and emphasizing gender equality


It is believed that worldwide, over 60 percent of women between ages 15-49 use some form of contraception, though this varies regionally. In the United States, contraception use is at nearly 75 percent, whereas in Africa it is around 30 percent. The consensus today is that the focus on population planning should be on gender equality and improving the social status of women around the world. This is the focus of the International Conference on Population and Development.


Religious organizations are also concerned with population growth; however, they focus on contraception issues and not strictly population growth. Some religions and political entities find contraception use immoral, which has influenced some governments to make access to them and use of them illegal.

2.6: Epidemiological Transition

One problem with the Demographic Transition Model is that it poorly considers health threats to populations within each stage. The epidemiological transition addresses precise health threats to countries in demographic transition. Said another way, it focuses on specific causes of death within each stage of the DTM. Epidemiology is a branch of health science that analyzes the causes, distribution, and control of disease in a population. Researchers in epidemiology have a strong background in geography and spatial science.


Infectious diseases and parasites are the greater killers of humans on the planet. The greatest epidemic in human history was the Black Plague, which killed nearly a half of Europe’s population between 1347 and 1350. It is believed that 25 million people died in those three years.


A pandemic is an epidemic of infectious disease that has spread across a large region, affecting high proportions of the population. Diseases like cholera and malaria greatly impact countries in Stage 2 of the DTM because of overcrowding, contaminated water sources, and lack of a strong health care infrastructure.


The causes of death for countries in Stage 3 of the DTM tend to be more from chronic disorders related to age and less from infectious diseases. Rather than dying from cholera, malaria, AIDS, or Ebola, populations in Stage 3 die from cancer or cardiovascular diseases such as heart attacks. The reason why countries in Stage 2 die less from degenerative diseases is that their life expectancy is much shorter.


Though degenerative diseases still exist for countries in this stage, medical advances and technology prolong the life expectancy further than countries in the third stage. Delayed degenerative diseases are reduced further as society makes lifestyle changes in health regarding diet, tobacco and alcohol consumption, and exercise.

2.7: Global Migration

Migration, a form of relocation diffusion, is defined as the permeant movement of people to a new location. Emigration is a form of migration from a particular location. Immigration is the migration to a new location. The numerical difference between emigration and immigration is called net migration.

Though geography does not have a comprehensive theory on migration, nineteenth-century geographer, E. G. Ravenstein created a few migration laws that can help us understand migration. These rules focus on the distance people migrate, the reasons why they relocate, and the characteristics of migrants.


Most people that migrate travel only a short distance from their original destination and usually within their country, usually due to economic factors. This is called internal migration. Internal migration can be divided up even further into interregional migration (the permanent movement from one region of a country to another region) and intraregional migration (the permanent movement within a single region of a country). The other type of migration is called international migration, which is the movement from one country to another. Roughly 10 percent of the people in the world are international migrants, meaning they currently live in a country they were not born in.

Some people are allowed to voluntarily migrate based on individual choice. At other times, a people relocate against their will, called forced migration. Ultimately, the distance people migrate is depends on economic, gender, family status, and cultural factors. For example, long-distance migration tends to involve males looking for employment and traveling by themselves rather than risk taking their families.

Migration is very dynamic around the world with peaks in different regions at different times. There are several reasons why people migrate to someplace or from someplace. Migration transition is the change in migration patterns within a society caused by industrialization, population growth, and other social and economic changes that also produce the demographic transition. A critical factor in all forms of migration is mobility, the ability to move either permanently or temporarily. Most international migrants come from countries in Stage 2 of the Demographic Transition Model, whereas internal migrants tend to originate from countries in Stage 3 or 4 of demographic transition.

There has been a dramatic increase in immigration into the United States from Latin America, Africa, and the Middle East. Some from these regions migrate to the U.S. out of economic necessity. We hear quite a lot about guest workers in the United States. These are individuals who migrate temporarily to take up jobs in other countries. Others migrate to escape conflicts such as the civil wars in Somalia, Sudan, and Ethiopia. Genocides in Rwanda (1994) and more recently Darfur, Sudan have forced internal and international migration. The wars in Afghanistan and Iraq have also forced migration from these regions. Washington Post reporter Sudarsan Raghavan reported on February 4, 2007, that the U.N. High Commission for Refugees estimates that over 2 million Iraqis (nearly 8 percent of the pre-war population) have been forced to migrate to nearby nations of Jordan, Syria, and Lebanon.


