Human Migration: Patterns, Causes, and Global Population Trends

Posted on Dec 17, 2024 in Geography

Migration: Causes and Classifications

Migration is the movement of people who cross a political boundary with the intention of leaving their place of residence.

Causes of migration include political conflicts, war, and religious, social, and cultural issues. Natural disasters like earthquakes and floods, as well as environmental disasters such as desertification, also contribute. Technological advances in economic activities play a role.

There are many classifications of migration based on various criteria: the duration, the causes, the wishes of the migrant, the degree of skill, etc.

Classification Based on the Boundaries of Countries

  • Internal or domestic migration: Involves a change of residence within the country.
  • External or international migration: Refers to changes of residence between countries.

Classification of International Migration According to the United Nations

  • Permanent or long-term migration: People who enter a country to settle permanently.
  • Short-term labor migration: Includes temporary foreign labor aimed at filling jobs that require highly specialized expertise (professional).
  • Undocumented migration: International migrants who have not met the requirements set by the host country to enter its territory, reside, or engage in gainful employment within it.
  • Refugees and asylum seekers: Persons who flee their country due to a well-founded fear of persecution.

The Main Migration Flows

Migrant-sending countries are mainly concentrated in the less developed regions of the southern hemisphere. The population migrates to neighboring countries of the region or to the industrialized countries of Europe, Anglo-America, Australia, and Japan in search of jobs and a better quality of life.

  • In Asia and Africa, migration flows occur mainly within those continents. The oil-producing countries show the strongest proportion of immigrants.
  • In Africa, South Africa is a focal point for the countries located south of the Sahara. In North Africa, migration flows are directed towards Europe.
  • In America, Central America and the Caribbean are the main areas of population ejecting, moving to the United States. Argentina and Venezuela make up centers of attraction, especially for their neighbors.
  • Western Europe is another target area for international migrants.
  • Australia and New Zealand are also receiving countries of immigration.

Refugees in the World

Migration forms a kind of forced or involuntary migration status. Refugees are defined as “legal persons fleeing their country due to a well-founded fear of persecution for reasons of race, religion, nationality, membership of a particular social group, or political opinions.” The UNHCR (High Commissioner for Refugees) was established in 1950 with the aim to protect and provide lasting solutions to these people.

For UNHCR, there are three types of durable solutions for refugees:

  • Voluntary Repatriation: Return voluntarily to their country of origin.
  • Resettlement: Transfer of refugees to a third country other than the country of asylum.
  • Local Integration: Stay in the country that hosted them.

Human Development Index

The United Nations Program for Development (UNDP) created the Human Development Index (HDI) in 1990. This measures the overall progress of a country in three basic dimensions of human development. For each dimension, a variable has been chosen to represent it.

The HDI reduces all three basic indicators to a value that indicates how far the country has to move up to the maximum possible. This index ranges from 1 (best) to 0 (worst).

Countries are ranked by HDI into 3 groups:

  • Countries with high human development, with HDI values of 0.800 and above.
  • Countries with medium human development: values between 0.500 and 0.799.
  • Countries with low human development, with values less than 0.500.

Population Distribution

To analyze the distribution of the population, the concept of population density is used. Population density is the relationship between population size and the surface area; it is expressed in inhabitants/km2.

The unequal spatial distribution is the outcome of the interaction of different factors that have caused or exacerbated it.

Among the factors that explain the uneven distribution of population, include:

Physical Factors

  • Relief: Plains are the most suitable for the establishment of the population. This factor is also associated with latitude. At low latitudes (warm climates), the valleys and plateaus of average height offer great advantages due to the mild climate. At mid-latitudes (temperate), relief plains are more suitable for settlement.
  • Weather: Temperate climates are the most suitable for human life and economic activities.
  • Nature of soils: Its aptitude for farming.
  • Availability of potable water

Economic Factors

  • Presence of natural resources
  • Installation of industries
  • Ease of communication
  • Proximity to the sea

Historical and Political Factors

  • Process of occupation of territory
  • Policies of population and birth control
  • Incentives or restrictions on foreign entry

As a result of demographic concentration, we can distinguish:

  • Vacuum demographics or areas with very low densities (up to 1 per km2)
  • Areas with intermediate densities (1 to 50 per km2)
  • Large pockets of population concentration (more than 50 per km2)

The Population Structure

When we talk about the population structure of a society, we are referring to a comparison by age and sex. It is an indicator for projects in economic and social leadership, is used to measure labor supply in a country, and influences the split on the needs of goods and services.

