1.trends in world population
TRANSCRIPT
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Syllabus:
Population Geography the changing nature, rate and distribution of
the worlds population
spatial patterns of fertility and mortality types, volumes and directions of population
movements such as rural-urban migration,labour migration and refugee migration
issues arising from the changing size anddistribution of population includingenvironmental, economic and social impacts.
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Trends in World Population
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Global population growth
At present, the world's population isgrowing fast - though this has notalways been the case.
Until the 1800s the world's populationgrew steadily but slowly for thousandsof years.
In 1820 the world's population reachedone billion.
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Global population growth
150 years later, in the early 1970s, theworld's population reached three billion.
In 1999, less than 30 years later, thepopulation doubled to six billion.
The global rate of population growth isnow very fast (rising by about one billionevery 15 years).
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Global population growth
The graph shows this pattern of accelerating growth:
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Causes and rates of change
The population of any place changes over time.There are three main causes of populationchange:
Births - usually measured using the birth rate
(number of live births per 1000 of thepopulation)
Deaths - usually measured using the deathrate (number of deaths per 1000 of the
population) Migration - the movement of people in and out
of an area
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Rate of change
Births and deaths are natural causes ofpopulation change. The difference betweenthe birth rate and the death rate of a
country or place is called the naturalincrease, and you calculate the naturalincrease by subtracting the death rate per1000 population from the birth rate per 1000
population:
natural increase = birth rate - death rate.
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Patterns of population growth
Rates of population growth vary acrossthe world. Although the world's totalpopulation is rising rapidly, not all
countries are experiencing this growth.In the UK, for example, populationgrowth is slowing, while in Germany thepopulation has started to decline.MEDCs have low population-growthrates, with both low death rates and lowbirth rates.
http://www.bbc.co.uk/schools/gcsebitesize/geography/population/popchangestructurerev4.shtmlhttp://www.bbc.co.uk/schools/gcsebitesize/geography/population/popchangestructurerev4.shtmlhttp://www.bbc.co.uk/schools/gcsebitesize/geography/population/popchangestructurerev4.shtml -
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Patterns of population growth
LEDCs on the other hand have highpopulation-growth rates. Both birthrates and death rates in LEDCpopulations tend to be high. As LEDCsdevelop, however, improving healthcareleads to death rates falling - while birth
rates remain high. It is easy to see howthis leads to even higher population-growth rates.
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The table shows comparative birth rates, death ratesand population-growth rates in some LEDC and MEDC
countries:
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Population growth in LEDCs
Most LEDCs are experiencing rapidpopulation growth. Most LEDCs are instage two or three of the demographictransition model. This means that theyhave falling death rates, due toimproving health care and greater
access to modern medicine, while birthrates remain high.
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Stage 1 Stage 2 Stage 3 Stage 4
Naturalincrease
Birth rate
Death rate
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Population growth in LEDCs
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Shanghai
Shanghai is growing at an extraordinary rate.Officially the population has been growing at 29.4
people per hour. But its not through birth thatthe population is growing, its migration. China isexperiencing massive urbanisation - the process of
people moving to cities.
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Population change in MEDCs
Most MEDCs are experiencing slow rates ofpopulation growth. Some are actuallyexperiencing population decline.
Most MEDCs are in stage four of thedemographic transition model. Thosecountries with a declining population could besaid to be entering stage five. This means
that the birth rate in their country has fallenbelow the death rate. Most MEDCs have avery low rate of natural increase.
Population chan e in MEDCs
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Population change in MEDCs
Birth rates in MEDCs are falling as womenchoose to have smaller families later in life.
Contraception is easily available and wellunderstood. This helps women to plan theirfamilies and to have a career too
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An ageing population:
As people live longer the structure of apopulation changes.
Many MEDCs are now experiencing a
significant increase in the numbers of elderlypeople as a proportion of the population aswhole.
As birth rates fall and people have smaller
families, the number of young dependants isfalling and the number of elderly dependantsis rising.
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An ageing population:
In the near future this will mean that thereare fewer people of working age to supportthe elderly population.
To try to balance out an ageing population,some countries adopt a pro-natalist policy -that is, they encourage people to have morechildren by offering them benefits, such as
better access to childcare and betterconditions for maternity leave.
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