Population issues in development economics

 

Population level, population growth.

 

Why should we be focusing on population issues?

 

1)  Do you have enough and will you have enough public goods such as security, roads, sanitation, clean water, health care, education,…..?

2)  Do you have enough and will you have enough jobs for people?

3)  Do you have enough and will you have enough food to feed people, and will you be able to improve nutrition?

4)  Is there a link between poverty and family size such that population growth is high because poverty is high?

5)  Will population growth become a problem in the context of current resource allocations – more people, fixed ‘pie’?

 

Population description:

 

Currently around 6.6 billion (Maddison).

Projection of maximum of 11 billion by 2200.

 

Over 90% of this projected population will live in what are currently defined as the countries in the developing world –though who knows what their status will be then.

 

Rapid increase in world population from 1950 to current times.

 

2000 years ago, around 250m people. 

1750, around 750 m. 

1950-1980 rapid growth. 

Still increasing.

 

Per year population growth estimates:

Up to 1650:  0.00002 (0.002%)

1650-1750: 0.003    (0.3%)

1850 -1900: 0.006   (0.6%)

1930-1950:  0.010  (1.0%)

1960-1980:  0.023  (2.3%)

 

Now down from high of 2.3% growth to around 1.3%

 

Calculate a doubling time.

Ln (2)

Rate

Years to double

.693

0.002%

34,657

.693

1.0%

69

.693

2.3%

30

 

Slightly different from the numbers in the book, but close enough.

 

Rapid decrease in mortality rates is main driving force behind these growth patterns.

 

 

 

Where are the poor:

 

Developing countries, as we have noted before.  Projections indicate this will if anything increase over time.

 

More than 75% of total world population currently is in developing countries.

 

How do we measure population change?

 

Rate of population growth for a given country.  % yearly net change in population size due to natural change and net international migration.

 

Natural change:  the difference between fertility and mortality.

 

Question – are all countries in the world currently experiencing positive population growth?

 

Crude Birthrate (a measure of fertility).  Number of births per year per 1000 individuals in the population.

 

What is the birthrate in developing countries? 

Something like 20 to 40.  In the developed countries it is more like 15.

 

Crude death rate.  Number of deaths per year per thousand individuals in the population.

 

Dropping from 28 to 15 in Central African countries from 1950 to present.

Alabama counties around 10 in 1994.

 

Annual growth rate:  Crude birth rate minus crude death rate

 

((#b-#d)/1000)

 

Expressed in percentage terms, 1.5% to 2.5% range for developing countries.  0.1% to 1.5% range for developed countries.

 

 

Crude Birth Rate/1000

Crude Death Rate/1000

Annual growth rate

Infant death rate/1000

SSA

41

15

2.6%

89

US and Canada

15

8

0.7%

7

World

23

9

1.4%

42

1999 WDI


Table 008. Vital Rates and Events

---------------- ---------- ---------- ---------------- --------------- -----------

                     Births     Deaths    Net number of Rate of natural           

Country or area/  per 1,000  per 1,000     migrants per        increase Growth rate

Year             population population 1,000 population       (percent)   (percent)

---------------- ---------- ---------- ---------------- --------------- -----------

 

SUB-SAHARAN AFRICA

 

1996                   41.8       15.7             -1.2            2.61        2.49

1997                   41.6       16.2             -0.9            2.54        2.45

1998                   41.3       15.8             -0.3            2.55        2.51

1999                   41.1       15.8             -0.4            2.53        2.49

2000                   40.9       15.7             -0.3            2.52        2.48

2001                   40.7       15.7              0.0            2.50        2.50

2002                   40.4       15.6             -0.0            2.48        2.48

2003                   40.1       15.6             -0.3            2.45        2.42

2004                   39.7       15.4             -0.3            2.43        2.40

2005                   39.3       15.1             -0.1            2.42        2.41

2006                   39.0       14.8             -0.1            2.41        2.40

2007                   38.5       14.5              0.0            2.41        2.41

2008                   38.1       14.1             -0.0            2.40        2.40

2009                   37.7       13.8             -0.4            2.39        2.34

2010                   37.2       13.5             -0.1            2.37        2.36

