Population Change (DP IB Geography)
Revision Note
Demographic Transition Model
Since the Industrial Revolution (1850s), no two country's population have changed in the same way
However, some similarities can be seen in population growth
These similarities are shown by the demographic transition model (DTM)
The model illustrates 5 generalised stages of population change that countries pass through as they industrialise
It shows how birth and death rates change over time and its effects on the overall population
The gap between the birth rate and death rate is called natural change (either an increase or decrease in population)
Demographic transition model
Description of DTM
Stage | 1 | 2 | 3 | 4 | 5 |
---|---|---|---|---|---|
Stage Name | High stationary | Early expanding | Late expanding | Low stationary | Decline |
Population Change | Stable | Very fast natural increase | Increase slows | Very slow increase | Natural decrease |
Birth Rate (BR) | High (~35/1000) | High (~35/1000) | Falls quickly (to ~15/1000) | Falls further and remains low (to ~10/1000) | Falls very low and below DR |
Explanation of BR Change | Lack of birth control; poor education around family planning; lots of children born to replace those that die due to high infant mortality rates; children needed to help work on the land | Improvements in family planning, birth control and infant mortality rates | Further availability of contraception and career advancement for women so children turn from economic asset to burden | More elderly population so smaller proportion of women of reproductive age | |
Death Rate (DR) | High (~35/1000) | Falls quickly | Still falling but slower | Low | Climbs slightly higher than BR |
Explanation of DR Change | Poor medical care, lack of sanitation, poor diets and high rates of disease | Improved sanitation, medical care and food and water supply | Reliable food supply and healthcare established | The ageing population has a higher proportion of people reaching life expectancy | |
Application of Model to Contrasting Contemporary Settings | Remote tribal groups in Amazon rainforest | Poorest LICs, such as Gambia, Mali, and Niger. E.g., in 2022, Niger’s BR was 44/1000 and its DR was 7.5/1000, suggesting it is at the end of stage 2 | Fast-industrialising countries such as India, Brazil, and Mexico. | HICs such as the UK, USA, and France. | Very highly developed countries, such as Japan. |
The strengths of the model include:
It can be applied to different settings
It can help demographers plan for predicted future changes
The limitations of the model include:
Developed in 1929, when many countries were still under colonial rule. The model assumes all countries will follow the same pathway through the stages
It fails to take into account the effects of globalisation, migration, natural disasters, pandemics, wars and government policies that impact birth rates, e.g. China’s one-child policy
It fails to take into account the decline in fertility rates
It is too Euro-centric. The model is based on data from 3 countries (England, Wales and Sweden) that industrialised between the 18th and 20th centuries
It is difficult to apply to LICs that are currently industrialising in a shorter time frame due to globalisation
Current LICs population change has differences:
Birth rates in stages 1 and 2 are generally higher in LICs
Currently only 1 African country (Niger) has a birth rate of 45 /1000 or more
In 2000, 14 African countries were in this situation
Death rates have fallen quickly for different reasons
Availability and use of modern medicine, particularly vaccinations, has lowered mortality rates significantly
However, AIDS has caused the death rate to rise in some countries, particularly sub-Saharan Africa
Base populations are different
With the overall global growth in population, LICs have a much bigger base population to start with, making the impact of high growth bigger in stage 2 and early stage 3
When India and China entered stage 2, no developed country had a population close to that size
Fall in fertility rates have been steeper for countries in stage 3
Mainly due to the availability, reliability and education of modern contraception
Differences in demographic transitions
Not all countries follow the classic model of transition
France essentially skipped stage 2, as their birth rate declined in line with death rates
Mexico saw an increase in births in stage 2 as maternal health care improved
Ireland saw falling birth rates and rising death rates in stage 2 because of emigration after the Great Famine of 1845-9
Types of demographic transition
Natural Change
Natural population change occurs when birth and death rates differ in a place
If birth rates are higher than death rates then there will be a natural increase
If death rates are higher than birth rates there will be a natural decrease
The crude birth rate is heavily influenced by the age structure of a population
For instance, in 2022 the crude birth rate varied globally
The overall global crude rate was 17/1000
Highest was Niger with 46.86/1000
Lowest was South Korea and Hong Kong with 5/1000
Natural change is calculated as a % by subtracting the crude death rate from the crude birth rate
Population also changes when people migrate into and out of an area
Population change is also influenced by the following key vital rates:
Fertility rate
Infant mortality rate
Replacement level
Net production rate
Examiner Tip
There are plenty of key terms here that will be important to learn. You may not get asked directly to define them but if you can use them with confidence in your exam answers you will be credited with more marks for knowledge and understanding.
