World demography (natural and mechanical movement of population)

1. World demography (natural and mechanical movement of population)

I.B.Sarsenova

2. World Population: Growth & Trends

World Population: Growth & Trends

3. What’s demography?

The quantitative study of human populations.
Demographers study subjects such as the
geographical distribution of people, birth and
death rates, socioeconomic status, and age
and sex distributions in order to identify the
influences on population growth, structure,
and development.

4. Natural movement of population

Rate birth, death and natural growth

5. Mechanical movement of population Human migration is the movement by people from one place to another with the intentions of

settling, permanently or temporarily in a new location.
Migration of population
M = N of I – N of E

6. Take away concepts

Why is population growth so central to environmental problems?
What is the current population? What will it be in 2050?
What factors affect population growth rates?
How do growth rate compare in developed vs. developing
countries?
What is a "demographic transition? What are its stages?
Interpreting Population Pyramids.
Understanding modern demographic trends.

7. Why Population is so important

Thomas Malthus (1798)
Organism populations increase
exponentially, whereas the
“environment” is “fixed”
(actually decreases).
Factually correct, but a
complex problem...
Modern example: high
populations AND high quality
of life

8. Maltus’ 1st Axiom

“The power of population is indefinitely greater than the power in the earth to
produce subsistence for man.”
“Population, when unchecked, increases in a geometrical ratio (exponentially).
Subsistence increases only in an arithmetical ratio (linearly).”

9. World Population: 7.3 billion

As of Sept., 2014
World Population (1850-2007)
6
5
4
3
2
1
0
500
1000
1500
Year (AD)
(Super)exponential growth
0
2000
Population (in Billions)
7

10. Some observations...

Pre-19th century growth rates
were ~0.2%/yr
<1 billion people.
Pop. doubled in 300yr.
140 million died of plague: 6th,
14th, and 17th centuries.
Replaced in a few centuries.
Population increased after
Renaissance
Modern era population
explosion: post-1960

11. More...

Population growth after
1800’s ranged 1.2-1.9%!
Super-exponential
growth
Post-1960 was first time
EVER that population
doubled within a
generation

12. Likely population by 2050: 9 billion

13. Toward “logistic growth”

Levels off
eventually
population
time

14. Factors affecting Growth Rate

Growth rate = Birth Rate - Death Rate
1.1% = 1.9% - 0.8% (as of 2012)
Of these the Birth Rate is the most important
contributor, specifically the Fertility Rate
(#children/woman)
Why? Because death rates have stabilized...

15. Calculating Growth Rates (r)

Nt = Noexp(r t)
where No= pop. at time t, Nt = pop at later time (t), and r is
the growth rate, and t is time in years.
Rearranging to solve for r:
(Nt /No) = exp(r t)
r = ln(Nt/No) / t
Example: with current population of 7 billion, 1%
growth rate = 70 million new people/year.
(equiv. to Turkey or Malaysia)

16. Factors affecting Birth Rate

Global BR = 1.9% (95% in developing countries).
Lessons on population control from Thailand, South
Korea, Japan, India, and China:
Invest in Family Planning
Reduce poverty
Elevate the status of women

17. Factors affecting Death Rate

Global DR = 0.8% (equal between developing and
developed countries)
Low death rates due to:
medical treatments,
better food supplies and nutrition,
improvements in sanitation, and
access to clean water
Lower DR is the main reason for the global population
increase

18. Population Projections

Current ~7.3 billion (and
rising), growth rate:
1.1% (and falling…).
Projected 2050
population: 9 billion
Using modern growth
rate: Calculated pop.
by 2050: ~11 billion.

19. Where people live

20. Population growth rates

21.

22. Demographic Transition

Refers to the impact of economic development on
birth and death rates.
Responsible for the gradual reduction in pop growth
rates during the late-20th century
First noted by demographers for changes in 19thcentury Europe, the DT is a critical shift in population
growth and age structures that differentiate
developed nations from developing nations

23. Four stages of DT

1.
2.
3.
4.
The Preindustrial Stage when there is little population growth
because harse social conditions lead to both high death and high
birth rates.
The Transitional Stage, when industrialization begins and health
care improves, resulting in lowered death rates, but birth rates
remain high. Most of the developing world here.
The Industrial Stage, when the birth rate drops due to
modernization (and its accompanying social changes). Many
developed countries and a few developing countries here.
Finally, the Postindustrial Stage is recognized by further reductions
in birth rates, approaching or even below zero population growth.
Approximately 13% of the world population (mostly European
countries) is in this stage.
A complete DT exhibits both declining birth and death rates

24. Demographic Transition

When is the period of maximum population growth rate?

25. Demographic Transition

Stage 1: Death rates and birth rates both high.
Stage 2: Fall in death rates, Population increases.
Stage 3. Decline in birth rate stabilizes population.
Stage 4. Birth and death rates both low,
population stable.
Stage 5 (new). Higher death rates than birth rates,
populations contract.

26. Population Pyramid

Age
Population in age class

27. 2) Transitional Stage

2.9% growth rate; 4.8 births/woman; 43% population under 15 yrs

28. Why is this group so important?

Largest segment of population today..
“bottom billion” - world’s poorest
Will be even larger in near future because most of population is under
childbearing age (<15 yrs).

