Demographic Transition

The theory of the demographic transition share from a report simple to know that the space variations of mortality and birthrate are due to differences in demographic trends. The diagram of the demographic transition is a space-time model making it possible to describe the passage of a population having the birth rates and mortality raised with a population having rates of birthrate and weak mortality. The basic assumption of the theory of the demographic transtion is that all the populations of the world will evolve/move in the same way, with shifts of calendar in this evolution. This model was built by the demographers according to their observations and their analyzes on the evolution of the populations of the European countries and North-Americans in order to explain the passage of a mode of strong birthrate and mortality with a mode of weak birthrate and mortality. It is what interested in particular Adolphe Landry in France, taken again by Notestein in the United States at the beginning of the XX century. The model of the demographic transition is used for UNO to conduct its forecasts of population.

Four times

Traditional demographic mode (pre-transition)

The situation old (or traditional) is a situation of balance, characterized by a strong birth rate and a strong death rate, which thus causes a Natural increase weak. This phase is punctuated many peaks of mortality which had with wars, epidemics or of the famines. Strong birth rate compensates for at the same time these peaks of mortality and strong infantile death rate.

First phase of transition

Death rate strongly falls (progress medical, food, industrialization in the case of rich countries…) while the birthrate even remains strong increases. The natural increase is thus strong, which means rapid growth of the population.

Second phase of transition

Mortality continues to drop but more slowly and the birthrate is also put it to decrease. The maximum of the natural increase is reached at the beginning of this second phase. Then the birthrate more strongly drops and there is thus a deceleration of the rate/rhythm of Increase in population.

Modern demographic mode (post-transition)

One observes here birth rates and of mortality low. Mortality is about equal one year to the other and the regulation of the population is done from now on by the birthrate which knows fluctuations (during the traditional mode it was mortality which had this regulating role). Some times, the natural rate of increase can become negative, which then involves the problem of the ageing of the population, and later, a reduction in this one. One finds this case in Belgium, where the natural rate of increase is negative. Indeed, we currently witness an ageing of the population. It is more widespread nowadays.

Examples of transitions

The first countries to have known the demographic transition are the European countries. The duration of the transition is variable according to the countries. For example, the transition lasted one century and half in Sweden or England whereas the South Korea carried it out in 50 years. It is estimated that the majority of the countries of Europe, more particularly the Germany and the Italy, will know an extreme form of this phenomenon, where ageing will be accompanied by a reduction in the population.

Critics of the model

The French model

The observation of the French demographic transition must make doubt universality of the traditional diagram. Indeed, in France one observes (in 1750) and throughout the transition a fall joint and simultaneous from birth rates and of mortality what prevents France from making true demographic great strides at the time of this transition.

Open/closed system

The stages of the demographic transition are placed on the assumption of a closed system, i.e. where one neglects the international migrations to base oneself only on the entries and exits " naturelles" however the populations are open systems with an internal regulation (birthrate and mortality) and an external regulation (migrations). The latter has consequences on the volume of the population and that in a direct way (arrived - departure) is indirect (fruitfulness different from the foreign populations…).

Emigration and duration of the demographic transition

There would be a relationship between possibilié to emigrate and the duration of the demographic transition: indeed, the great European emigration of the 20th century to the maximum phase of increase in the demographic transition and thus isn't the relative length of the demographic transition corresponds related to this possibility of emigrating? With this question, one can risk an assumption based on the simple good sense: When the increase in a population is maximum, there is generally a danger of imbalance between the number of men and the number, means of existence (harvests to be divided of available employment,…. ). This déséquilbre is source of impoverishment. It follows a necessary emigration from there (it is the case of famished Ireland of the 19th century towards the United States, or of Italy according to the second world war towards Belgium). However they are mainly the young people who emigrate. Their departure results in to make fall the number of the births in their country of origin. Birth rates and death rates thus meet more quickly because of this emigration. The reasoning is opposite for the host country: the contribution of young immigrants maintains an high level of birthrate and consequently prolongs the demographic transition. One could state the following law: “The waves of immigration result in to reduce the number of years of the demographic phase of transition for the starting country and to lengthen it for the host country. ” This is not - let us recall it - that an assumption (Marc Moisse). This assumption contradicts the opinion of another writer. Contrary, one observes a fast demographic transition in the Third World countries, where one has increasingly strong restrictions of emigration towards the countries of North.

Birthrate and mortality

The demographic transition is focused only on the birthrate and mortality but there exist other indicators and in particular the age structure, which influences the birthrate and mortality. Independently of the birthrate and mortality, a demographic system can so maintain to its age structure policies of emigration or of immigration intervene like factor of regulation. Conversely, a stability of birth rates and mortality can in particular in the case of be accompanied by modifications of the age structure ageing of a post-transitional population.

Another criticism, generalizing the European evolution or of country like Iran or Brazil, stresses that birth rate at the end of the transition, far from ideally stabilizing itself approximately on the level of death rate, would continue its fall, causing a demographic decline preceded then still accompanied by ageing by the populations.

Diversity of the cultures

The interpretation of the demographic transition is eminently political and ideological: for some, she denies the diversity of the people and the cultures and claims to give an account of the one of their major and complex dimension - reproduction - using a diagram of doctrinaire approach. It is not indeed shown that the African and European people have the same demographic reactions vis-a-vis the same event. Thus, progress of medicine makes fall infantile death rate. The demographic history of the European countries shows that this fall was accompanied a few decades after a voluntary reduction by the births. However, in Africa, the transition is much slower. The demographic transition is also question of mentality and culture.

See too

External bonds

Increase in population
demographic Decline
Democratic transition, in policy.
the Rural migration, an example of transition

Sources

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