Transcript Overpopulation and development

Overpopulation and
development
Overpopulation
 The
number of people in a region is
greater than the ability of the land to
support them
 Carrying
capacity= no. of people a
region can support with its basic
resources
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Optimum Population – no of people in a region
with high standard of living given regions level of
development and natural resources at any time
Under population – no of people living in area
cannot exploit fully the natural resources
Inward migration improves SOL for all
Ireland 1997-2007 – labour shortages
Causes of overpopulation
1.
2.
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High birth rates: demand on basic
resources increase ie. The Sahel
Migration: people forced to leave
areas puts new areas under
pressure ie. Darfur in Sudan
Overuse of sources: resources that
the population depend on becoming
overused leading to overpopulation
ie. Cod banks in the north atlantic
Factors to increase carrying
capacity
Factors
How these factors work
1. Decreasing
population
Reduces demand for basic resources
2. Fertilisers
Increase food supply and feed more
people
3. New farming
methods
Feed more people
4. Irrigation
Raises crop yields, more water
5. Better crops/
animals
Feed more people
6. Land
reclamation
Provides new land for settlement and
farming
Factors to decrease carrying
capacity
Factors
How these factors work
1. Population
growth
Raises demand for basic resources
2. Soil erosion
Reduces food supply
3. Deforestation
Reduces fuel supply/ increases soil
erosion
4. Flooding
Destroys living space and farmland
5. Overgrazing/
over cropping
Damages soil and reduces food supply
6. Urbanisation
Raises demand for resources/ reduces
farmland
7. Climate change
Makes land areas uninhabitable
Case study: The Sahel
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An area stretching
across northern Africa
5,0000km long and
300km wide
a semiarid zone
extends from Senegal
(west) through
Mauritania, Mali,
Burkino Faso, Niger,
Northern Nigeria,
Sudan to Ethopia.
Case study
Focus on Sudan
 Same size as
France
 Barren land
 33% of population
live in 7% of land
 Capitol city
Khartoum
 Stage 2
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Factors contributing to
overpopulation and overuse of soils
1. Birth rate:
birth rate = 33 per thousand
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death rate = 10.28 per thousand
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Population 43million
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Infant mortality rates= 81 per thousand
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½ population under 18= HDR
Led to a number of problems:
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Overgrazing: status of cattle
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Deforestation: need of fuel, manure often used
(no natural fertilizer in the soil)
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over cultivation: use of cash crops to pay debt
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Factors contributing to
overpopulation and overuse of soils
2. Migration and conflict:
 Civil war and famine led to internal
migration
 Since 2003 Darfur has become a
human rights crisis region
 120,000+ fled to Chad or to area at
the east of Sudan
 Suffering brain drain
 Influx of 1milliion+ from Ethiopia
Factors contributing to
overpopulation and overuse of soils
3. Environmental degradation:
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Global warming: increased temp and evaporation
Droughts reduces food production
Rainfall levels decreased by 30% over 20 yrs
leading to drying of soil triggering erosion
Wells drying up and droughts 1968-73, 1983-5,
dug lower which lowers the water table
Desertification caused by deforestation and
drought cause the Sahara desert to spread
southward by 10km a year
Unsustainable Farming Methods
CAUSE
EFFECT
OVERGRAZING
Cattle
OVERCULTIVATION. FARMERS
ARE FORCED TO GROW CROPS
ON POOR LAND
THE
DEFORESTATION. TREES ARE
REMOVED FOR FUEL AND TO
CLEAR LAND FOR CROPS
REDUCED
exceed carrying capacity
Indication of wealth and importance
GRASS CANNOT REGROW
SOIL EROSION
DESERTIFICTION
CONTINUAL USE OF THE SOIL
LEADS TO LOSS OF SOIL
STRUCTURE. THE SOIL IS EASILY
BLOWN AWAY BY DESERT WINDS
SOIL EROSION
DESERTIFICATION
TRANSPIRATION OF
MOISTURE FROM PALNTS LEADS TO
LESS RAINFALL
ANIMAL MANURE USED AS FUEL
INSTEAD OF WOOD. NO LONGER
USED TO FERTILIZE THE GROUND
REDUCED CROP COVER
Effects of overpopulation
 Socio-economic
– Soil degradation
– Cash crops on valuable land
– Increasing population
– Farmers more sedentary
– Refugees not self reliant
 Environmental
– Change in rainfall patterns
– Conflict over water
OVERPOPULATION AND INCOME
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Areas with highest birth rates and highest levels
of population growth have the highest levels of
poverty
poorer countries have a higher birth rate
Children are seen as economic assets
In high income families – children an economic
liability - $50,000 to rear child 1-18yrs
Education of women central to decline in birth
rate
UN Development Programme:
1.3 billion live on less than .77 cent a day
