IGCSE地理 1.1 population dynamic, 1.2 migration

Parents often have many children to compensate of these expected deaths (most in LEDCs)。

1.1 Population dynamic

• Demographers: people who study human populations
• The rapid increase in the world’s population
  • *Faster rate of growth in least developed countries
  • 1800-1950, after World War II growth in rich country
  • 1960s, highest 2.4% annual (population explosion )
  • NOW, Rate of growth falling for four decades, 1.1%
    • Demographic momentum (number of people added each year) remains very high, because of huge number of woman in birth age
  • FUTURE, little or no growth in developed countries, much are from immigration
• Over population&under population
  • Carrying capacity: the largest population that the resources of a given environment can support.
    • Over-population: lead to a decrease in standard of living for the population as a whole.
    • Optimum population: the size of population that permits the full utilization of the natural resources of an area, giving maximum per people output and standard of living
    • Under-population: population is too small to develop its resources effectively
  • Effects of increasing population
    • Positive: allows a fuller exploitation of resource, cause living standards to rise
    • Negative: increase pressure on resources, cause living standard to decline
  • Facts that shows human population is against the limit of Earth’s resources
    • 1/4 of children have protein-energy malnutrition
    • The long-term trend for grain production per person is falling
    • 40% agricultural land is slightly degraded and 9% is highly degraded
    • Water scarcity occur in every continent, 40% people in the world
    • 1/4 of all fish stocks are overharvested
    • Global peak oil production will come as early as the next decade
  • Issues of over-population
    • Intense competition for land
    • Heavy traffic congestion
    • High house price
    • High environmental impact of economic activity
    • Pressure on eater resources
• The causes of a change in population size
  • A) Rate of natural change: the difference between the birth rate and the death rate. (Natural increase&natural decrease)
    • Death rate: number of deaths per thousand population in a year
    • Birth rate: number of births per thousand population in a year
  • B) net migration: the balance between immigration and emigration
    • Immigration rate: number of immigrants per thousand population entering a receiving country in a year
    • Emigration rate: number of emigrants per thousand is population leaving a source country in a year
  • #DTM model (demographic transition model)
    • Stage 1: high stationary
      • BR high, stationary
      • DR high, fluctuating (disease, war and famine)
      • Natural growth, slow
      • High infant mortality rate, low life expectancy
      • High young dependents
      • Pre-industrial, most people live in rural area, dependent on agriculture
    • Stage 2: early expanding
      • BR remains high (social norm governing fertility take time to change)
      • DR decrease (better nutrition, improved public health, clean water supply, efficient sewerage system, medical advances)
      • Rate of natural increase raise to a peak
      • Infant mortality rate fall, life expectancy increase
      • Young dependents increase
      • Rural-to-urban migration takes place
    • Stage 3: late expanding
      • BR decrease
      • DR remains low
      • Rate of natural increase slows down
      • Infant mortality rate decrease, life expectancy increase
      • Relatively young population structures (usually have lower death rates than nations in stage4 or stage5)
      • Urbanization generally slows
    • demographic dividend
    • Stage 4: low stationary
      • BR low (slightly higher than DR)
      • DR low
      • Natural increase low
      • BR fluctuating, due to changing economic conditions
      • DR rise slightly, due to average age increase
      • Life expectancy improve, age-specific mortality rate fall
    • Stage 5: natural decrease
      • BR low (below death rate)
      • DR low
      • Natural decrease (if without immigration)
      • Take place in a limited but increasing number of countries, mainly European
      • High old dependents
      • High urbanization level
• Contrasts in demographic transition
  • Details: difference from previous developing countries and present developing countries
    • BR in stage1-2 were generally higher
    • DR fell much more steeply
    • Greater population growth in stage2-3 due to larger base populations
    • Steeper fall in fertility rate in stage3
    • Much weaker relationship between population change and economic development
  • Reasons:
    • BIRTH: Factors affecting fertility
      • Fertility rate: the number of live birth per 1,000 women aged 15–49 in one year
      • Total fertility rate: the average number of children a woman has during her lifetime
      • A) Demographic:
        • Infant mortality rate: the number of deaths of children under 1 year of age per 1000 live birth per year
          • Parents often have many children to compensate of these expected deaths (most in LEDCs)
      • B) Social&cultural:
        • Low status of woman
          • Higher fertility
          • Without family planning
          • Woman produce as many children as possible
        • Female literacy (woman emancipation)
          • Lower fertility
          • Have knowledge of contraception
          • Greater social awareness
          • More opportunity of employment
          • Wider choice of action
        • Education
          • 1-extending education opportunities
          • 2-lower population growth
          • 3-increasing prosperity
        • Religion
          • Oppose artificial birth control
          • Be forbidden to abortion
      • C) Economic:
        • a) Higher fertility rate in less developed countries
          • Children are economic asset
          • Little support to the elders, need for support from children
        • b) Lower fertility rate in more developed countries
          • Cost of the child dependency years
          • People get marry later, shorter time for reproducing
        • Effects of economic growth
          • Greater spending on health, housing, nutrition and education
          • Lower mortality, reducing fertility rate
      • D) Political:
        • Population policy: government try to influence population size, growth, distribution or composition for economic and strategic reasons
          • Pro-natalist policy: to encourage more birth, stop population decline
          • Anti-natalist policy: to encourage fewer birth, reduce population growth
          • Encourage migration: to modify the distribution of the population
    • DEATH: Factors affecting mortality
      • Life expectancy at birth: average number of years a newborn infant can expect to live under current mortality levels
      • Social&economic factors causes high rates of infectious disease
        • Poverty
          • Live in overcrowded condition
          • Less of clean water, sewage system
        • Poor access to healthcare
          • Unable to get a treatment
        • Antibiotic resistance
          • Poor nutrition causes deficient immune system
        • Changing human migration patterns
        • New infectious agents
      • Solutions:
        • Public education
        • disinfect
      • #Mortality due to HIV/AIDS
        • Facts
          • Eastern and Southern Africa, 19 million people living with HIV, highest number of AIDS-related death
          • 2.1 million people become newly infected with HIV
          • From 2010 to 2015, number of people dying from AIDS in Middle East and North Africa increased by 22%
        • Causes
          • Poverty and social instability that result in family disruption
          • High levels of other sexually transmitted infections
          • The low status of woman
          • Sexual violence
          • High mobility, link ti migratory labour systems
          • Ineffective environment
        • Impact
          • Labour supply
            • Economic active population reduce as more people fall sick and unable to work
            • Severe impact on development
            • Threatened food security as there are fewer people able to farm
          • Dependency ratio
            • People contract HIV are mainly in the economic active population, increase death rate in this age group, increase dependency ratio
          • Family
            • Household dissolved
            • Impoverishing entire family, many children and old people have to take on the role of carers
            • Parents dead, cause large number of orphaned children, strain in governments
          • Education
            • With limited investment in education, people are unaware about how to avoid HIV/AIDS
            • Teachers who have AIDS are too ill to work
          • Poverty
            • AIDS impede development, increase the impact of poverty
            • Poverty worsens the AIDS situation, people can’t pay for treatments.
          • Infant and child mortality
            • AIDS can be passed from mother to child

