agec 340 -- international economic development course slides for week 4 (feb. 2 & 4) population...

AGEC 340 -- International Economic Development

Course slides for week 4 (Feb. 2 & 4)

Population growth and demographic transition*

• What determines changes and differences in population growth, and in the proportion of people at each age?

* If you’re following the textbook, this material is in Chapter 4.

Some terminology: Demography and economics

• The English language can be very confusing!

•When talking about…• “demography”: study of population, also the population itself• “population growth”: increasing number of people• “demographics”: measured characteristics of the population “

• But also…• the “economy”: the prod. & cons. activities of a population• “economic growth”: increases in prod. & cons. per person• “economics”: a way of studying the economy

Population Growth Over TimeOur Textbook Picture:

Population Growth Across Countries Our Textbook Picture:

Is population growth a problem……or an opportunity?

• Pop. growth lowers the amount of available land and other kinds of capital per person,

• …but it raises the total size of the economy, which may offer some benefits of scale:

more opportunity to specialize & trade more innovators with new ideas a larger market to cover fixed costs

• on balance, pop. size itself is not really bad;but changes during transition can be awful!

World Population Growth,More vs Less developed countries

Percent change from previous year

0.0%

0.5%

1.0%

1.5%

2.0%

2.5%

3.0%

1951

1953

1955

1957

1959

1961

1963

1965

1967

1969

1971

1973

1975

1977

1979

1981

1983

1985

1987

1989

1991

1993

1995

1997

1999

2001

2003

Less Developed More Developed

Population data from the U.S. Bureau of the Census, International Data Baseretreived 4/21/05 from http://www.census.gov/ipc/www/idbnew.htmlin Online Demographic Aggregation

Prepared and copyright by Gene ShackmanThe Global Social Change Research Projecthttp://gsociology.icaap.orgCharts may be used freely.

Famine in China, 1958-1961:with quick catch-up afterwards!

Fast rise

Slow fall

meanwhile, in the richer countries

What drives population growth?

• The “demographic transition”:–population growth rates rise and then fall

…but what happens during the transition? –What initiates the change?–Do all countries follow the same path? –What determines the speed of change?

What happens during demographic transition? Our textbook picture is:

So what drives population growth is:

• The “demographic transition”:–population growth rates rise and then fall–driven by a decline in the death rate

– the “mortality transition”– followed by a decline in the birth rate

– the “fertility transition”

• Do all countries follow the same path?

Here’s the demographic transition for one specific country:

Source: Montgomery, Keith (2000), “Notes on the Demographic Transition.” Available online at www.uwmc.uwc.edu/geography/Demotrans/demtran.htm.

Crude Birth Rate (CBR): births per thousand people

Crude Death Rate (CDR):deaths per thousand people

what type of country is this? what caused these changes?

Each year’s “natural increase” in a populationis their total births minus total deaths


Crude Birth Rate (CBR): births per thousand people

Crude Death Rate (CDR):deaths per thousand people

How fast is population growth?

That was Sweden…

• Death rates began to fall after 1800– fell gradually from 25-30 per thousand– stopped falling at 10 per thousand in 1955

• Birth rates began to fall after 1825– fell gradually from 30-35 per thousand– reached death rate of 10 per thousand in

1980• Pop. growth went from 0.5 to 1.0 to zero pct./yr

And here it is again, in comparison with another country:


what type of country is this one?

The first country is Sweden… the second is Mauritius, an island off the coast of Africa

Population growth rates depend on both birth and death rates


Mauritius had very fast population growth after WWII, because of a very rapid decline in its death rate

How fast was Mauritius’s peak rate of population growth? When was it?

Fast mortality decline after WWII was driven by public health breakthroughs in many tropical countries

Reprinted from D.E. Bloom and J.G. Williamson, 1998. “Demographic Transitions and Economic Miracles in Emerging Asia.” World Bank Economic Review 12(3): 419-55.

…but now let’s compare Swedento a different country:

Sweden--Birth Rate

Sweden--Death Rate

Sources: Population Reference Bureau (www.prb.org). Underlying data are in 5-year intervals, from B.R. Mitchell, European Historical Statistics 1750-1970 (1976): table B6; Council of Europe, Recent Demographic Developments in Europe 2001 (2001): tables T3.1 and T4.1; CELADE, Boletin demografico 69 (2002): tables 4 and 7; F. Alba-Hernandez, La poblacion de Mexico (1976): 14; and UN Population Division, World Population Prospects: The 2002 Revision (2003): 326.

??--Birth Rate

??--Death Rate

Remember, population growth rates depend on both birth and death rates

Sweden--Birth Rate

Sweden--Death Rate

Sources: Population Reference Bureau (www.prb.org). Underlying data are in 5-year intervals, from B.R. Mitchell, European Historical Statistics 1750-1970 (1976): table B6; Council of Europe, Recent Demographic Developments in Europe 2001 (2001): tables T3.1 and T4.1; CELADE, Boletin demografico 69 (2002): tables 4 and 7; F. Alba-Hernandez, La poblacion de Mexico (1976): 14; and UN Population Division, World Population Prospects: The 2002 Revision (2003): 326.

??--Birth Rate

??--Death Rate

How did this country’s birth rate stay high for so long?How did that affect their population growth?

