People and the Planet - Chapter One

How and why is population changing in different parts of the world?

  • Global Population Growth
  • National Variations in Population Change and Structure
  • Population Structure

How far can population change and migration be managed sustainably?

  • Managing Populations
  • Case Studies (very brief)
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  • Created by: Courtney
  • Created on: 05-05-11 10:35

Global Population Growth

During 2008 at least another 65 million people were added to the worlds population. This annual increase was less than during the 1980s and 1990s. Population growth rates have falledn from 2.1% per year to around 1.95%.

No matter where you are in the world, population change is produced by two proceses - natural change and migration change. The natural change dpends on the birth rate and the death rate. If there are more births than death, population will increase. If there are more deaths than births, the population will decrease. The infant mortality rate has also contributed to this lowering of the overall death rate.

Migration is the movement of people into and out of an area or country. If immigrants exceed emigrants there will be a gain in population. If the situation is reversed, ther ewill be a loss of population. However, any change in the total size of the global population results only from natural change. Migration simply helps change the distribution of that global population.

The more the birth rate exceeds the death rate, the hgher the rate of natural increase. The most important factor respnsible for the rising rate of population growth has been the fall in the death rate. A whole range of factors has contributed to the fall in mortality. They include: the development of modern medicines, the introduction of vaccination and immunisation programmes, better health care, more hygenic housing, cleaner drinking water and better sewage disposal and finally, a better diet.

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National Variations in Population Change and Struc

It has been observed that as countries develop, their birth and death rates change and as a result so tto does the rate of natural change. These changes underlie a generalisation known as the 'demograophic transistion model'. The model is a generalisation and not all countries follow the same pathway, also countries that do follow the pathway will do so at different speeds. The important factor is the speed of development.

The model suggests that the countries go through 5 differemt stages:

Stage One: High Fluctuating- A period of high birth and death rates, both of which fluctaute. Natural change hovers between increase and decrease. Reasons for the high birth rate include: little or no birth control, high infant mortality rate (which encourages couples to have more children), children are seen as a status symbol and an asset. The reasons for the high death rate include: high infant mortality, high incidence of disease, poor nutrition and famine, poor housing and hygiene, little or no healthcare.

Stage Two: Early Expanding - A period of high birth rates, but falling death rates. The population begins to increase rapidly. Reasons for the falling death rate include: lower infan mortality, improved healthcare and hygiene, better nutrition, safer water and better waste disposal.

Stage Three: Late Expanding - A period of falling birth and death rates. The rate of population growth slows down as the rate of natural increase lessens. Reasons for the falling birth rates include: widespread birth controlm oreference for smaller families, expense of bringing up childre, low infant mortalit rate.

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National Variations in Population Change and Struc

the rate of natural increase lessens. Reasons for the falling birth rates include: widespread birth controlm oreference for smaller families, expense of bringing up childre, low infant mortalit rate.

Stage Four: Low Fluctuating - A period of low birth and death rates. Natural change bovers ebtween decrease and increase. The population as a whole 'greys' as it becomes older. Death rate kept low by improving healthcare. Birth rate kept low by: effective birth control and more working women delaying the age at which they start having a family.

Stage Five: Decline - A period during which the death rate slightly exceeds the birth rate. The result is natural increase and a decline in population. The population becomes eve 'greyer'. Modern medecine is keeping elderly people alive longer. Fewer people are in the reproductive age which means a lower birth rate. This stage has only recently been reached - by some european countries.

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Population Structure

Two of the most important charachteristics of a population - age and gender - can be shown in a single diagram known as a population pyramid. The male population is shown on one side and the famle on the other side.

From a population pyramid we can understand that their shape is controlled by:

  • The birth rate - the higer it is, the broader the base of the pyramid.
  • The death rate - the lower it is, the taller the pyramid.
  • The balance betwee the two rates - whether births exceeds deaths or vice versa.

Age and gender are two physical qualites by which all of us can be classified. There are also two ascpects of population structure. They are the most important but there are others such as ethnicity, religion, occupation and class. Each of these is a different way of viewing and analysing the structure of a population.

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How far can population change and migration be man

One of the duties of the government is to monior what is happening to a country's population. The key to working this lies in the balance between the resources a country has and its population. If population out weighs resources hen all sortd of problems, known colletiley as overpopulation are likely to arise. Feeding all the people is one problem but so if unemploymet and housing. Is there enough?

On the other hand, but less commonly, the balance may tip in favour od resources. This means there will be underpopulation, Its problems and challenges are less demanding than those of underpopulation. Providing services and exploiting resources are two of the challenges.

An optimum population exists when resources and population are equally balanced. Achievning this sustainable situation is probably the main aim of most governments.

The target of most governments is the birth rate. If this is lowered then in time the population will decrease. It is usually lowered by encouranging birth control and making it expensive to have too many children. However, some religions are strongly against the birth control method. However, to increase the population, couples may be offered money or other benefits to have more children. Although they could also encourage migrants to come to thte country, especailly young adults who are likely to start a family.

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Case Studies

China's one child policy - in order to decrease the population.

makes it hard to look after children

Singapoures 'Have three or more' policy - in order to increase the population.

offers benefits such as flats etc to raise children

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