There are several reasons why people migrate, and these are called push and pull factors, and they usually occur because of an area’s political, economic, cultural, or environmental conditions. Push factors are events and conditions that compel an individual to move from a location. Pull factors are conditions that influence migrants to move to a particular location. The number one reason why people migrate is for economic reasons. This is because people either get “pushed” away from where they live due to a lack of employment opportunities or pulled because somewhere else either offer more jobs/higher paying jobs.

Cultural and political push factors usually involve slavery, political instability, ethnic cleansing, famine, or war. People who choose to flee or are forced to flee as a result of these problems are often called refugees. The United States Committee for Refugees classifies a refugee as someone who has been forced from their homes and cannot return because of their religion, race, nationality, or political opinion. In 2010, the United Nations High Commission for Refugees estimated that there are over 44 million people worldwide that have been forcibly displaced. The number grows to another 27 million when internally displaced persons are factored in. An internally displaced person (IDP) is someone who has been forced to migrate, but has not migrated across an international border. Some migrants are considered asylum seekers, who are people that have migrated to another country in hopes of being recognized as a refugee. Political or cultural pull factors could include people who want to live in democratic societies, gender equality, or educational or religious opportunities.

A variety of environmental push and pull factors also influence migration patterns. Environmental pull factors can include people wanting to live in particular environments. For example, many older adults like to live in southwestern states in the United States because they prefer the recreational opportunities that are provided for retired individuals. Some people want to live where snow activities are available or near an ocean.

Push factors often are related to the frequency of natural disasters such as earthquakes, tsunamis, hurricanes, or flash floods that a region could experience. Climatic push and pull factors, such as droughts, also influence migration patterns. A very recent example of this is the famine in Somalia. The main reason for environmental refugees is because of water; either too much or not enough. Sometimes people who want or need to relocate find various intervening obstacles, which are environmental or cultural features of the landscape that hinders migration.

US AID and the Famine Early Warning System track potential famines globally so that relief organizations can have a heads up and be more proactive when events occur. People who have been pushed for environmental reasons are called environmentally displaced persons (also called environmental refugees). The problem with these refugees is that they are not protected or given the same rights under the 1951 Refugee Convention. Under the convention, a refugee is a person with: “well-founded fear of being persecuted for reasons of race, religion nationality, membership of a particular social group or political opinion, who is outside the country of his nationality and is unable o, owing to such fear, is unwilling to avail himself of the protection of that country.” However, more and more people are becoming environmental refugees because of climate change, droughts, flooding from massive storm systems, water shortages, and more.


As mentioned earlier, most people relocate for economic push or pull factors. The United States, Canada, and Europe are primary locations migrants seek to relocate to for economic reasons. A struggle that many countries try to address is determining if a migrant is seeking economic opportunities or refugees fleeing governmental persecution. This distinction is important because many developed countries, including the United States, treat those two categories differently. Migrants who seek economic opportunities are less likely to be allowed into a country unless they provide a specific skill set the economy needs. If they are allowed into a country, it usually is on a temporary basis. Whereas, refugees receive special priorities with being allowed into a country and are more often than not, allowed to stay permanently.

A common practice of migrants who find work in another country will send a portion of their wages to family members back home. When migrants transfer money back to their home of origin, it is called remittance.


Ravenstein theorized that males were more likely to migrate than females, the longer the distance to relocate. The idea is that men are more likely to find employment than women. For much of human history, this was actually the case. But in the 1990s, gender patterns regarding migration began to change. Now, more women migrate to the United States than males.

Ravenstein also believed that long-distance migration occurred more with young adults, rather than children and elderly. In the United States, over 40 percent of immigrants are young adults. Children make up roughly 16 percent, and elderly make up less than 5 percent of immigration into the United States.

There is a growing concern of unaccompanied minors, between 12 to 17 years old in age, migrating to the United States. The majority of them are males, coming from Honduras and El Salvador because of gang violence.

2.8: Unauthorized Immigration

The political border between the United States and Mexico is 1,951 miles long. Currently, the United States has built various barriers along roughly one-quarter of the border. Protection of the border consists of a variety of technologies and resources including steel fences, drones, check-points, and immigration officers.

As noted earlier, the United States would be nearly the end of Stage 3 in the Demographic Transition Model if it were not for immigration. The desire to migrate to the United States continues to grow, but many cannot enter the country legally. Those who enter the country illegally, without proper documentation, are called unauthorized immigrants. The main pull factor for migrants to enter illegally is for economic reasons.

The Pew Hispanic Center believes that as of 2013, roughly 11.3 million unauthorized immigrants currently live in the United States. The Center also determined that California and Texas have the fastest growing unauthorized immigrants. The majority of them originate from Mexico, followed by Latin America. Of the 11.3 million unauthorized immigrants, roughly 1 million are children.

