Global Population Dynamics, Distribution and Migration Trends

Population: Definition and Historical Drivers

Population: a group of people who live in a territory or a place at a particular moment in time.

Which factors have determined the growth of the human population from the Neolithic Revolution onwards?

Factors include: the expansion of agricultural areas, the natural environment and its climate, and catastrophic events such as wars and epidemics.

Why was there such a large increase in the world’s population from the end of the 19th century? Because of the Industrial Revolution.

How many people were in the world in 2015? Approximately 7.3 billion.

Four Demographic Models

1. Old demographic regime: high birth rate, high mortality rate.
2. Transition regime: high birth rate, falling mortality rate (demographic transition).
3. Modern demographic regime: lower birth rate, very low mortality rate.
4. Regressive demographic regime: negative growth — very low birth rate, low mortality rate.

Population Distribution and Density

The world’s population is distributed very unevenly across the globe. Some regions are nearly barren while others are extremely populated.

High-density areas

1. Intensive agricultural areas: these areas have conditions suitable for large-scale food production and often require many people to work in them.
2. Areas with mineral resources: resource extraction attracts population and economic activity.
3. Services and industrial areas: cities in high-density areas are very large and often form true urban agglomerations known as conurbations.

Conurbations consist of a central city surrounded by other dependent cities.

Low-density areas

1. Deserts: absence of water and extreme temperatures make habitation difficult.
2. Rainforests
3. Boreal forests
4. Cold and hot desert areas
5. Mountainous areas
6. Extensive agriculture and livestock

Birth, Death and Fertility Rates

Birth rate: the total number of births per 1,000 inhabitants that occur during a year in a particular place.

General fertility rate: the number of children per woman aged 15–49.

Death rate: the total number of deaths per 1,000 inhabitants that occur during a year in a particular place.

Child mortality rate: the number of children in their first year of life per 1,000 live births who have died in a particular location.

Impacts of High Fertility (Example: 5 children per woman)

• Potentially higher national income per capita in some measures, but also increased public spending and taxation needs.
• Need to create more jobs for a growing workforce.
• Pressure on resources; prices may rise as a consequence of resource scarcity.
• Increased consumption and environmental impacts.

Demographic pressures can lead to overpopulation (sobrepoblación), emigration, very high birth rates in some regions, conflicts, and social stress.

Consequences of Increased Life Expectancy

1. Overpopulation (in contexts of high birth rates combined with lower mortality).
2. Ageing population: a higher proportion of elderly people.
3. Problems funding pensions and social welfare systems.

Migration: Types and Causes

Migration: the movement of people from their native country or place to other places.

Types by duration

• Short-term: seasonal (estacional) — a matter of months.
• Long-term: years or permanent relocation.

Types by destination

• Regional: e.g., Barcelona to Madrid.
• Continental: e.g., Spain to Portugal.
• Intercontinental: e.g., Morocco to Spain.

Causes of Migration

Causes include economic factors, wars and conflicts, religious, political, and ethnic (racial) persecution.