Chapter 2 The World Population Distribution, Density And Growth

Patterns Of Population Distribution In The World

The term population distribution describes how people are spread across the Earth's surface. This distribution is highly uneven. A vast majority of the global population resides in a relatively small portion of the planet's land area.

This imbalance is captured by the observation that roughly 90% of the world's population lives on only about 10% of its land. This highlights that some areas are densely packed with people, while others are almost entirely uninhabited.

The famous geographer George B. Cressey remarked on Asia's population, stating it "has many places where people are few and few place where people are very many." This statement aptly describes the global population pattern as well.

A significant concentration of the world's population is found in a few countries. The 10 most populous nations in the world account for approximately 60% of the total global population. Notably, six of these countries are located in Asia:

• China
• India
• United States
• Indonesia
• Pakistan
• Brazil
• Nigeria
• Bangladesh
• Russia
• Mexico

Analyzing these patterns helps in understanding the demographic landscape of any region and the factors that influence where people choose to live.

Density Of Population

Population density is a metric used to understand the relationship between a region's population and its land area. It measures the number of people living per unit of area, providing insight into how crowded a place is. Each unit of land has a finite capacity to support a population, known as its carrying capacity.

It is typically expressed as the number of persons per square kilometer (persons/sq km).

The formula to calculate population density is:

Population Density = $ \frac{\textsf{Total Population}}{\textsf{Total Area}} $

Answer:

As per global data, Asia has the highest population density among the continents, primarily due to its vast fertile river plains, extensive industrialization, and long history of human settlement.

Factors Influencing The Distribution Of Population

The uneven distribution of the global population is not random. It is influenced by a combination of geographical, economic, and socio-cultural factors that make certain areas more attractive for human settlement than others.

I. Geographical Factors

These relate to the physical characteristics of a location.

• Availability of Water: Water is fundamental for human survival and activities like agriculture and industry. Consequently, river valleys such as the Nile, Ganges, and Yangtze are some of the most densely populated regions in the world.
• Landforms: People generally prefer to live on flat plains or gentle slopes. These areas are ideal for farming, building infrastructure like roads and factories, and establishing settlements. In contrast, mountainous and rugged terrains, like the Himalayas, hinder development and are sparsely populated.
• Climate: Extreme climates—very hot, cold, or wet—are inhospitable. Regions with moderate, comfortable climates without significant seasonal variations, such as the Mediterranean, tend to attract larger populations.
• Soils: Fertile soils are crucial for agriculture. Areas with rich, loamy soils can support intensive farming and, therefore, a larger population. Regions with poor, infertile soils tend to be thinly populated.

II. Economic Factors

These factors relate to economic opportunities and livelihood.

• Minerals: The presence of valuable mineral deposits can lead to the establishment of mining operations and related industries. These activities create jobs, attracting skilled and semi-skilled workers and leading to high population density. The Katanga-Zambia copper belt in Africa is a prime example.
• Urbanisation: Cities are hubs of economic activity, offering superior employment opportunities, educational institutions, healthcare facilities, and modern amenities. The "pull" of city life leads to significant rural-to-urban migration, causing cities to expand rapidly.
• Industrialisation: Industrial belts create a wide array of job opportunities, not just for factory workers but also for professionals in transport, banking, education, and healthcare. This concentration of employment attracts a large and diverse population. The Kobe-Osaka industrial region in Japan is a classic example of a densely populated area due to industrialization.

III. Social And Cultural Factors

These factors are linked to human society and culture.

• Religious/Cultural Significance: Places of religious or cultural importance often attract people, becoming centers of population. Cities like Jerusalem, Varanasi, and Mecca are examples.
• Social and Political Stability: People tend to move away from places experiencing political turmoil, social unrest, or conflict. Conversely, regions known for peace and stability attract migrants, seeking security for themselves and their families.
• Government Policies: Governments can influence population distribution through policies, such as offering incentives for people to settle in sparsely populated areas or providing support for relocating from overcrowded cities.

Population Growth

Population growth refers to the change in the number of people residing in a territory over a specific period. This change can be positive (an increase) or negative (a decrease) and can be measured in absolute numbers or as a percentage. It serves as a key indicator of a region's economic development and social well-being.

Some Basic Concepts Of Population Geography

• Growth of Population: The absolute change in population numbers between two points in time. For instance, the difference between a country's population in 2010 and 2020.
• Growth Rate of Population: The change in population expressed as a percentage.
• Natural Growth of Population: The change in population due to the difference between births and deaths. It is calculated as:

  Natural Growth = Total Births – Total Deaths

• Actual Growth of Population: This considers the impact of migration in addition to births and deaths. It is calculated as:

  Actual Growth = (Births – Deaths) + (In-Migration – Out-Migration)

• Positive Growth: Occurs when the birth rate exceeds the death rate, or when there is a net inflow of migrants.
• Negative Growth: Occurs when the death rate surpasses the birth rate, or when more people emigrate than immigrate.

Components Of Population Change

There are three fundamental components that drive population change:

1. Births: The rate of births is measured using the Crude Birth Rate (CBR), which is the number of live births per thousand people in a year.

$CBR = \frac{Bi}{P} \times 1000$

Where, Bi = number of live births during the year, and P = mid-year population.

2. Deaths: The rate of deaths is measured using the Crude Death Rate (CDR), which is the number of deaths per thousand people in a year. Population growth accelerates when the death rate decreases.

$CDR = \frac{D}{P} \times 1000$

Where, D = number of deaths, and P = mid-year population. Mortality rates are influenced by a region's healthcare, economic development, and social structure.

3. Migration: The movement of people from one place to another, which directly alters the population size of both the origin and destination locations.

