Welcome to Core Human Geography: Population!

Hello Geographers! This chapter is all about understanding people — how many of us there are, where we live, and why our numbers change. Population study is fundamental to Human Geography because every other topic (migration, settlement, resource use) depends on it. Don't worry if the numbers seem daunting; we will break down all the key rates and models step-by-step.

Ready to dive in? Let's go!

4.1 Natural Increase as a Component of Population Change

Key Population Rates & Definitions

To measure population change, we need a common language. These definitions are crucial for Paper 2.

  • Birth Rate (BR): The number of live births per 1,000 people in a population in a given year.
  • Death Rate (DR): The number of deaths per 1,000 people in a population in a given year.
  • Natural Increase Rate (NIR): The difference between the BR and DR. This is usually expressed as a percentage or per 1,000. It excludes migration.
  • Total Fertility Rate (TFR): The average number of children a woman is expected to have during her reproductive years (usually 15-49).
  • Replacement Level: A TFR of approximately 2.1 is needed to maintain a stable population (accounting for children who do not survive to adulthood).
  • Infant Mortality Rate (IMR): The number of deaths of infants under one year old per 1,000 live births. This is a crucial indicator of a country's development and healthcare quality.
Memory Aid: Rates are always 'per 1,000'

If you are calculating a rate (BR, DR, IMR), remember the answer is usually expressed as 'per thousand' (except for NIR, which is often a percentage).

Factors Affecting Fertility and Mortality

Population rates don't change randomly; they are influenced by a mixture of factors. You must be able to categorize these influences.

A. Factors Affecting Fertility Rates (Births)
  • Economic: In Low Income Countries (LICs), children are often needed as labour (farm work) and as insurance for old age (they support their parents). In High Income Countries (HICs), children are expensive and women have career opportunities.
  • Social/Cultural: Religion (some encourage large families), status of women (higher status and education often leads to lower TFR), customs (early marriage), and availability of family planning/contraception.
  • Political: Government policies (e.g., tax breaks for having children, or anti-natalist policies like China’s former One-Child Policy).
B. Factors Affecting Mortality Rates (Deaths)
  • Healthcare: Access to doctors, hospitals, clean water, sanitation, and immunisation programmes drastically lowers the Death Rate and IMR.
  • Diet and Nutrition: Chronic malnutrition or widespread infectious diseases (like HIV/AIDS) increase mortality.
  • Environmental: Exposure to pollution, natural disasters, or clean water shortages increases the DR.
  • Political/Conflict: War, political instability, and lack of governmental investment in public health lead to higher mortality.

Key Takeaway 4.1: Natural Increase is calculated simply (BR - DR), but the rates themselves are controlled by complex social and economic conditions, especially healthcare and the role of women.

4.2 The Interpretation of Age/Sex Structure Diagrams

Population Structure (Age and Gender)

The best way to visualize a population is using an Age/Sex Structure Diagram, often called a Population Pyramid. These diagrams show the percentage or number of males and females in different age groups (cohorts).

Interpreting the Shape:
  • Wide Base: High Birth Rate (typical of LICs/Stage 2 DTM). Suggests a youthful population.
  • Narrow Base: Low Birth Rate (typical of HICs/Stage 5 DTM).
  • Concave Sides: High Death Rate or IMR (lots of people dying early).
  • Bulge in the Middle: Often represents a 'baby boom' generation or the influx of economic migrants (usually young working adults).
  • Wide Top: High life expectancy and low death rates in old age (suggests an ageing population).

Dependency and the Dependency Ratio

A population's structure determines the proportion of people who are economically productive versus those who rely on them (dependants).

  • Productive Age Group: Usually defined as 15 to 64 years old.
  • Dependants:
    • Youth Dependants: 0 to 14 years old.
    • Elderly Dependants: 65+ years old.

The Dependency Ratio measures the burden on the working population.

\[ \text{Dependency Ratio} = \frac{\text{Population Aged 0-14} + \text{Population Aged 65+}}{\text{Population Aged 15-64}} \times 100 \]

Analogy: Imagine the productive age group pays all the bills. The higher the dependency ratio, the more people they have to support, meaning higher taxes or stress on public services (like schools and pensions).

4.2 The Demographic Transition Model (DTM)

Understanding the Model

The Demographic Transition Model (DTM) explains how birth rates (BR) and death rates (DR) change over time as a country develops economically. This results in five distinct stages of population growth.

Stages of the DTM (The 5 Steps)

Stage 1: High Stationary

  • BR: High (due to lack of family planning, high IMR, need for labour).
  • DR: High (due to disease, famine, poor sanitation).
  • NIR: Stable or very slow increase.
  • Example: Isolated tribes, no country is truly here today.

Stage 2: Early Expanding

  • BR: Stays High.
  • DR: Falls rapidly (due to improved food supply, sanitation, and basic medical care).
  • NIR: Very rapid increase (a population 'explosion').
  • Example: Many LICs (e.g., Afghanistan, Niger).

Stage 3: Late Expanding

  • BR: Falls rapidly (due to urbanization, rising incomes, better female education, and contraception access).
  • DR: Continues to fall slowly.
  • NIR: Increase slows down significantly.
  • Example: Many MICs (e.g., India, Brazil).

Stage 4: Low Stationary

  • BR: Low (women choose careers, high cost of raising children).
  • DR: Low and stable.
  • NIR: Stable or very slow increase/decrease.
  • Example: Most HICs (e.g., USA, France).