Fertility rate
For more accurate measures of fertility, the fertility rate and the total fertility rate (TFR) are used
These rates apply to women within the main reproductive age range of 15-49 years, rather than to the whole population
This makes for a more accurate measure of fertility than just the birth rate
Fertility rate is:
The number of live births per 1000 women aged 15-49 years in a given year
Total fertility rate is:
The average number of children that would be born alive to a woman during her lifetime - total family size
This assumes that she passes through her child-bearing years conforming to the age-specific fertility rates of a given year
Factors affecting fertility can be grouped into four main categories:
Categories Affecting Fertility Rates
Demographic | Other factors, such as infant mortality rates, influence fertility (high rates of birth to compensate for expected deaths) |
Social/cultural | Traditions still dominate in some societies - religion, preference for male children, high number of children to show virility etc. Education, especially female literacy, helps lower fertility |
Economic | In some LICs children are considered economic assets, but as a cost in HICs. This child dependency for many years is a factor in whether to begin or extend a family |
Political | Government attempts to change the rate of population growth for economic and strategic reasons either through incentives to encourage growth or sanctions to reduce growth |
The United Nations has predicted that:
The world's population is expected to increase by nearly 2 billion persons in the next 30 years, from the current 8 billion to 9.7 billion in 2050 and could peak at nearly 10.4 by 2100
Generally, as health improves the mortality rate in the population decreases, and typically there is an accelerated population growth
However, fertility levels have been falling faster than expected:
The global average fertility rate is around 2.3 children per woman today
Yet 50 years ago, the global fertility rate was double, with rates of 4.5 to 7 children per woman across the globe
Since then, LICs and MICs have seen rapid falls in fertility, partly due to:
Increased status and well-being of children
Empowerment of women within society and relationships through strengthening:
Access to education
Recognition and participation in the labour force
Improved women's rights
Declining global fertility rates over time
Replacement level fertility is the level at which those in every generation have just enough children to replace themselves in the population
A total fertility rate of 2.1 children is usually considered a replacement level, below this, and countries see a population decline
Examiner Tip
When writing about the factors affecting population change, consider that each factor might change population in different ways depending on where in the world it is. For e.g. population policies restricting birth rates operate in some parts of the world but in other countries, governments are trying to increase birth rates to stimulate growth in young populations. The more you can explain the changes over space the more marks you will achieve.
Life expectancy
This measure indicates the average age of death in a population
In the past, life expectancy was around 30 years in all regions of the world
Since the 17th century, life expectancy has steadily increased, although it is unevenly spread
Industrialising countries saw the largest increase through improved health and access to medicines
Since the 1900s, average, global life expectancy has risen to above 70 years, although it still varies within and between countries
in 2021, Japan had the highest life expectancy at close to 85 years and Chad was the lowest at 52.5 years
Globally, the African continent has the lowest average life expectancy at 61.7 years and Oceania the highest at 79.9 years
Countries with a life expectancy of below 60 years are found in Sub-Saharan Africa due to conflict, poverty and the AIDS virus
Yemen, Haiti and Afghanistan have life expectancies of over 62 years, yet in 1950 they were below 37.5 years
Women live longer
Before the 19th century, this wasn't the case, as many women died in childbirth or complications from childbirth
In fact, the death rate between men and women was fairly equal
As countries developed, men became more vulnerable to cardiovascular diseases such as strokes and heart disease, through self-destructive lifestyles such as drinking and smoking
Men became less active as job roles changed from manual to desk work
Men are more likely to be involved in conflict and take bigger risks with their lives
Biologically, women are more resistant to disease and fat is laid down in the body differently than men
Environmental changes due to the reduction or eradication of infectious diseases
Examiner Tip
Do not assume that improved standards of living means a longer life expectancy. Whilst, good standards of living have improved life expectancy through better nutrition and access to healthcare etc. it isn't always the case. There are elderly people with cancer, arthritis, Parkinson's and Alzheimer's etc. across all levels of development. It is a contributing factor, not a given fact.
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