1. 8.1 Population Dynamics Starter
What is the current global human population?
What is the population of Thailand?
What is the population of Bangkok?

2. Human Population Growth

3. Human Population Growth
The world’s human population is now thought to be greater than 7 billion.
Although population is still increasing, the rate of increase is currently decreasing
Female fertility rate is decreasing
1990 global average = 3.3 children/lifetime
2002 global average = 2.6 children/lifetime *
In developing countries, AIDS related diseases are having a big impact on population
* Note that this is still above the replacement level. If current trends continue, it may fall below 2.0 children/lifetime before Does this mean population will decrease?

4. Total Female Fertility Rate (TFR)
Children/lifetime, according to CIA World Factbook 2013 database

5. The Impact of Increasing Population
More resources are needed to feed, clothe, care for, transport, entertain, etc. However, the resources used by the fastest growing sections of society (LEDCs) are much less than MEDCs. Fertility rate is decreasing and life expectancy is increasing. Social security (necessary to care for an aging population) is not necessarily increasing.

6. World Population Distribution

7. Population Changes
Areas where population is likely to continue increasing:
North America
Latin America
Areas where population is likely to fall:
China
Western part of Former Soviet Union
Areas where population is likely to increase, but at a much lower rate:
Sub-Saharan Africa
India and Pakistan

8. Demographics Studying how and why populations change.
Human population has undergone several phases of change throughout history.
Linear growth (until ~1900)
Exponential growth (~1900 to now)
Predicted growth (from ~2020)
Continued increase.
Stabilization.
Most accepted by scientists.
Decrease.
By Tga.D based on Aetheling's work [CC BY-SA 3.0 ( or GFDL ( via Wikimedia Commons

9. Causing Change Births - cause populations to increase.
Example:
Births
Deaths
Population
Hungary (2015)
91 690
Births - cause populations to increase.
Crude Birth Rate (CBR)
The number of births per thousand individuals per year.
Total births in a year x1000
Total Population
Deaths - cause populations to decrease
Crude Death Rate (CDR)
The number of deaths per thousand individuals per year.
Total deaths in a year x1000
CBR = (91 690/ ) x1000
CBR = x 1000
CBR = 9.33
In 2015, Hungarians gave birth to 9.33 children per 1000 people.
CDR = ( / ) x 1000
CDR = x 1000
CDR = 13.41
In 2015, of every 1000 Hungarians died.

10. Measuring Change Natural Increase Rate - the percentage
a population grows per year.
NIR = (crude birth rate - crude death rate) 10
Using the data from the previous slide…
NIR = ( ) / 10
NIR = / 10
NIR = %
In 2015, Hungary’s population was declining (negative) by just less than half
a percent.
An alternative means of investigating population change is to analyze:
Total Fertility Rate, which is the average number of babies that a woman has
throughout her life.
By Kwamikagami [CC BY-SA 3.0 ( via Wikimedia Commons

11. Predicting Change DT (years) = 70/natural increase rate
Doubling Time - the period of time required for a population to become twice as large.
DT (years) = 70/natural increase rate
Using the calculations from the previous slide…
DT = 70 /
DT = years
Since this value is negative and Hungary’s population is
declining, it will NOT double.
Indonesia, however, has a CBR of 16.4 and a CDR of 6.4 resulting in a NIR of 1%. This will lead to a doubling time of 70 years (70/1). So, in 70 years, Indonesia’s population of almost will be more than half a billion people.

12. Calculations
Crude Birth Rate (CBR) (births/1000 people) = total number of births x 1000 total population
This does not consider the age or sex structure of a society
Crude Death Rate (CDR) (deaths/1000 people)
= total number of deaths x
total population
The highest birth rates are in LEDCs. In MEDCs birth rates (and fertility rates) have fallen

13. Calculations
Total Fertility Rate (TFR) = average number of births per woman per lifetime

14. Calculations Natural Increase Rate (NIR) = CBR - CDR
Doubling time (years) =
percentage growth rate
Doubling time is the time it takes for a population to double in size, assuming growth rate remains constant and an average life expectancy of 70 years. It is sometimes called ‘The Rule of 70’.

