Transcript Population distribution and density

Population distribution and
density
Human elective
Population distribution
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People spread across the world
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Distribution is very uneven
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Places difficult to live include mountains
and deserts, places attractive to live
places with resources
Population density
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Average number of people living per sq km
Related to population and the land available
Calculated by dividing the population by the
land area
High population density: Java has a
population den. Of 5000 per sq km
Low population density: Amazon rainforest
has a pop. den. of 3 per sq km
Factors affecting population
distribution and density
Physical factors:
1)
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Climate:
where people live comfortably, crops can grow
successfully
90% of the world pop live in the northern hemisphere
temperate zone
Pop den. Highest in the region= long growing seasons
ie. Europe and North East USA
Factors affecting population
distribution and density
Physical factors:
2) Relief:
 Flat low-lying areas = high densisties
 80% of pop live in altitudes below
500m
 Mountainous regions have low pop den
 Building infrastructure easier in flat
lands, better communication networks
Factors affecting population
distribution and density
Physical factors:
3) Soils:
 Fertile soils attractive for crops (brown
earth soil)
 Mountains tend to have poor soils, thin
or infertile, discourages living conditions
Factors affecting population
distribution and density
Physical factors:
4) Drainage:
 Areas with rivers more densely populated
 Water for farming, industry, to live
 Provide fertile soils (alluvial soils)
 Transport (River Rhine)
 Egypt: 90% of people live within 6km of the
Nile
Factors affecting population
distribution and density
Physical factors:
5) Resources:
 Regions with mineral deposits attract
industries
 Leads to major settlements such as coal
mining in the Same Bemuse region
Factors affecting population
distribution and density
Human factors:
1)
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Government:
Regions with stable political systems have higher
pop den. ie. Europe since the 2nd world war
Offer peace and justice as well as services
Political conflict zones lead to refugees fleeing
lower the population
Government schemes ie. Sponsored resettlement
brings people to more sparely populated areas
Factors affecting population
distribution and density
Human factors:
2) socio-economic:
 Economic growth offers job opportunities
 Change can be seen in growth ie. Ireland
where people move from west-east
 Religion: Utah high pop den of Mormons
Factors affecting population
distribution and density
Human factors:
3) Historic:
 Conquest and colonisation ie.
Plantations
 Events such as the Famine (low pop
den)
Population growth
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Influenced by birth and death rates, migration
Birth rates: number of live births per thousand of a
population
Death rates: number of deaths per thousand of a
population
Natural increase: difference between birth and death
rates, when birth rates are higher than the death
rates
Natural decrease: when death rates are higher than
the birth rates
Factors influencing birth and
death rates
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2.
3.
4.
Education and status of women
(social)
Standard of living (economic)
Government policy (social)
Religion, society and customs
(cultural)
1. Education & status of women
(social factor)
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Education allows women to make personal
decisions about family size.
More knowledge of health care-healthier
children-lower child mortality-no need for
more children to support elderly-low birth
rate
Better job opportunities-less desire for big
family-low birth rate
Older when leave education-fewer fertile
years available-fewer children born
2) Standard of living
(economic factor)
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High standard of living=low birth rates and
death rates
Cost of raising a child in Ireland over 8000
per year for the 1st 8 years
Access to clean water and better healthcare
Less developed countries no government
support
Large families=economic advantage
High birth rates and death rates due to poor
health care and services
3) Government policy
(social factor)
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China one child policy (1974), importance of
boys in society
Romania (1960’s) abortion outlawed, childless
people over 25 had to pay extra tax (10-20%
of income), allowances for children increased
Russia birth rates low leading the
governement to pay families for children
(almost 7,000 for 2nd and 3rd child)
Paris Region – extra money for a third child,
long maternity leave etc.
