O Level Notes : Geography - Settlement And Population - The Demographic Transition Model

Population numbers and structures are not static; they change over time thus the population system is dynamic. The Demographic Transition Model (DTM) is a diagram which shows changes occurring in population with time.

The demographic transition model shows the relationship which exists between birth rate, death rates and total population. The DTM helps in determining the stage in which a country is found basing on its levels of birth and death rate in relation to total population based on studies done in the UK.

The Demographic Transition Model

The Demographic Transition Model has 4 stages which according to the theory are  followed  by  countries  with  demographic  trends  changes.  There  are suggestions that there is the fifth stage. 

Stage 1

Stage 1 is referred to as high and fluctuating because in this stage both birth and death rates are high at around 35% per 1000. Such a setup is typical of the individual society whose economies are substantially agro based. Such societies are also characterised by poverty, hunger and epidemics. Such societies are also not prepared in time they face natural disasters. Some of the African countries found in stage 1 are Somalia, Bangladesh and Ethiopia.

Switzerland and Germany are reported to have reached this stage. They thrive on imported labour since they have an ageing population.

Effects of population growth

Population growth is the change in population over time. There has been a rapid increase in the world population. Much of the growth has been experienced in developing countries where birth rates tend to be higher since people are bearing more children to meet their labour needs. 

There are several adverse effects of population growth. Some of these include: 

Strain on food resources

Most countries experiencing high levels of population growth are at a higher risk of failing to cater for their dietary needs of its population. An unchecked increase in population threatens food security so population increase results in a strain on food resources.  Many nations will then have to survive on food handouts from NGOs like World Vision and Plan International. 

Overburden on social service delivery

Population growth often leads to a challenge of overburdening social services delivery, like housing, transport and medication. An increase in population number translates to an increased demand of social services like housing, transport and medical drugs. More often, inadequate housing results in the proliferation of shanty towns, for example, Harare has several of these which include Hopley farm and Churu farm.

 High unemployment rates

Due to their lower levels of development, most countries economies are not able to factor industrial development which keeps pace with their increasing population growth often leading to high rates of unemployment. In turn, high rates of employment cause a high dependency load hence a country will continue to perpetuate a vicious cycle of poverty. 

Pressure on land

Population growth impacts on the resources. Whilst population numbers increase the land size does not expand to match the increasing population. Such a scenario normally degenerates into overpopulation. Overpopulation on the land leads to disappearance of forests and land degradation in the long run.

However, although an increase in population often results in several problems, it is also advantageous to a nation to some extent. Some of main benefits of population growth is that an increase in the number of people make labour supplies readily available and abundant.  When people seeking for employment are more, industrialists are placed in a better position on the negotiation table. 

An increase in the number of people in the country or area means increased demand for commodities. Thus when viewing it from an economical point of view, population growth promotes trade since there is a ready market for goods and services. 

Due to recent development in the transport sector, population growth in a country may be advantageous to surrounding nations since the world is now a global village. For example, South Africa's economy is flourishing because of the backup it is getting from its neighbours like Malawi and Zimbabwe whose nationals are thronging South Africa in search of employment opportunities and cross border traders. 

Population decline equally impacts on countries both positively and negatively. A multiplicity of factors often results in the reduction of a country's population over time. Chief among the causes are high death rates caused by pandemics, natural disasters and explicit population policies. Some of the countries which have now experienced population decline are Bulgaria, Alabama, Bosnia, Croatia, Hungary and Greece just to mention but a few. It is projected that between 2020 and 2025

Rate of population decline per country



Total population

Rate of population decline





















developing countries including Zimbabwe are still struggling to contain their blooming population numbers. Several measures can be put in place to curb

growth. Some of these measures include: 

Effective family planning methods.

Birth rates are the main feeder of people in the population system. All countries which aim to reduce population growth should embrace and foster effective family planning methods. In Zimbabwe, information with regards to family planning is delivered to people by the government through Zimbabwe National Family Planning council. Although the organisation is trying its level best to maintain population number low, its main challenge is that the Zimbabwe national policy is non explicit. In as much as it encourages couples to have smaller families, the policy is not quite clear on the number of children each family is supposed to have. To some couples, few implies 2 children to some 5 and to some 8 are few. 

Woman emancipation

If governments are really serious about reducing population growth they should consider emancipating their women. When most women in a nation are emancipated, marriages are delayed when women will be pursuing their academic and professional endeavours. Women emancipation reduces the fertility rates by delaying marriages and empowering women so that they will not become child bearing machines. 


A reduction in the population number goes hand in hand with the people's level of education. Effective use of contraceptive methods requires some degree of literacy among people. Moreso, the government through the health and childcare ministry should invest in education of the nation on the advantages of maintaining population numbers low and the ill of booming population numbers. Education should be much concentrated on the grass roots where many people still believe in having large families. Education should be done using both electronic and print media facilities compatible with different societies in the nation. Although many people would argue for a population decline, a fall in population number has several adverse consequences some of these includes:

 Labour deficiency

A decline in population negatively impacts on nations especially those whose level of automation and mechanisation are very low. In most countries labour is supplied by the economically active age group therefore a fall in population numbers does not spare this age group resulting in a labour deficiency in the industries.  A fall in labour supply simultaneously results in decreased industrial production hence loss of money to both the industrialist and the government. 

Underutilisation of resources

Several areas have adequate resources to fend for their present and future generation. A decrease  in  the  number  of  people  in  such  countries  causes underutilisation of resources. When a country's resources are underutilised the level of development of that country lags behind. Underutilisation of resources is often evidenced by dilapidated structures, closed industries and ghost settlement. 


Population decrease goes  hand in groove with ageing population. If a nation has most of it people in the old age group, it is bound to be strained economically because it invests a lot of its funds in old people's homes and the upkeep of the aged people.



However, it should be noted that in overpopulated areas population decline is of paramount importance. This is so because a fall in population numbers in some instances creates a state where resources available will be sufficient to meet the needs of its people. In other words, population decrease can help an area to archieve optimum population. 

Population decline

Population decline refers to a condition in which there is a reduction in the number of people leaving an area. Countries like Albania, Bosnia and Bulgaria are already experiencing a decline in population. 

Improving levels of mechanisation

Many families in developing countries are still pushing for large families to cater for labour on their agro based economies. An investment by the government in modern machinery can fill the gap for the need for labour hence couples can agree to bear less children thereby ensuring a reduction in population growth. 

Reducing infant mortality

Certain communities bear more children due to the prevalence of high infant mortality rates. Parents living in areas where infant mortality rates are high, tend to bear more children in the hope that if some die some will survive. The most unfortunate thing is that a few will die hence population growth is fuelled. Infant mortality rates can be curbed by improving health care delivery systems, improved access to medication and provision of balanced diets.