Human Population
Worldwide population change
Worldwide population has grown steadily since the early nineteenth century, as illustrated by the following diagram.
Areas with the greatest increase are in:-
· Asia
· Africa
· Latin America
Areas with the slowest rates of increase are in:-
· Europe
· North America
· Australasia
Within regions population change is the result of variations in natural increase and migration.
Natural Increase is the difference between Birth Rate and Death Rate
Birth Rate is the number of live births per thousand of the population.
Death Rate is the number of deaths per thousand of the population.
Demographic Transition Model
The changes in these rates and the effect on population can be shown on the Demographic Transition Model (Population Cycle) :
This can be divided into four stages:
Stage 1 - High Stationary
Birth Rate and Death rate are both high. Population growth is slow and fluctuating.
Reasons
Birth Rate is high as a result of:
· Lack of family planning
· High Infant Mortality Rate
· Need for workers in agriculture
· Religious beliefs
Death Rate is high because of:
· High levels of disease
· Famine
· Lack of clean water and sanitation
· Lack of health care
· War
· Competition for food from predators such as rats
Typical of Britain in the 18th century and the Least Economically Developed Countries (LEDC's) today.
Stage 2 - Early Expanding
Birth Rate remains high. Death Rate is falling. Population begins to rise steadily.
Reasons
Death Rate is falling as a result of:
· Improved health care (e.g. Smallpox Vaccine)
· Improved Hygiene (Water for drinking boiled)
· Improved sanitation
· Improved food production and storage
· Improved transport for food
· Decreased Infant Mortality Rates
Typical of Britain in 19th century; Bangladesh; Nigeria
Stage 3 - Late Expanding
Birth Rate starts to fall. Death Rate continues to fall. Population rising.
Reasons:
· Family planning available
· Lower Infant Mortality Rate
· Increased mechanization reduces need for workers
· Increased standard of living
· Changing status of women
Typical of Britain in late 19th and early 20th century; China; Brazil
Stage 4 - Low Stationary
Birth Rate and Death Rate both low. Population steady.
Typical of USA; Sweden; Japan; Britain
The Infant Mortality Rate is the number of children who die before their first birthday.
These changes are reflected in the population structure.
Population structure
Population structure can be shown as a population pyramid:
Features of a population pyramid.
· Population is divided into 5 year age groups.
· Population is divided into males and females.
· The percentage of each age /sex group is given.
Distribution
Population distribution describes the way people are spread across the earth.
This distribution is:
· Uneven
· Subject to change
Why has the structure of some populations changed?
The change results from two processes:
· older people are living longer
· fewer babies are being born
Older people are living longer because of:
· developments in medical science
· improved health care provision
Fewer babies are being born because:
· more women go out to work
· educated women may choose to develop a career rather than raise a large family
· the age of marriage has increased
· contraceptives are more easily available
· there are changing lifestyles, where families prefer to have fewer children
· in the past children contributed to the family's income - nowadays they're more likely to be economic burdens
· better health care means that people don't have to have large families to ensure the survival of a few
These factors have led to a decrease in the EU fertility rate from 2.75 children to each woman in the appropriate age group in the mid-1960s, to a current rate of 1.43 children per female. To maintain a stable population, a level of 2.1 is required. All across Europe fertility rates, and therefore populations, are decreasing.
Impact of a changing population
We've learned that across Europe there has been a drop in fertility, leading to an ageing population. This can cause problems, and these problems can arise at both ends of the age structure.
The increased population of older people means that:
· there is an increased demand for health and social care
· it becomes increasingly difficult for governments to provide satisfactory pensions, which are ultimately funded by the working population
The reduced numbers of babies and children means that:
· there is less need for schools and school teachers
· industries which provide products for children - for example pram manufacturers - may suffer
· in the longer term, companies may have difficulty recruiting youthful workers
Possible solutions
These are some of the issues, but are there any solutions? The statement from the MSP that 'Scots should be paid to breed' suggests that the use of financial incentives is one possible solution. The Singapore government has launched a pro-natalist campaign, and hopes to increase the birth rate by:
· giving financial inducements for third children
· giving paid maternity leave
· providing state-funded child care centres
Whether these incentives would make any difference in Western Europe is debatable. The alternative option, tried in a number of countries experiencing a labour shortage, is to encourage immigration.
Human Population - new linkPopulation Growth - Chapter 41.5
Making Vaccines- animation