2011                   36.8       13.3             -0.1            2.36        2.34

2012                   36.4       13.0             -0.1            2.34        2.32

2013                   35.9       12.8             -0.1            2.31        2.30

2014                   35.5       12.6             -0.1            2.29        2.28

2015                   35.0       12.4             -0.1            2.26        2.25

2016                   34.6       12.2             -0.1            2.24        2.23

2017                   34.1       12.0             -0.1            2.22        2.21

2018                   33.7       11.8             -0.1            2.19        2.18

2019                   33.3       11.6             -0.1            2.17        2.16

2020                   32.9       11.5             -0.1            2.14        2.13

2021                   32.5       11.3             -0.1            2.12        2.11

2022                   32.2       11.1             -0.1            2.10        2.09

2023                   31.8       11.0             -0.1            2.08        2.07

2024                   31.4       10.8             -0.1            2.06        2.05

2025                   31.0       10.7             -0.1            2.04        2.03

2026                   30.7       10.5             -0.1            2.02        2.01

2027                   30.4       10.4             -0.1            2.00        2.00

2028                   30.1       10.2             -0.1            1.99        1.98

2029                   29.7       10.1             -0.1            1.97        1.96

2030                   29.4        9.9             -0.1            1.95        1.94

2031                   29.1        9.8             -0.1            1.93        1.92

2032                   28.8        9.7             -0.1            1.92        1.91

2033                   28.5        9.5             -0.1            1.90        1.89

2034                   28.2        9.4             -0.1            1.88        1.87

2035                   27.9        9.3             -0.1            1.86        1.85

2036                   27.6        9.2             -0.1            1.84        1.84

2037                   27.3        9.0             -0.1            1.83        1.82

2038                   27.0        8.9             -0.1            1.81        1.80

2039                   26.7        8.8             -0.1            1.79        1.78

2040                   26.4        8.7             -0.1            1.77        1.76

2041                   26.1        8.6             -0.1            1.75        1.74

2042                   25.8        8.5             -0.1            1.73        1.73

2043                   25.5        8.4             -0.1            1.71        1.71

2044                   25.2        8.3             -0.1            1.69        1.69

2045                   24.9        8.2             -0.1            1.67        1.67

2046                   24.7        8.1             -0.0            1.66        1.65

2047                   24.4        8.0             -0.0            1.64        1.64

2048                   24.1        7.9             -0.0            1.62        1.62

2049                   23.9        7.8             -0.0            1.60        1.60

2050                   23.6        7.8             -0.0            1.58        1.58

 

 

Total fertility rate:  the average number of children a woman would have in her life assuming that current age-specific birthrates remain constant throughout her childbearing years – 15-49 years of age.

 

High in Africa:  5.2.  Italy, Spain, Latvia 1.2.

 

Replacement rate is around 2.1 (mom, dad, and some mortality / infertility)

 

 

 

 

 

One other measure to consider is the life expectancy at birth.  The number of years a person born today is expected to live.  So not just birth, but how long each person born stays around.

Besides issue of population size and population growth, we also should note there are issues related to population structure.

 

Dependent children:   Individuals under 15 years old

Dependent adults:  People 65 or older

 

Dependency ratio:  Ratio of dependent people to working age adults (15-65)

 

Child / Youth dependent ratio.

 

Adult dependent ratio.

 

 

The child dependent ratio in developing countries is around 40%, while in developed countries it is around 20%.

 

The hidden momentum of population growth.  Population growth will continue even if the fertility rate declines substantially. 

 

 

The policy implemented has achieved a fertility rate of 2 for the youth generation as they pass from youth status in generation 1 to reproductive status in generation 2. 

 

The fertility rates for the reproductive group and the post reproductive group reflect the fertility rate that characterized the cohort in question during their childbearing years.

 

The starting size of the population is equal in all four scenarios, but how they got there (past fertility rates) differs.  All stabilize population level by generation three, but will stabilize at different levels.

