Migration is the physical movement of people from one place to another; it may be over long distances, such as moving from one country to another, and can occur as individuals, family units, or large groups. When referring to international movement, migration is called immigration.

Some interesting patterns occur with migration. Most people that migrate travel only a short distance from their original destination and usually within their country, often 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. Some people can voluntarily migrate based on individual choice. At other times, an individual must leave against his or her will. This is forced migration. Ultimately, the distance people migrate 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 risking to take their families.

Migration is very dynamic around the world, with peaks in different regions at different times. As noted earlier, there are several reasons why people migrate, but where are people relocating to or from? 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.

There are several reasons why people migrate known as push and pull factors, and they occur on economic, cultural, or environmental lines. 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 purposes. 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 push factors usually involve slavery, political instability, ethnic cleansing, famine, and war. People who choose to flee or are forced to flee as a result of these problems are often 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 considering internally displaced persons (IDPs). Cultural pull factors could include people who want to live in democratic societies, gender equality, or educational or religious opportunities.

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. This phenomenon is also known as transnational migration. 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. 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.

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 Hawaii 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/pull factors, such as droughts, also influence migration patterns. A very recent example of this is the drought and famine in East Africa. As anthropogenic climate change becomes more pressing, and hundreds of millions of people become displaced, the world will see more climate migrants forced from their homes.

The United States Agency for International Development (US AID) and the Famine Early Warning System Network 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 ecological 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, and membership of a particular social group or political opinion, who is outside the country of his nationality and, 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 large storm systems, water shortages, and more.

Questions for the Future

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 people on the planet, but they are not evenly distributed around the world. One consistent global pattern is water; nearly 80 percent of the world’s population lives near a large body of water.

• Why do you think populations converge on large bodies of water?
• What happens to populations when there is a shortage of water?

There are a variety of ways that geographers and demographers study population dynamics and profiles, often 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 is with the Demographic Transition Model. The model attempts to explain how more developed countries progressed with their demographics compared to less developed countries today. 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 of environmental and cultural factors.

Another area of debate is what the potential ramifications could be as the human population exceeds more than 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 less developed countries as a way to improve development.

Geographers also understand that humans are migrating species, and with technology, today can move across great distances. The reason for migration varies, but it all comes down to push or pull factors related to economic, political, social, or environmental reasons. 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. One thing we do know about human migration is that the majority of humans will die in the same town they were born in.