Unauthorized immigrants have also given birth to roughly 4.5 million babies, which are legal U.S. citizens under current law. And finally, of the 11.3 million unauthorized immigrants, approximately 8 million are currently employed in the United States.

There are greater concerns in the United States and Europe regarding unauthorized immigration. In the United States, many Americans are growing concerned about border security. In December 2018 through January 2019, the U.S. federal government was shut down over a dispute between Congress and the President around funding the government and border security. Most Americans want stronger border security, but question how much to pay and what to invest in for that protection. Others have concerns about jobs being given to unauthorized immigrants, even though most of those jobs are not sought after by most Americans.

Interestingly enough, unauthorized immigration is controversial in Mexico as well. Most of the immigration from Mexico comes from the north of the country. But immigration from Mexico’s southern border comes from Latin American countries such as Guatemala. The people of southern Mexico are unsure of immigration from their southern border for many of the same reasons as the United States.

In Europe, immigrants come from poorer regions from the south looking for economic opportunities. Poorer countries favor allowing their citizens to migrate to Europe as a way to take stress off their low employment. Immigrants who migrate to Europe also send remittances back to their places of origin. As a way to accommodate and benefit from these migrants, many European countries use to have guest worker programs. Typically, guest workers come from developing countries and are allowed to stay and work legally, temporarily. Circular migration occurs when a migrant temporarily moves to a country to work, returns home, but returns again when work is needed again. But today in Europe, most guest worker programs have been dissolved.

Attitudes of immigrants in Europe and the United States have eroded over the years. Many blame immigrants for crime, unemployment, and stress on their social safety net and welfare programs. Ultimately, anti-immigration groups fear that immigrants will interfere with cultural traditions as migrants bring different religions, languages, foods, and habits with them. These tensions are fueling extremist groups and a recent resurgence in nationalism, racism, and bigotry in Europe and the United States.


The United States created the Quota Act in 1921 and the National Origins Act in 1924, as a way to curb unrestricted immigration. These laws created a quota, a maximum limit on the number of people allowed to migrate to the United States every year. Because more migrants want to relocate to the United States than the country will allow in, the country has created the following priorities:

  • Roughly three-fourths of legal immigration into the United States is for family reunification.
  • Migrants who offer specific economic, scientific, or technological skill sets are the second largest group allowed to migrate into the country.
  • Finally, a small portion of migrants is allowed into the country through a lottery system to increase diversity from countries who have historically sent few people to the United States.

The quota system for the United States does not include refugees. Some countries have stated that because the United States allows migrants who offer important or skilled work to enter the country legally, it leads to a brain drain from the countries these migrants come from. Another aspect of immigration in the United States deals with chain migration. When skilled workers are allowed to migrate to the United States, they have the ability to bring family members into the country legally, called chain migration.


The issue of global human populations is often controversial because there is no clear consensus on how to deal with it. What demographers do know is that there are over 7.3 billion on the planet, but they are not evenly distributed evenly around the world. One global pattern that is consistent is water; nearly 80 percent of the world’s population lives near a large body of water.

There are a variety of ways that geographers and demographers study population dynamics and profiles, frequently representing this data in the form of diagrams, graphs, and most importantly maps. One-way social scientists have tried to describe historical, current, and future population trends are with the Demographic Transition Model. The model tries to describe how more developed countries progressed with their demographics through as compared to developing countries today. However, some argue that though the model predicts demographic trends in North America and Europe, the model does not accurately represent population trends in other regions of the world. Others say the model is too simplistic because environmental and cultural factors are not considered.

Another area of debate is what the potential ramifications could be as the human population exceeds past 8 and 9 billion by 2050. This debate started a while ago with the Malthus theory. Many ecologists believe humans have reached the earth’s carrying capacity and cannot sustain such large populations. Others argue that technology has consistently kept ahead of food scarcity concerns and that high populations could be a benefit for developing countries as a way to improve development.

Geographers also understand that humans are migrating species and with technology, today can move across vast distances. The reason for migration varies, but it all comes down to push or pull factors related to economic, political, social, or environmental reason. Many of these travelers are temporary living as guest workers until they need to move on. Today, many migrants are refugees, living in a variety of living conditions from complex metropolitans to squatter towns or refugee camps.


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Introduction to Human Geography by R. Adam Dastrup, MA, GISP is licensed under a Creative Commons Attribution 4.0 International License, except where otherwise noted.

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