 

 

 

Gen 1

Gen 2

Gen 3

Gen 4

youth fr=2

20

20

20

20

reproductive fr=2

20

20

20

20

post reprod. fr=2

20

20

20

20

 

 

 

 

 

Total population

120

120

120

120

 

 

 

Gen 1

Gen 2

Gen 3

Gen 4

youth fr=2

25

25

25

25

reproductive fr=2.4

21

25

25

25

post reprod. fr=3

14

21

25

25

 

 

 

 

 

Total population

120

142

150

150

 

 

 

Gen 1

Gen 2

Gen 3

Gen 4

youth fr=2

30

30

30

30

reproductive fr=3

20

30

30

30

post reprod. fr=4

10

20

30

30

 

 

 

 

 

Total population

120

160

180

180

 

 

 

Gen 1

Gen 2

Gen 3

Gen 4

youth fr=2

40

40

40

40

reproductive fr=5.3

15

40

40

40

post reprod. fr=6

5

15

40

40

 

 

 

 

 

Total population

120

190

240

240

 

Start with this one:  The five post reproductive had 6 kids each during their time so 30 total, 15 were female and these females (current reproductive) had a fertility rate of 5.3 so 80 kids total (79.5 rounded up), half female, so 40 youth.

 

For identical fertility rates in the youth cohort, the country with a larger cohort of future reproductive females will experience higher population growth.

 

Given a bottom heavy age structure, the number of parents is expected to increase as time goes by, so even if they give birth to children at a replacement rate of around 2, the population will still increase.

 

Time lag until demographic “bulge” passes through reproductive years.  Population structure indicates there is built in growth to the total population even if policies lead total fertility rates to replacement rates for the future reproductive cohort– stability is a generation off.

 

From

http://www.census.gov/ipc/www/idb/

Can be either population numbers per cohort or % of total population in the cohort on the x-axis.  Y axis is age cohort.  Left and right is male or female.
Population Pyramid Summary for Ghana

 

By way of contrast:

 

http://www.census.gov/cgi-bin/ipc/idbpyrs.pl?cty=US&out=d&ymax=250

The Demographic transition.

 

Three stages in the book, but seems like four to me:

 

I.                 High birth rate, high death rate.  Stable or slowly growing population.

II.             High birth rate, declining death rate.  Slowly leads to rapid growth in population.

III.         Declining birth rate, low death rate.  Rapid leads to slowly growing population.

IV.         Low birth rate, low death rate.  Stable or slowly growing population.

Show graph.

 

 

 

 

 

 

 

 

 

Can you get caught in stage II?

 

A race between income growth and population growth.  Per capita income reflects the outcome of this race.  If population growth is too rapid, it can outstrip the increase in total income, and growth in income is the underlying variable in the demographic transition. 

 

X-axis in demographic transition is time, but also income per capita implicitly.

 

A variant is that rapid population growth outstripping income leads to environmental damage that undermines the potential for future income growth.  Eat into natural capital.  More on this in environment development section.

 

Malthus-  fixed factor is land.  Diminishing marginal returns.  Eventually geometrically growing population outstrips arithmetically growing output.  Any surplus we have above subsistence we use up having more kids, eventually leading to long run subsistence trap.

 

Underestimates role of technological progress.  Recall Solow estimation results for TFP.

 

Note Boserup’s hypothesis that population pressure leads to technological innovation.

 

Also, assumption that income and population growth rate are positively correlated not well supported by the data (see figure 6.11 on page 282)

 

 

 

 

 

Demand for children models. 

 

A utility maximizing individual. 

Maximize utility of consumption subject to constraints. 

 

Children are a consumption good that give you happiness (no, you don’t really eat them). 

 

Demand for children who survive to adulthood.

 

Demand for an additional child for an individual (or a household) can be expressed as:

 

Demand (

household income,

net cost of raising a child reflecting the opportunity cost of raising children rather than other activities weighed against the expected future benefits of the child,

prices of other goods,

tastes for other goods relative to children,

probability existing children will survive to adulthood)

 

Predictions:

Higher household income, more children.  Children are a normal good.

(research on the question: are children an inferior good or a normal good – one study finds children are an inferior good when the wife has lower education, and a normal good when the wife has higher education Willis JPE 1973).

 

Higher net cost, less likely to have another child.  This includes opportunity cost recall.

 

Higher future benefits, more likely to have another child.

 

Higher prices other things, more likely to have another child.