800 million people do not get enough to eat
500 million are chronically malnourished
Impact of Income levels on
development
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UN development programme: 500 million +
malnourished
Poor people = larger families, economic asset
High population density not sole indicator of
poverty & population
High income families – children an economic
liability
Education of women central to decline in birth
rate
Income levels and development
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Kenya
Pop 39.8m
Density of 69km
poor, mainly rural
Stage 2
Population growing rapidly
(fertility rates high)
42% of pop= 1-14age group
Low incomes
Women low social status
Low quality education and
health services
Infrastructure poor
Foreign investment weak
Underemployment and
unemployment high
Low pop density but is
overpopulated
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South Korea
Pop 49m
Density of 487km
Successful economy, exports
orientated
Stage 4
Population growing slowly
Economy developed per
capita income improved
High quality education and
health
Densely populated
Modern lifestyle and a good
standard of living
Unemployment remains low
High pop density but it is not
overpopulated
Impact of technology on population:
medical technology
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World pop doubled in 40yrs
Medical research has developed vaccinations as
preventative measures
Improved access to family planning
Vaccinations have been developed to
cure/prevent infections ie. Measles etc
Infant mortality rates decreased
Some are cheap and administrated in primitive
conditions by use of syringe
Better education more women starting families
later
Rate of increase not as rapid as a result
Geneline therapy promised to eliminate fatal
Impact of technology on population:
agricultural technology
Increase in food supply leads to longer life expectancy
Advance
Results
1. Improved fertilisers
Increased yields
2. New strains of plants
Able to grow and thrive in
strained conditions
3. Chemicals
New pesticides and herbicides
allow food to thrive
4. Glasshouses
Able to grow plants in artificial
conditions all year round
5. Machinery
Harvesters, planters, pickers
gather more crops increasing
yields
6. Selective animal
breeding
7. Irrigation
Increased meat and milk yields
from each animal
Brings formerly dry land into
production
Ecological footprint and sustainability
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Ecological footprint Area of forrest land,
agricultural land, recreational space etc required
by a person to live
Several hectares per person in the developed
world V less than 1 hectare in developing world
2006 Switzerland 5.6 hectares
but China 1.8 hectares
Sustainability is based on the recognition that
when a resource is consumed faster that it is
produced or renewed the source runs out
Technology can make a positive difference
Developed world needs to change – buy food
locally, reduce air travel etc
GM foods & The Green
Revolution
 Increase
in food production,
technology & research, 1960’s
 Modified for desired traits e.g. Salt
tolerance
 Disadvantages:
– Expensive products and equipment
– Oil derived fertilisers- non renewable
resource
– Genetic diversity reduced
Population growth and developed
countries
Developed countries are in stage 4 and 5
 Agricultural and industrial revolution
caused economic growth in Europe
 Tax revenue allowed for continued
investment in health and education
 Increase in life expectancy and lower birth
rate
 Today high standards of living , aging
population and high GNP
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Population growth and developing
countries
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Stage 2 many countries experiencing high population
growth
30% under the age of 14yrs
Increase need of food, infrastructure, education and
services
Civil wars, corrupts leadership and MNC’s
Not experiencing economic development in the same way
that Europe did as due to unfair trading systems
Migration to shanty towns – cities pop can double in 15yrs
Low incomes cannot afford to invest in education and
health
Large families needed to provide economic security
Very young age dependency ratio
Population growth increase in rural-urban migration
Brain drain: leave to find well paid work else where
Loss slows down economic progress in country of origin
Over population impacts on society and
culture in Bangladesh
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Poor country
Primary economic activity: agriculture
Population: 158 million+
28% urban areas
1100 per km squared
Causes of over population
– Risk of flooding
 Low lying delta
 Annual monsoon season, typhoons
 1m of water floods 20% of Bangladesh land
 Sterilises agri land and contanimates water
 Infection: typhoid and cholera
 Social
Factors:
– Stage 3
– Birth Rates declining with family
planning
– 4 births per mother in 1990 but only 2.6
in 2011
– Muslim: Marry young, desire for sons
– Adult literacy rate only 47%
Effects of overpopulation
Bangladesh
 Migration
– Land scarce
– Rural to urban migration, lack skills, live
in shanty towns
 Overcrowding
– Both rural and urban areas
– Shanty towns= high mortality rates
– Domestic servants- remittance