3.2.4.4 Population change
INPUTS PROCESSES OUTPUTS
+ Births - Deaths
Natural change
Total population
+ Immigrants Net migration
- Emigrants/ out-migrants
Figure 1 Systems diagram showing the two components of population change.
Natural change and migration change are different and distinctive but not necessarily mutually
exclusive and will affect each other.
For example, many international migrants are of reproductive age, consequently an increase of
immigrants into a population will increase the child-bearing potential of that population, leading to
an increase in birth rate. There will also now be a smaller proportion of elderly in the population so
the movement of younger immigrants into a country will also reduce the death rate. If birth rates or
death rates (or both) are changed by a migration event, the migration will have had an impact on
natural change.
Natural population change
Country Birth Death rate Natural Infant Fertility Net
rate (per 1000) increase mortality rate production
(per (%) rate (per rate
1000) 1000)
Mali 45.53 13.22 3.231 104.34 6.16 2.5
Nigeria 38.03 13.16 2.487 74.09 5.25 2.1
India 19.89 7.35 1.254 43.19 2.51 1.1
South Korea 8.26 6.63 0.163 3.93 1.25 0.6
Japan 8.07 9.35 -0.128 2.13 1.40 0.6
The vital rates of natural population change are birth rate, death rate, infant mortality rate
and replacement rate. When birth rate exceeds death rate, there is a natural increase, but
when death rate exceeds birth rate, there is a natural decrease. All of the countries in the
,table are experiencing a natural increase, apart from Japan. This may be because Japan has
an ageing population, hence its death rate is higher. For the rest of the countries, there is a
natural increase – perhaps they have more youthful populations. The majority of these are
LICs, meaning women tend to have more children than in developed countries to ensure
that enough children survive into adulthood – Mali is an LIC and has the highest rate of
natural increase. South Korea is the most developed out of the countries experiencing a
natural increase, and this is reflected in the low value of 1.63% for its population change.
This is further illustrated by the fertility rate, as women in Mali are expected to have on
average 6.16 children in their lifetime, whereas women in South Korea are expected to have
only 1.25.
Mali also has the highest infant mortality rate, and Japan has the lowest. Infant mortality
rate is useful, as it gives an indication of the healthcare and wealth available in a country;
Mali is quite a poor country, whereas Japan is much wealthier. This is the general trend –
infant mortality rates tend to be higher in LDEs where child mortality rates are also high.
This links to the birth rate and natural increase.
Net production rate is a measure of the average number of daughters produced by a
woman in her reproductive lifetime. India, Mali and Nigeria all have net production rates
above 1, (1.1, 2.1, and 2.5, respectively) meaning the population in these countries will have
more females alive in the next generation than at present. However, South Korea and Japan
both have a net production rate of 0.6, meaning these populations will have less females in
the next generation than at present. These countries are more developed than the other
three.
Which is more useful? Replacement levels or net reproduction rates?
Net reproduction rate is more useful than replacement level. The current replacement level
is calculated to be 2.1, but there is actually very little evidence that says 2.1 is the optimum
fertility rate. Rather, there are many countries in the world where the rate of replacement is
greater than 2.1, which is a direct consequence of higher levels of mortality and skewed sex
ratios at birth, resulting from sharp gender inequalities. Also, replacement level calculations
assume that migration is zero, when this is typically not the case – there are always people
moving in and out of a country, and this will contribute to the population change. However,
although the rates used in the net reproduction rate calculation are those observed over a
given year for the whole female population (composed of several generations) and
therefore do not represent the rates for an actual generation of women, the fertility and
mortality of the mother's generation before the end of the childbearing age is taken into
account in the calculation of the net reproduction rate. Therefore, it is quite useful.
N.B. natural increase is important, as it indicates not only how a population is changing, but
the speed at which that change is occurring. The greater the difference between the birth
rate and death rate, the faster the rate of natural increase and thus the steeper the curve in
the growth of total population.
, Infant mortality rates
The number of children dying before their first birthday forms part of the death rate
statistics but is considered to be a particularly important measure of mortality because:
- It is age specific as it relates to one particular group. This group is vulnerable but
arguably is the group that society should be taking most care of.
- It gives an indication of the level of healthcare available, particularly maternity and
post-natal care, as well as the prevalence of, and ability to, combat diseases.
- It gives an indication of the wealth of the country. Higher income countries will be
able to afford the healthcare, medicines, healthy diet and clean water that will keep
infants alive.
- It will have an impact on fertility rate. Families in areas with high infant and child
mortality will have little choice but to have more children to ensure that some
survive into adulthood.
Cultural controls
Birth rates and fertility rates vary considerably on a global scale and are influenced by a
number of cultural controls (which are particularly important in determining fertility rates
and thus population growth) as well as other socio-economic and political factors.
Social factors:
- Healthcare and medical technology
- Education
- Status of women
- Culture and religious beliefs
- Age and gender structure of population
Economic factors:
- Economic conditions
- Affluence
Political factors:
- Population policies
- Political stability
Decisions about family size are influenced by socio-economic and sometimes political
factors, which will have long-term effects on culture. China’s infamous one child policy has
arguably dictated that Chinese culture accepts one child as being the social ‘norm’. As China
relaxed this policy a counter-culture of wealthy Chinese choosing to have more than one
child has developed. However many parents would still only have one child due to
economic, rather than cultural, reasons. A number of cultural controls will set the tone of
future population growth.