 

Higher tastes for other goods, less likely to have another child.

 

Higher probability children will survive to adulthood, less likely to have another child.

 

Although we might think of such a perspective as whacky given the reality of fertility decisions, it turns out to be a pretty good model. 

 

Evidence from empirical studies suggests:

High female employment opportunities,

Greater female school attendance,

Lower child mortality rates (higher probability of child survival)

Formal social support systems for the elderly, lower fertility rates.

 

Note that income and opportunity cost are pulling in opposite directions as income increases if income is a function of time devoted to non-child raising activities.

 

Increase job opportunities, education, and health care for women as a way to reduce population growth. 

 

Note that while this seems somewhat nice and rather obvious, it is important as a response to the argument that such efforts will be self defeating, as households trapped in a set of values that places numbers of children above all other priorities will only use the improved social services to have more children.

 

Note also that family planning programs that do not address these underlying conditions will be limited in their impact.

 

Is population growth really a problem?

 

Some arguments for no, it is not.

 

Address development needs, and population growth will reduce as a result.  The population growth problem is really the context of poverty, poor health, poor education, and lack of social security that lead to population growth, not growth in and of itself. 

 

The distribution of the existing population is the issue, not the overall number.  People are clumped up in a few places that are clearly overstressed (mega cities for example), but there are vast underpopulated areas that could accommodate these people given correct policy and incentives.  More people is not a problem, it is where these people and the existing population are located that needs to be addressed.

 

The problem is the status of women, not the growth in population.  Focus on improving the status of women and population will sort itself out.

 

The population level in the developing world is only a problem given that the developed countries consume resources in a proportion far greater than their population share.  In turn, the poverty in the developing world provides conditions for rapid population growth.  If the developed countries would reduce their overconsumption, there would be more available to reduce poverty, thus addressing the conditions that lead to rapid population growth.

 

A deliberately contrived false issue.  Developed countries focus on population control since they realize that growing populations in the developing countries will eventually demand the unequal allocation of wealth and resources currently existing be redressed.  Racist attempt to limit the size and importance of non-white populations.

 

Could argue that population growth has benefits, not just costs. 

It creates consumers, laborers, and growth. 

Population pressure leads to innovation. 

Many areas of the world are currently underpopulated and underexploited.  There is evidence that past populations were in fact higher for some areas in Africa.   Slavery, diseases, warfare, governments.

 

Some arguments for yes, population growth is a problem.

 

Population bomb.  Population explosion. 

 

Per capita is GNP divided by population.  If the numerator grows slower than the denominator, then well being declines.

 

World food catastrophes and ecological disaster.  “Full House”.  “After decades of steady growth, the world’s food supply is no longer keep up with population increases” 

 

Population –poverty cycles.  Population growth that is too rapid exacerbates the problems of less developed countries.  Too many people in too short a time overwhelms the existing infrastructure.  Not enough water, schools, health centers, …

 

The consequence is declining living standards, leading to increases in population as family becomes the only means of security,…

 

International migration as an outcome with concerns raised about this issue in the recipient countries.

 

You need both development and family planning programs.  This is in some ways a means of filling the gap on social services directly to at least allow control over unwanted pregnancies.

 

Some kind of consensus.

 

1)  Population growth is not the primary cause of poor quality of life in developing countries.  It is the failure of other aspects of domestic and international development policy.

2)  Population and poverty has to be put in the context of the global distribution of resources. 

3)  Rapid population growth does intensify problems and make development harder (and more urgent).

 

Developing country policy options:

 

Persuasion

 

Establish family planning programs

 

Economic incentives and disincentives for having more children (limit maternity leave, money in bank for non-pregnant periods, tax breaks).

 

Coercion.  Forced sterilization.

 

Raise the social and economic status of women.

 

Developed countries:

 

Reconsider the relationship between population size and distribution of resources.  US has 4.6% of world’s population, uses 40% of annual world resource use.  Address environmental implications of consumption patterns in developed countries and their related impacts on prospects in developing countries.

 

Reconsider immigration policies.

 

Provide meaningful and effective development assistance.

 

Provide R and D for fertility control technology.

 

Provide meaningful and effective funding for family planning policies.