4) Religion, society and
customs
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Catholic influences strong=birth rates
higher (South America) due to
opposition to contraception and
termination
Society place demands: India having
sons economic advantage (dowry)
Women encouraged to have more sons
to increase family wealth
5) Fertility rates
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Total fertility rate: average number of
babies born to women during their
reproductive years
Influenced by the previous four factors
To replace its population country needs
a TFR of 2.1 children per women
Several European countries below this,
Ireland currently at this
AIDS
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One of biggest threats to life
expectancy
In 2007 39,000,000 suffers worldwide
Anti-retroviral drugs prolong life
Drugs too expensive for many 3rd world
countries
World
Population
History
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Patterns in Population Growth
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Initial pop low so growth was low
Agriculture started 12,000ya in middle east, asia and
europe
Malthus believed natural disaster necessary to keep
pop down - Famines, diseases and war kept pop low
Prior to good transport accessibility to food was
limited which affect pop growth also
Persecution by local laws contirbuted to deaths of
high numbers
1750 world pop began to grow rapidly:
•Agricultural Revolution - New farming methods & improved
technology… crop rotation, better farm machinery, use of seed
drill, better animal breeds, all of these increased food production
•Industrial Revolution - Invention of steam engine….factories &
coalfields developed -- employment, improved income, new
housing and dev. of towns, absorbed the increasing working
population
•Medical Revolution - Improved hygiene & medicine, eliminated
diseases, longer & healthier life
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These aided the pop explosion over past 60 yrs
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Life expectancy from 40 in 1950 to 75 in 2010 and
expected to be 82 in 2050
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Stable pop worldwide means 2.1 children per family….
Europe as low as 1.56 but Latin America = 4; Africa = 6
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Industrialisation, increased income, medical & education
dev. led to lower death rate and higher pop.
Regional Growth patterns over time & space
1990… 1.2 billion in developed world & 4.1 billion in less dev.
Half worlds pop was in east & south Asia… China 1.2 billion &
India 960 million. Europe 15% America (N&S) 14% Africa
12%
By 2025 Africa's share of world pop will double, south Asia &
Latin America will remain constant & east Asia into relative
decline.
Developed world drop form 23% to 17% in terms of world pop.
Falling Pop numbers:
Western Europe…. EG Switzerland & Sweden will have zero
growth rates by 2010, North Am. By 2030 & China by 2070.
Problem: Shortage of skilled labour, science & technology
graduates & shortage of taxes to sustain pensions & services.
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Demographic Transition
Model
Countries go through predictable changes
as the country develops economically
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5 stages to pass through
The Population Cycle – Stages 1-5
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Stage 1: High birth rate, high death rate. Low population growth due
to famine, disease, and natural disasters. Underdeveloped region –
dependent on agriculture. E.g. Somalia (Europe 1700)
Stage 2: The economy improves. Money is spent on healthcare and
clean water. Birth rate stays high, death rate drops a dramtically.
Population increases. E.g Nigeria and Bangladesh (Europe 1800’s)
Stage 3: Social and economic development continues. People start
having less children as most children survive to adulthood, lower
infant mortality. Population increase slows but continuous increasing
e.g. China, Mexico (Europe early 20thC)
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Stage 4: Low birth rate and death rate. Small
population growth.The country is now wealthy.
Women have an improved standing in society. Family
planning is widespread. E.g. Ireland, Thailand
Stage 5: The death rate is higher than the birth rate.
People have very few children. The population starts
to decline. Population in decline Germany and Italy
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Ireland expected to reach this stage in 20yrs
Factors Affecting Population Change
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The Status of Women
When women are educated
and involved in careers outside
the home they have less
children.
This greatly reduces the
population growth of a
country.
3 Children Families
After 3 generations
there are 27 children
being born.
2 Children Families
After 3 generations
there are only 8
children being born.
Dependency ratio
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This is the ratio between the non-working population
( children under 15 and elderly dependents over 65)
and the workers ( the economically active adults 15
and 65).
To get the dependency ratio for a country we add the
number under 15 and the number over 65, divide this
into the 15 to 65 age and multiply by 100.
Ireland 2002.
Under 15 = 827,428
Over 65 = 436,001
Between 15 and 65 = 2,653,774
DR for Ireland 2002 = 0.48 ie 48 dependents per 100 workers or 1 per
2.1 workers.
Population pyramid
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Three types progressive, stationary,
regressive
Population pyramid
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Progressive: wide base narrow top
(stage 1-3)
Stationary: square shape (stage 4)
Regressive: wide top narrow base
(stage 5)
Population pyramid
Carefully study the population pyramids of Kenya and India. For
both countries
1.
Calculate the total percentage (male & female) aged between 0 and
14 years
2.
Calculate the total percentage ( m & f) aged 65+.
3.
From your calculations state which country has (a) the highest
percentage of children; (b) the highest percentage of old people.
4.
From your study of the population cycle, explain the reasons for the
%s in 3a and 3b.
5.
Which of these countries could best afford free (a) primary education;
(b) secondary education and (c) third level. Explain each of your
answers.
6.