Stage 5: Declining

  • BR: Falls below the Death Rate (sub-replacement fertility).
  • DR: May slowly rise (due to an ageing population).
  • NIR: Natural decrease (population starts to shrink).
  • Example: Japan, Germany, Italy.
Critical Appreciation of the DTM (Limitations)

While useful, the DTM is a model and has limitations:

  1. Original Based on HICs: It was based on the experience of Western Europe. Developing countries today may skip stages due to rapid medical advancement (e.g., vaccines arriving quickly).
  2. Ignores Migration: The model only accounts for natural change; mass migration can change the population structure instantly.
  3. Time Scale Varies: The transition took 200 years for the UK, but only decades for some Asian countries.
  4. Government Policy: It doesn't account for policies (like China's) which force demographic change rapidly.

Issues Arising from Population Change

Rapid growth (Stage 2/3) or decline (Stage 5) creates huge challenges:

A. Youthful Populations (High Youth Dependency)
  • Challenge: Too many young dependants (0-14).
  • Impacts: Strain on education system and basic services (healthcare). Future unemployment risk if jobs aren't created fast enough. High pressure on agricultural land.
  • Example: Niger has one of the world's most youthful populations.
B. Ageing Populations (High Elderly Dependency)
  • Challenge: Too many elderly dependants (65+).
  • Impacts: Strain on pension systems and specialised healthcare (geriatric care). Labour shortages (the working base shrinks). Need for increased immigration.
  • Example: Japan has the world's highest proportion of elderly people.

Key Takeaway 4.2: The DTM shows development reduces death rates first, then birth rates. Extreme structures (youthful or ageing) place different types of strain on a country's resources.

4.3 Population-Resource Relationships

The Concept of Food Security

Food Security means that all people, at all times, have physical and economic access to sufficient, safe and nutritious food that meets their dietary needs and food preferences for an active and healthy life.

Causes and Consequences of Food Shortages
  • Causes: Climate hazards (droughts, floods), war/conflict (disrupting supply chains), poverty (inability to buy food), pests/diseases (crop failure), and poor land management (soil degradation).
  • Consequences: Malnutrition, starvation, high IMR, large-scale migration (environmental refugees), and social unrest/conflict.
Role of Technology and Innovation

Technology helps sustain populations by increasing food production (intensification):

  • The Green Revolution (1960s/70s): Introduced High Yield Varieties (HYVs) of crops, mechanisation, and agrochemicals (pesticides/fertilisers), leading to massive increases in global output.
  • Modern Tech: Genetic modification (GM crops), precision agriculture (using GPS/drones to manage crops), and drip irrigation (conserving water).

Carrying Capacity and Optimum Population

Carrying Capacity (CC)

The Carrying Capacity is the maximum number of individuals that an environment can support indefinitely without long-term damage or degradation to the environment.

Analogy: It’s the maximum number of customers a small restaurant can serve comfortably with its current staff and kitchen size without running out of ingredients or collapsing from stress.

CC can be increased through technology (e.g., building a bigger kitchen, importing better ingredients).

Optimum Population (OP)

The Optimum Population is the population size that, working with all available resources, achieves the highest standard of living and quality of life for its people.

  • This is a theoretical concept — it’s hard to define the “highest quality of life.”

1. Overpopulation: When the population size is too large relative to the resources and technology available, leading to a decline in the standard of living. Resources (like water and housing) are stretched thin.

2. Underpopulation: When the population size is too small to efficiently develop its resources, leading to an under-utilization of potential. It often results in labour shortages.

Critical Evaluation Point: Whether a country is overpopulated is not just about the number of people, but how they consume. The USA (small population relative to resources) consumes far more resources per capita than Bangladesh (high population density), suggesting HICs may suffer from economic overpopulation due to excessive consumption.

Key Takeaway 4.3: Food security and carrying capacity link population size directly to the environment. Optimum population is the sweet spot, but high consumption in developed nations often makes resource issues a global problem.

4.4 The Management of Natural Increase (Case Study Requirement)

Governments use various policies to manage population growth, often in response to perceived overpopulation or underpopulation (ageing).

Types of Policies

  • Anti-Natalist Policies: Aim to decrease the birth rate (e.g., China’s One-Child Policy, providing free contraception, promoting female education).
  • Pro-Natalist Policies: Aim to increase the birth rate (e.g., France offering cash payments or tax breaks for having children, subsidised childcare).

Case Study Requirements

For your exam, you must study one country’s population policy regarding natural increase. This case study must:

  1. Describe the policy (Was it pro- or anti-natalist?).
  2. Show the difficulties faced in implementing the policy (e.g., cultural resistance, gender imbalance, cost).
  3. Evaluate the attempted solution(s) (Did it work? What were the unintended side effects?).
  4. Include attempts to alter the natural increase rate (e.g., incentives/fines).
  5. Include attempts to manage the results of population change (e.g., dealing with a growing elderly population, or addressing the shortage of women).

Did you know? Singapore is a great example of a country that had a strong anti-natalist policy in the 1970s (Stop at Two) but had to reverse to a pro-natalist policy (Have Three or More) when they realised their population was ageing too rapidly. This shows management policies are often flexible and change over time.

Quick Chapter Review Checklist

You should now be able to:

  • Define BR, DR, NIR, TFR, and IMR.
  • Explain how social, economic, and political factors drive fertility and mortality.
  • Interpret population pyramids and calculate the Dependency Ratio.
  • Describe and critically evaluate all 5 stages of the DTM.
  • Define and differentiate between Optimum Population, Overpopulation, and Underpopulation.
  • Explain food security and the role of technology in sustaining population.
  • Apply your knowledge using a specific case study of a population policy.

Great job! Understanding population is the first crucial step in Core Human Geography. Now practice interpreting those pyramids!