Migration

Migration is the movement of people across regions. The location people leave is the Place of Origin, and the location they move to is the Place of Destination. Migration can be permanent, temporary, or seasonal.

• Immigration: The act of moving into a new place. The individuals are called Immigrants.
• Emigration: The act of moving out of a place. The individuals are called Emigrants.

Migration is influenced by two sets of factors:

Push Factors: These are negative conditions that compel people to leave their place of origin.

• Unemployment
• Poor living conditions
• Political instability or conflict
• Harsh climate or natural disasters
• Epidemics

Pull Factors: These are positive conditions that attract people to a new destination.

• Better job opportunities
• Higher standard of living
• Peace and stability
• Security of life and property
• Pleasant climate

Trends In Population Growth

The world's population, now exceeding seven billion, grew at a very slow pace for most of human history. The major acceleration in population growth occurred only in the last few centuries.

• Following the advent of agriculture (8,000-12,000 years ago), the world population was a mere 8 million.
• By the first century A.D., it was still under 300 million.
• The expansion of world trade in the 16th and 17th centuries laid the groundwork for faster growth.
• Around 1750, at the start of the Industrial Revolution, the world population was about 550 million.

The Industrial Revolution marked a turning point. Technological advancements led to a dramatic increase in population. Key developments included:

• Mechanization: The steam engine provided a new source of power, boosting agricultural and industrial production, which could support a larger population.
• Medical Improvements: Scientific breakthroughs like inoculation against diseases and better sanitation drastically reduced death rates, especially infant and child mortality, leading to accelerated population growth.

Remarkably, the human population has increased more than tenfold in the past 500 years, with a fourfold increase in the 20th century alone.

Doubling Time Of World Population

Population doubling time is the amount of time it takes for a population to double in size at its current growth rate. It took over a million years for the human population to reach its first billion, but only 12 years to grow from 5 billion to 6 billion in the late 20th century.

This illustrates a significant reduction in doubling time over history. However, there are vast regional differences.

• Developed countries have very slow growth rates and therefore take a much longer time to double their population, if at all.
• Developing countries often have high growth rates and are doubling their populations much more rapidly. The majority of global population growth is concentrated in the developing world.

The projected increase in doubling time from 47 to 51 years suggests a global slowdown in growth rates, but the absolute number of people added each year remains enormous.

Spatial Pattern Of Population Change

Population growth rates vary significantly across the globe. A strong negative correlation exists between economic development and population growth; generally, the more developed a country is, the lower its population growth rate.

While a global annual growth rate of 1.2% might seem small, it has a massive impact when applied to a population of billions. Even with declining growth rates, the total population continues to increase by tens of millions each year because the base population is so large.

This table highlights that while growth has slowed in most regions, Africa's growth rate has actually increased, making it the continent with the fastest-growing population.

Impact Of Population Change

Population change has profound consequences for society and the environment.

A modest increase in population can be beneficial for a growing economy by expanding the workforce and consumer market. However, excessive population growth beyond a region's carrying capacity leads to significant challenges, most notably the depletion of resources such as water, forests, and minerals.

Conversely, population decline can also be a cause for concern. It may signal that the resources that once supported a larger population are no longer sufficient, or it could lead to economic stagnation due to a shrinking workforce and aging population.

Health crises can also severely impact population trends. For example, the HIV/AIDS epidemic in parts of Africa and the former Soviet Union has led to increased death rates and reduced life expectancy, thereby slowing population growth in those regions.

Demographic Transition

The Demographic Transition Theory is a model used to describe and predict how a country's population changes over time. It posits that as a society develops from a rural, agrarian, and illiterate state to an urban, industrial, and literate one, it undergoes a transition from high birth and death rates to low birth and death rates. This process occurs in several stages, collectively known as the demographic cycle.

The model is typically broken down into three main stages:

Stage 1: High Fluctuating

• Characterized by high birth rates and high death rates.
• People have many children to compensate for high infant mortality caused by epidemics and unreliable food supplies.
• Population growth is slow and stable.
• Society is predominantly agricultural, with low life expectancy and low levels of technology. Two centuries ago, all countries were in this stage.

Stage 2: Expanding

• The death rate begins to fall sharply due to improvements in sanitation, healthcare, and food supply.
• The birth rate remains high, leading to a wide gap between births and deaths.
• This gap results in a period of rapid population growth, often called a population explosion. Many developing countries are currently in this stage.

Stage 3: Low Fluctuating

• Both birth rates and death rates decline to low levels.
• The birth rate falls as the population becomes urbanized, educated, and gains access to contraception, choosing to have smaller families.
• Population growth becomes slow, stable, or may even start to decline. Most developed countries are in this stage.

This theory demonstrates that humans can adapt their fertility rates based on socio-economic conditions.

Population Control Measures

Managing population growth is a crucial aspect of sustainable development. The most direct method is through family planning, which involves spacing or preventing the birth of children.

Key measures to control population include:

• Propaganda and Awareness: Educating the public about the benefits of smaller families and the challenges of overpopulation.
• Access to Contraceptives: Making modern contraceptive methods freely and easily available to all.
• Incentives/Disincentives: Governments can use policies like tax benefits for smaller families or other incentives to encourage population control.

In 1798, the economist Thomas Malthus proposed a theory that population tends to increase much faster (geometrically) than the food supply (arithmetically). He warned that this imbalance would lead to a "population crash" caused by famine, disease, and war (physical checks). Malthus argued that "preventive checks," such as delaying marriage and practicing abstinence, were a better way to control population. His theory underscores the urgent need to manage population growth to ensure the long-term sustainability of our resources.