15. Factors Affecting Fertility Rates
In general, the higher the level of education, the lower the number of children per family. LEDCs generally have introduced programmes to reduce birth rates (e.g. family planning clinics, sex education). Government imposed controls on birth rate have generally been unsuccessful (except perhaps in the case of China). Some MEDCs have introduced programmes to increase birth rate (e.g. Singapore, France). In general, as economic prosperity increases, birth rate decreases. Recession and unemployment are linked to reduced birth rate (due to parental perception that they cannot afford to bring up children). The higher the child mortality rate, the greater the perceived need to have more children.

16. Factors Affecting Death Rates
Improved health care leads to an aging population, but is not necessarily reflected by a reduced CDR. Longer life expectancy leads to a larger number of deaths at the same time.
CDR in Denmark = 11 deaths/ 1000 people
CDR in Mexico = 5 deaths/ 1000 people
LEDCs generally have low life expectancies and high death rates (although the trend is for improvements in both).
The CDR in LEDCs has however been increased due to the impact of AIDS.

17. Total MEDC pop (billions) Total LEDC pop (billions)
Calculations
Date
Total MEDC pop (billions)
Total LEDC pop (billions)
1800
0.3
0.7
1850
0.4
0.8
1900
0.6
1.1
1950
1.7
1960
0.9
2.1
1970
1.0
2.8
1980
3.3
1990
1.2
4.1
2000
1.3
5.0
2025
1.4
7.2
2050
8.0
Produce a graph to show the change in population of MEDCs and LEDCs over time.
Can you explain the patterns you see?

18. Calculations
Date
Growth Rate
(%)
Doubling time (years)
1960
1.4
1970
2.1
1975
1.9
1980
1.8
1985
1.7
1990
1995
1.5
2000
1.1
2005
1.2
If a town’s population has a natural growth rate of 2%, how long will its population take to double in size?
Copy and complete the following table to show doubling times of the global population
Source: World Bank

19. Population (millions)
Calculations
Copy and complete the following table. It shows approximate population data from 2008.
What do your calculations tell you about what is happening in each region?
Region
Population (millions)
Land area (km2 x106)
Births (millions)
Deaths (millions)
CBR
CDR
NIR
World
6000
131
121.0
55.8
Asia
3500 31
88.2
29.4
India
1000 3
29.0
10.0
Africa
730 29
30.7
Europe
22.7
8.5
8.2
N America
460
21.8
9.3
3.6
USA
270
9.6
4.3
2.4

20. Population Pyramids Wide base indicates high birth rate
Narrow base indicates low birth rate
Vertical sides indicate low death
Inward curving sides indicate high death rate
Lack of symmetry shows differences in birth and death rate between the sexes
Bulges or constrictions suggest high rates of migration or immigration, specific to age groups (or war)

21. The Demographic Transition Model

22. The Demographic Transition Model
Stage 1/2
Expanding
Stage 3
Expanding
Stage 4
Stationary
Stage 5
Declining

23. Using Population Models
You can use models over a range of scales and the factors are different at different scales
On the national scale, immigration and emigration are factors, whereas on the global scale they are not
There are so many variables to take into account that making accurate predictions is very tricky
Birth rate is affected by:
Existing age structure
Status of women in society
Level of education
Availability of family planning
Provision of child benefit
Death rate is affected by:
Existing age structure
Availability of food and clean water
Disease
War and conflict
Provision of healthcare

24. Using Population Models
UN Estimates of world population by 2100 vary widely depending on the assumed variables
The further we project into the future, the greater the disparity between the estimates
The widely quoted figure is 9 billion by 2050
14 billion
9 billion
5.5 billion

25. Using Population Models
The biggest challenge may not be dealing with global population growth, but with global population ‘greying’ in MEDCs and LEDCs
Currently MEDCs have around 4 workers per retiree, but by 2050 it is expected to be around 2
The solution may lie in:
Expanding the population of workers (increasing retirement age and getting more women into the workplace)
Increasing productivity
Persuading people to save more for their retirement
Do you think governments in MEDCs may be unwilling to implement such policies?

26. Questions
Describe the nature and implications of human population growth
Outline the factors that affect birth rates and death rates
Discuss the effectiveness of population models