29. Population Momentum (also population lag effect)

Phenomenon that population will continue
to grow for decades even after total
fertility rates equal only the replacement
rate...
Due to weighting of age structure towards
the young…
So, work toward zero population growth...

30. 3) Industrial Stage

1.9% growth rate

31. 4) Early Postindustrial

0.1% growth rate; 1.8 births/woman; 18% of population under 15 yrs

32. 4) Late Postindustrial

-0.1% growth rate; 1.2 births/woman; 14% population under 15 yrs

33. Population Pyramids for the four demographic transition phases

34. China’s past and future population pyramid

35. Views from Joel Cohen’s 1995 book “How Many People Can the Earth Support?”

1.
Make a bigger pie: Increase human productive
capacities through technology and innovation.
2.
Put fewer forks on the table: Reduce numbers and
expectations of people through such means as
family planning and vegetarian diets.
3.
Teach better manners: Change the terms of
people’s interactions through improved planning
and government to enhance social justice.

36. Global Population Growth Is Driven by Developing Countries.

World Population (in Billions): 1950-2050
Source: United Nations Population Division, World Population Prospects: The 2006 Revision.
© 2007
POPULATION
REFERENCE
BUREAU

37. Fertility Levels in Selected World Regions, 1950 and 2005

Children per woman
6,7
1950–55
5,9
5,9
2005
5,1
3,5
2,5
2,7
2,6
2,0
Africa
© 2006 POPULATION REFERENCE BUREAU
Asia
Latin
America/
Caribbean
North
America
1,4
Europe

38. An Important Global Issue Is the “Demographic Divide” – The Vast Gulf in Birth and Death Rates Among Countries.

Ethiopia and Germany: The Demographic Divide in 2007
ETHIOPIA
GERMANY
Total Population
77.1 million
82.3 million
Population below Age 15
33.0 million
11.9 million
Population Age 65 and Older
2.2 million
15.3 million
Annual Births
3.1 million
672,000
Annual Deaths
1.2 million
821,000
236,000
2,600
49 years
79 years
1.4%
0.1%
Annual Infant Deaths
Life Expectancy at Birth
Percent of Adults Ages 15-49 with HIV/AIDS
Source: Carl Haub, 2007 World Population Data Sheet.
© 2007 POPULATION REFERENCE BUREAU

39. In Many Developing Countries, Fertility Rates Are Stabilizing After Years of Decline.

Fertility Trends in Sub-Saharan Africa: 1980-2005
Source: United Nations Population Division and National Demographic and Health Surveys.
© 2007
POPULATION
REFERENCE
BUREAU

40. South Asia and sub-Saharan Africa Have the Highest Shares of Young Children who Are Underweight.

Prevalence of Underweight Children Under Age 5, by Country
Source: Carl Haub, 2007 World Population Data Sheet.
© 2007
POPULATION
REFERENCE
BUREAU

41. Vitamin A and Iron Deficiencies Are Also Prevalent Among Children Under Age 5.

Percent of Children Under Age 5 with Vitamin A and Iron Deficiencies, Selected Regions
Source: Disease Control Priorities Project, “Stunting, Wasting, and Micronutrient Disorders” (2006): Table 28.1.
© 2007
POPULATION
REFERENCE
BUREAU

42. Despite Rising Obesity Levels, Some Households in the United States Do Not Always Have Enough to Eat.

Percent of Households and Children Who Are Food Insecure, United States: 1998-2005
Source: U.S. Department of Agriculture, Economic Research Service, Household Food Security in the United States, 2005
(Economic Research Report No.29): Table 1-A.
© 2007
POPULATION
REFERENCE
BUREAU

43. Women in the United States Have More Children on Average Than Women in Europe.

Fertility Trends in Europe and the United States: 1980-2006
Source: National statistical agencies.
© 2007
POPULATION
REFERENCE
BUREAU

44. In Many Developing Countries, Fertility Rates Are Stabilizing After Years of Decline.

Fertility Trends in Sub-Saharan Africa: 1980-2005
Source: United Nations Population Division and National Demographic and Health Surveys.
© 2007
POPULATION
REFERENCE
BUREAU

45. Older People Are a Smaller Share of the Population in the United States Than in Europe and Japan.

Population Age 65 and Older, by Country
Source: Carl Haub, 2007 World Population Data Sheet.
© 2007
POPULATION
REFERENCE
BUREAU

46. Demographic Impact of HIV/AIDS

Impact on life expectancy
HIV infection rates

47. UN Millennium Development Goals

UN Millennium Declaration, Sept. 2000
Adopted by 189 countries
By 2015:
1.
2.
3.
4.
5.
6.
7.
8.
Eradicate extreme poverty & hunger
Universal primary education
Gender equality, empower women
Reduce child mortality
Improve maternal health
Combat HIV/AIDS and other diseases
Environmental sustainability
Global partnership for development

48. Religious: world and national Languages – Chinese – 1,2, Arabic – 422, Hindi – 366, English – 341, Spanish – 322, Bengali –

207, Portugal – 176, Russian – 167,
Japanese – 125, German – 100.
Official languages of the world – English,
Chinese, Arabic, Spanish, Russian, French

49. Thanks for attention!