For example, in a country dominated by youth, more resources should be provided for education, family support, etc.

In contrast, in those where the elderly population is higher, more resources should be allocated to pensions and health.

The structure of a population is the outcome of the interaction between “birth and death,” but other indicators such as fertility and life expectancy also come into play.

  • Birth rate: The number of births that occur in a population of 1000 people in one year.
  • Death rate: Expresses the number of deaths per 1000 inhabitants in one year.
  • Fertility: The average number of children per woman.
  • Life expectancy at birth or half-life: The age each person can theoretically aspire to at birth.
  • Infant mortality rate: The number of children from 0 to 1 year old who die per 1000 births.

To observe the structure of a population, as well as knowing how it evolved over time (if it increased, decreased, or remained stable), we also need to know about its composition by gender and age.

A population can be classified as:

  • Young.
  • Depending on the adult age group that predominates.
  • Aged.

The junior class is called passive transient (0 to 14).

Adults are active (15 to 64).

Aged or final passive (+65).

Young or elderly are considered inactive or passive, so they must be held by adults, i.e., the economically active population.

Despite these technical definitions, we know that many elderly people and children in the world must work to support themselves financially, and even contribute to the livelihood of the “economically active” people who may be affected by growing unemployment.

To better understand the population structure by age and sex, a “population pyramid” is made, which allows us to analyze the birth rate, fertility, and mortality over time. Also, events such as wars and epidemics.

One can distinguish 3 main pyramid profiles:

  • Pyramid regressive (urn).
  • Pyramid stationary (bell).
  • Pyramid or expansive progressive.

Empty Demographics

Represent more than a quarter of the land surface and are home to only 2% of humanity. These centers are located in sparsely populated arid lands and in the warm and humid.

  • Cold regions of both hemispheres and areas bounded by the line of eternal snow, also called white deserts, are the regions most hostile to human presence due to the short ice-free periods and low temperatures.
  • The biggest obstacle to the permanent occupation of the arid (yellow desert) is the scarcity of water and soils lacking organic matter, and the development of agriculture and animal husbandry are diminished. There are small concentrations of population in the oasis, around wells and water courses, associated with the exploitation of mineral or petroleum resources. There are also groups of nomadic herders. The most representative areas consist of the Sahara, Saudi Arabia, the deserts of the western United States, west-central Australia, the Puna de Atacama, etc.
  • Warm and humid areas (green deserts) are located around Ecuador, for example, the Amazon Basin in South America and the island of New Guinea in the Pacific Ocean. The high percentages of moisture, high temperatures, and abundance of vegetation have been the major factors of low human occupancy.

Major Outbreaks of Concentration

There are four areas of intense folding on the surface, three of which are located in Eurasia.

  • The major focus is on East Asia, especially Japan, Korea, and eastern China. It accounts for more than a quarter of the world’s population. Among the causes of high density are favorable climatic conditions for agriculture, flat relief, years of employment, and cultural and religious traditions which favor large families engaged in agricultural activities.
  • The second focus population is located in South Asia, in countries like India, Indonesia, Bangladesh, and Pakistan, where besides major cities, there is a predominantly rural population heavily concentrated.
  • The third focus is constituted by most of Europe, including west-central Russia. The physical conditions are favorable; the largest proportion of land is dedicated to agriculture. But most human levels are the result of the development of secondary and tertiary activities (industry, commerce, and services).
  • The fourth focus of the population is located on the northeast coast of North America. It highlights the great American megalopolis stretching from Boston to Washington.