INPUTS PROCESSES OUTPUTS
+ Births - Deaths
Natural change
Total population
+ Immigrants Net migration
- Emigrants/ out-migrants
Figure 1 Systems diagram showing the two components of population change.
Natural change and migration change are different and distinctive but not necessarily mutually
exclusive and will affect each other.
For example, many international migrants are of reproductive age, consequently an increase of
immigrants into a population will increase the child-bearing potential of that population, leading to
an increase in birth rate. There will also now be a smaller proportion of elderly in the population so
the movement of younger immigrants into a country will also reduce the death rate. If birth rates or
death rates (or both) are changed by a migration event, the migration will have had an impact on
natural change.
Natural population change
Country Birth Death rate Natural Infant Fertility Net
rate (per 1000) increase mortality rate production
(per (%) rate (per rate
1000) 1000)
Mali 45.53 13.22 3.231 104.34 6.16 2.5
Nigeria 38.03 13.16 2.487 74.09 5.25 2.1
India 19.89 7.35 1.254 43.19 2.51 1.1
South Korea 8.26 6.63 0.163 3.93 1.25 0.6
Japan 8.07 9.35 -0.128 2.13 1.40 0.6
The vital rates of natural population change are birth rate, death rate, infant mortality rate
and replacement rate. When birth rate exceeds death rate, there is a natural increase, but
when death rate exceeds birth rate, there is a natural decrease. All of the countries in the
,table are experiencing a natural increase, apart from Japan. This may be because Japan has
an ageing population, hence its death rate is higher. For the rest of the countries, there is a
natural increase – perhaps they have more youthful populations. The majority of these are
LICs, meaning women tend to have more children than in developed countries to ensure
that enough children survive into adulthood – Mali is an LIC and has the highest rate of
natural increase. South Korea is the most developed out of the countries experiencing a
natural increase, and this is reflected in the low value of 1.63% for its population change.
This is further illustrated by the fertility rate, as women in Mali are expected to have on
average 6.16 children in their lifetime, whereas women in South Korea are expected to have
only 1.25.
Mali also has the highest infant mortality rate, and Japan has the lowest. Infant mortality
rate is useful, as it gives an indication of the healthcare and wealth available in a country;
Mali is quite a poor country, whereas Japan is much wealthier. This is the general trend –
infant mortality rates tend to be higher in LDEs where child mortality rates are also high.
This links to the birth rate and natural increase.
Net production rate is a measure of the average number of daughters produced by a
woman in her reproductive lifetime. India, Mali and Nigeria all have net production rates
above 1, (1.1, 2.1, and 2.5, respectively) meaning the population in these countries will have
more females alive in the next generation than at present. However, South Korea and Japan
both have a net production rate of 0.6, meaning these populations will have less females in
the next generation than at present. These countries are more developed than the other
three.
Which is more useful? Replacement levels or net reproduction rates?
Net reproduction rate is more useful than replacement level. The current replacement level
is calculated to be 2.1, but there is actually very little evidence that says 2.1 is the optimum
fertility rate. Rather, there are many countries in the world where the rate of replacement is
greater than 2.1, which is a direct consequence of higher levels of mortality and skewed sex
ratios at birth, resulting from sharp gender inequalities. Also, replacement level calculations
assume that migration is zero, when this is typically not the case – there are always people
moving in and out of a country, and this will contribute to the population change. However,
although the rates used in the net reproduction rate calculation are those observed over a
given year for the whole female population (composed of several generations) and
therefore do not represent the rates for an actual generation of women, the fertility and
mortality of the mother's generation before the end of the childbearing age is taken into
account in the calculation of the net reproduction rate. Therefore, it is quite useful.
N.B. natural increase is important, as it indicates not only how a population is changing, but
the speed at which that change is occurring. The greater the difference between the birth
rate and death rate, the faster the rate of natural increase and thus the steeper the curve in
the growth of total population.
, Infant mortality rates
The number of children dying before their first birthday forms part of the death rate
statistics but is considered to be a particularly important measure of mortality because:
- It is age specific as it relates to one particular group. This group is vulnerable but
arguably is the group that society should be taking most care of.
- It gives an indication of the level of healthcare available, particularly maternity and
post-natal care, as well as the prevalence of, and ability to, combat diseases.
- It gives an indication of the wealth of the country. Higher income countries will be
able to afford the healthcare, medicines, healthy diet and clean water that will keep
infants alive.
- It will have an impact on fertility rate. Families in areas with high infant and child
mortality will have little choice but to have more children to ensure that some
survive into adulthood.
Cultural controls
Birth rates and fertility rates vary considerably on a global scale and are influenced by a
number of cultural controls (which are particularly important in determining fertility rates
and thus population growth) as well as other socio-economic and political factors.
Social factors:
- Healthcare and medical technology
- Education
- Status of women
- Culture and religious beliefs
- Age and gender structure of population
Economic factors:
- Economic conditions
- Affluence
Political factors:
- Population policies
- Political stability
Decisions about family size are influenced by socio-economic and sometimes political
factors, which will have long-term effects on culture. China’s infamous one child policy has
arguably dictated that Chinese culture accepts one child as being the social ‘norm’. As China
relaxed this policy a counter-culture of wealthy Chinese choosing to have more than one
child has developed. However many parents would still only have one child due to
economic, rather than cultural, reasons. A number of cultural controls will set the tone of
future population growth.
