Demography and Global Population Dynamics

Understanding Population and Demography

Population is the number of people inhabiting a territory. Demography is the science that studies the population and its characteristics.

Key Demographic Indicators

• Sex structure: The ratio between men and women is studied using population pyramids.
• Birth rate: Determines the number of births.
• Mortality: Determines the number of deaths.
• Natural or vegetative growth: The difference between the number of births and deaths.
• Emigration: The process of leaving one's country.
• Immigration: Entering a different realm or country.
• Net migration: The difference between the number of emigrants and immigrants.
• Real growth: The difference between natural growth and net migration.

Natural Population Movements

Birth Rates and Fertility

The Crude Birth Rate (CBR) is the number of people per thousand inhabitants, expressed in per mil (‰).

Mortality and Infant Health

The Crude Death Rate (CDR) represents fatalities per thousand inhabitants and is expressed per thousand (‰).

The CDR can be classified as:

• High: Above 30‰
• Medium: Between 10‰ and 30‰
• Low: Less than 10‰

To study mortality in more detail, researchers also use the infant mortality rate, which measures deaths of infants under 1 year compared with the total births that year. Infant mortality and fertility are studied together to understand how the child population is growing.

Global Migration Patterns

Migration movements are the movements of population from their countries of origin, involving emigrants and immigrants.

Types of Migration

• Depending on the region: Interior migration occurs when movements happen within a single country or region, and outside migration occurs if they are targeted outside the country.
• Depending on travel time: Seasonal migration lasts a few months. Temporary migration lasts from one to several years. Definitive migration involves not coming back.
• According to the reason: Voluntary migration occurs if the person makes the decision to emigrate, and forced migration occurs if people are compelled to leave.

Causes and Effects of Migration

Causes of Migration:

• Natural causes: Floods, droughts, earthquakes, etc.
• Human causes: These can be of various types, often based on economic grounds. People move to seek better living conditions. Migration can also be due to political issues. People who are forcibly moved are known as refugees.

Effects of Migration:

• In the origin regions, the structure of the population becomes unbalanced.
• In the receiving countries, there is a greater intercultural contact.