Out of these four areas, there are large cities such as Mexico City, Sao Paulo, Buenos Aires, etc., whose main characteristic is the concentration of population in relation to the surrounding areas of low occupancy.

Intermediate Densities

These are regularly occupied areas and promote the emergence of high concentrations. The main ones are:

  • The east of Australia and New Zealand.
  • The Nile Valley, South Africa, and the Gulf of Guinea in Africa.
  • Around Los Angeles-San Francisco, around Vancouver, and the Anglo-American central plains.
  • The Central Valley of Chile, where Santiago is located.
  • The central plains of South America and the northeastern Brazilian coast.
  • The highlands of Central and Northern Andes from La Paz in Bolivia to the north in Peru, Ecuador, Colombia, and Venezuela.

Growth of World Population

1 – The population of our planet has doubled since 1950 and is not homogeneous, has never had a steady rate, showing decreasing periods and/or increasing more or less rapidly. This is called demographic.

2 – Demographic trends can be divided into two stages: The first is characterized by very slow population growth but rising, parallel to the expansion of economic resources. This extended period was called by the discovery, development, and refinement of tools, the development of agriculture, and the domestication of animals, that is, marked by the first economic innovations. The second is characterized by high population growth. This has been produced by changes from the second half of the eighteenth century because of the agricultural, industrial, and technological revolutions. These revolutions allowed to obtain food surpluses with which hunger and decreased labor release of agricultural activities, which began to deal with industrial and commercial activities.

3 – The rapid population growth occurred in recent decades is the result of multiple causes. The main factor responsible was the decrease in mortality. This decline has occurred as a result of medical advances, economic and technological developments that facilitated the disappearance of epidemics and the spread of new manufacturing techniques. The spread of this progress in developing countries was very fast, and with birth rates were high, there was what is known worldwide as the population explosion.

4 – While the growth rate reached its maximum value between 1965 and 1970, the population continued to grow strongly for two reasons.

5 – Africa is the continent with more growth. Its population grew from 220 million in 1950 to 818.0 million in 2002. This is because the mortality rate has begun to decrease, but the fertility rate has remained stable or increased.

6 – Asia is the continent where over half the world’s population lives. A special case is China, which decreased its growth rate dramatically. Its fertility rate dropped from 6.5 children per woman in 1968 to 2.3 in 1980 and 1.8 in the present. Within the family planning, various measures were implemented, including the one-child policy, applying sanctions for not complying with government directions.

7 – The Latin American population is also increasing fairly rapidly but not uniformly or predictably. The high population growth rates are due to the continued decline in mortality and persistent high fertility rates.

8 – In developed countries, the percentage of the population is declining; this is because fertility rates have fallen below the level Replacement: 2.1 children per woman. Europe is a special case within the group of developed countries because their growth rates are less than 1% annually, and there are countries with negative values, such as Germany, Italy, etc. This situation is due to low birth and mortality levels rising as a result of an aging structure.

9 – The theory of the pessimists, heirs to the theory of English economist Thomas Malthus, made in the late eighteenth and early nineteenth century, argued that the population grew at a geometric doubling every 25 years. As food resources increased in arithmetic progression. The imbalance between population growth and food production will decline progressively and caused hunger and misery in the world.

10 – On the other side are the optimists who believe that the world’s population in 2150 stagnated at around 10.8 billion people. They argue that our planet has enough resources to feed this growing population. Improvements in agriculture and technological innovations have managed to maintain the food supply large enough to meet global demand. Moreover, the price of staple foods has fallen markedly in recent years.

11 – In some areas, there is population pressure or overcrowding. This term is used for areas whose production is not sufficient to meet the normal requirements of its population.

12 – Infra-population refers to those territories that offer over-indulgence in food production. Given this distinction, experts have tried to determine the carrying capacity of our planet, bone, the maximum sustainable population and optimal sustainable population would allow the majority to live with their basic food needs met without compromising the ability of the land to support this population in the future.

13 – Development is fairly well-being of all people while preserving the sustainability of the environment, reducing bone environmental costs of development and the social costs of population growth. This option involves major changes in health, education, working conditions, social security, housing, etc.