Africa’s demographic transition started late, and had a very high peak population growth rate

Source: Calculated from data in FAOStat (2007).

So what explains the historical mortality decline in today’s rich countries?


what kinds of disease are these? when were they reduced?

The first measles vaccine was introduced in 1968,

way after the disease stopped causing

many deaths

An example of mortality decline in the US


Within the U.S., whose mortality declined the most?

The 1918 flu epidemic was unusual in many ways:normally, mortality changed most for children

Another view of mortality by age


Great Britain

India

Niger

17th C. England

The HIV/AIDS epidemic is unusual in many ways: one complication is that it affects mainly adults


Great Britain

Botswana

Niger

17th C. England

The demographic transition involves both mortality and fertility

• Mortality rates fall due to better nutrition, public health conditions, medicines…

• What happens to fertility rates?–How high are the highest fertility rates?

biological maximum is around 12economic maximum is around 8-10

–How low are the lowest fertility rates? biological minimum is zeroreplacement fertility is around 2

Birth rates depend on both fertility (births/woman) and the number of women

© 2006 Population Reference Bureau

Worldwide

0.6

0.9

1.82.0 2.0

1.3

0

1

2

3

1950-1955 1970-1975 1990-1995 2010-2015 2030-2035 2045-2050

Bill

ion

s

0

1

2

3

4

5

6

Ch

ildre

n p

er

wo

man

Women 15 to 49 Average number of children per woman

Source: United Nations, World Population Prospects: The 2004 Revision (medium scenario), 2005.

Women of Childbearing Age and Fertility

Source: United Nations, World Population Prospects: The 2004 Revision (medium scenario), 2005 Reprinted from Population Reference Bureau, 2007 World Population Datasheet. (www.prb.org)

Fertility rates don’t always fall!Average number of children

per

woman

1950–1955

1955–1960

1960–1965

1965–1970

1970–1975

1975–1980

1980–1985

1985–1990

1990–1995

1995–2000

2000–2005

0

2

4

6

8

10

Source: United Nations, World Population Prospects: The 2004 Revision, 2005. Reprinted from Population Reference Bureau (www.prb.org), 2007.

Uganda

Kenya

Colombia

South Korea

Fertility Trends in Selected Developing Countries, 1950-2005

…and they vary in rich countries too!

Source: National statistical agencies.. Reprinted from Population Reference Bureau, 2007 World Population Datasheet. (www.prb.org)

Fertility Trends in Europe and the United States: 1980-2006

The fertility transition is usuallyfrom 6-8 to 1-3 births per woman

• What can explain this regularity? • Why do the poor have more kids than the rich?

– why might they choose higher fertility on purpose?poorer women may have fewer other optionstheir children may be more valuable to them

poorer children start work at a younger age …and may help parents in old age or sickness

where child mortality is high, parents need to have many children to have some survive

– availability and ease of contraception matters too!

One explaination for fertility declineis lower infant mortality


Fertility decline versus infant mortalityacross countries


Fertility decline vs. infant mortality over time


The demographic transition affects more than population growth

• How does transition affect the mix of people?–Death rates fall mainly for children–Fertility rates fall later and more slowly

so the burst of population growth

takes the form of more surviving children

Demographic transition and age structure:your textbook “population pyramid”

Demographic transition and age structure:the population pyramid for Nigeria

1980

Reprinted from www.census.gov/ipc/www/idb.


2000



2020

This helps explain your results from Exercise 1!


Demographic transition and age structure:population pyramids for Indonesia

1980


Indonesia has a much more “mature” population pyramid than Nigeria


2000




2020



Demographic transition and age structure:population pyramids for the United States

1980


The population “ages”, but there arecontinued echoes of the post-WWII baby boom


2000




2020



Demographic transition and the age structure of the population

• During the demographic transition, when death rates fall before and faster than birth rates, – at first kids are an increasing share of the

population, so the “dependency ratio” rises– then kids are a decreasing proportion of

people, and the share who are working rises– eventually share who are elderly rises, and

the proportion who are working falls again

Source: UN Population Division, World Population Prospects: The 2000 Revision (http://esa.un.org/unpp)

Past and Projected Child Dependency

Changing age structure has a big influence on the economy

0

10

20

30

40

50

60

70

80

90

100

1950

1960

1970

1980

1990

2000

2010

2020

2030

2040

2050

No.

of c

hild

ren

(0-1

4)pe

r 10

0 ad

ults

(15

-59)

E. Asia S. Asia Sub-Sah. Africa Whole World

• The demographic transition to higher and then lower population growth rates…– starts with a decline in child mortality

due historically to better nutrition and living conditions, and then to medical intervention

– is completed by a decline in fertility due mainly to increased child survival,

increased investment in child’s education, reduced need for child’s work, and increases in mother’s other opportunities

In conclusion...

…demography is very important!

– in Europe death rates fell slowly, in response to slow improvements in standard of living;

– in Africa, Asia and Latin America, death rates fell quickly with sudden availability of vaccines, antibiotics and disease control after WWII

– so today’s poor countries have had much faster pop. growth and worse dependency ratios than Europe or America ever did

agec 340 -- international economic development course slides for week 4 (feb. 2 & 4) population...

Documents

population growth rates

population economic

demographic transition

study of population

yr slide

mortality transition

fertility transition

people crude death rate