Which pyramid shape indicates (a) an industrially emergent country;
(b) a newly industrialized country? Explain.
Population pyramid
Case study: China
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The one child policy
1949-1976: population grew by several
hundred million
Average fertility: 6 children per mother
Pursued vigorously in urban areas: one child
allowed
Rural areas second allowed if first is a girl
Fines and penalties apply to those who don’t
comply
China problems associated to
the one child policy
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Gender bias
Resulted in imbalance in the sexes of babies
Ratio of 106.7boys: 100 girls cenus fig.
believed to be as high as 117:100
Need for agricultural labour
Pride in sons (tradition) some families
consider it a dishonour not to have a male
heir
China problems associated to
the one child policy
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Female abortion
Some couples have ultrasounds to identify
the sex of the baby (rural areas in the 2nd
child)
Led to widespread abortion of female foetus
1995 law passed banning abortion based on
gender, reported that despite this female
abortion and infanticide continue
95.7% of foetus aborted are female
China problems associated to
the one child policy
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Non registered births
Birth of females are sometimes not
registered leading to females living in
illegal limbo
90% children in orphanages are
abandoned girls
Results of one child policy
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Transition from high birth rate to low
birth rate
Moved from stage 2 to stage 4
Population still growing due to vast
amount of young married couples
(9million + annually)
Case study: Ireland
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Changes in density and distribution
Pre famine(1845-1848)agricultural rural
economy(pop. 8million +)(113km sq)
Post famine: emigration and death
reduced pop.
Early 20th century move of people
eastwards urban areas (GDR)
Today 66% of Irish live in urban areas
Case study: Ireland
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Population density and distribution
Lowest in west, midlands & Islands
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Some fertile lands have low density also as
settlement retricted
Highest density in coastal lowlands and
river valleys e.g Blackwater
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Well drained, fertile land and sea ports at
river mouths
Change over time:
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Post famine emigration continued,
Reached there lowest levels in 1960
(2.6 million) (39km sq)
Economic growth and in migration in
1960’s
Lemass Era (economic policies), MNC,
jobs, inwards migration, EEC 1973
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First pop growth in 120 yrs between
1971 and 1981
1980’s Recession & Emigration, 200,000
people emigrated during 80’s
1990’s Celtic Tiger, inward migration,
urbanisation due to concentration of
jobs in these areas
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66% of population today urbanised
Largest increase in East
Dublin, Louth Kildare, Wicklow up by
40%
Recession again in recent times so
emigration returned
Despite this pop expected to reach 5m
by 2015
Case study: Ireland
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Changes in population structure
Population aging (greying)rapidly
Present: over 65s =11% of population
Under 15’s down 10% since 70’s
2020= 14% of population over 65
2050= 29% of population over 65
Birth rate halved since 1980’s at 4
Economically active group (15-64yrs) up from
58% to 68% in 45yrs
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Dependency Ratio highest in 1966 at
74% is now at 46%
Predicted to rise again as pop ages
Consequences:
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Pensions, Nursing Homes, greater tax
burden
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TFR is 1.98 - maintenance is 2.1
Life expectancy since 1926
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Men – 57.4 – 76.8
Women 57.9 – 81.6
Advances in Health Care, Dr Noel
Browne eradicated TB
Sean Lemass
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Taosieach 1959-1966
“A rising tide lifts all boats”
1st programme for economic expansion
T.K Whitaker
Moved away from protectionist policies
£220m
Free Trade – 1961 failed attempt to join
EEC
Free education 1969
Case study: France
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Distribution
France population of 62.1million
50% population occupy over 10% of
the population
1930’s: urbanisation increased
2007: 77% of population living in urban
areas
Case study: France
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Areas of densest population
Paris area & lower part of the Seine
river(11m, 20% of pop)
The Lyon area
The Rhone valley
The Mediterranean coast
The Loire, Garronne and Rhine valleys
Brittany coast
Industrial area in Lorraine
Case study: France
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Places less densely populated
Great forests
Eastern part of the Paris basin
The Ardennes
Mountainous zones, the alps
Massif central
The Pyrenees
Corsica
Case study: France
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Population growth in France
18th century France saw a fall in death rate
Rapid population growth in 2nd half of 19th &
20th C
World War population growth moderate
Post war population growth: rose by 23million
to 62.1million
Death rate: stable at less than 10 per
thousand
Birth rate: Highest TFR in Europe at 8.65 per
thousand in 2011