1.2 Migration

• Migration: the movement of people across a specific boundary, to establish a new permanent place of residence
  • National & international
  • Voluntary & involuntary
• Push and pull factors
  • Push factor: negative conditions at the point of origin that encourage or force people to move
    • Poor employment opportunities
    • low income
    • House shortage
    • Social upheaval
    • No freedom of speech
    • Adverse climate
      • It is predicted that climate change will force mass migrations in the future
    • Natural disasters
  • Pull factor: positive conditions at the point of destination that encourage people to migrate
    • Good job prospects
    • High wage
    • Improved housing
    • Freedom of speech
    • High standard of living
    • Wide range of amenities
    • Attractive environment
• Voluntary and involuntary migrations
  • Voluntary migration: the individual has a free choice about whether to migrate or not
    • Higher salaries
    • More employment opportunities
    • Retirement to a warmer climate
  • Involuntary (forced) migration: people move against their will
    • Religious discriminations
    • political persecution (need for political asylum)
    • Famine (scarcity of food)
    • Natural disasters
    • War
      • Refugee: people who must leave their home area for their own safety or survival
• International and internal migrations
  • International migration
    • Migration of foreign labour, international student, high skilled workers has become increasingly temporary and circular in nature
    • While many traditional migration streams have remained strong, some new streams have developed
    • 48% are female migrants
    • Migrants move from developing to developed countries
    • Developed countries have reinforced controls, to response to security issues, also to combat illegal immigrants
    • Globalization brings benefits to both developed and developing countries
  • Internal migration
    • Rural-to-urban migration: most of the population movement within countries
    • Rural depopulation: an absolute decline in the population of an area, usually due to a high level of out-migration
    • 1) Urbanization
    • 2) Counterurbanization: the process of population decentralization as people move from large urban area to smaller urban settlements and rural areas
      • To seek a better quality of life by getting away from the problems of large cities
• Impacts of migration
  • Origin countries
    • positive
      • Remittance as a major source of income in some countries
        • Money sent back by migrants to their families in their home community
      • Ease the level of unemployment and underemployment
      • Reduce pressure on health, education services and on housing
      • Return migrants can bring new skills, ideas and money into a community
    • Negative
      • Loss of young adult workers who may have vital skills (the ‘brain-drain’ effect
      • An ageing population in communities with a large outflow young migrants
      • Agricultural output reducing if the labour force falls below a certain level
      • Migrants returned may question traditional values, causing divisions in the community
  • Destination countries
    • Positive
      • Increase the pool of available labour may reduce the cost of labour for businesses, help reduce inflation
      • Migrants may bring important skills to the destination
      • Increasing cultural diversity can enrich receiving communities
      • Young migrants can reduce the rate of population ageing
    • Negative
      • Migrants take jobs from people in the long-established population (cause unemployment to local people)
      • Increase pressure on housing stock and on service, such as health and education
      • Change in the ethnic balance of a country or region may cause tension
      • A large population can have a negative impact on the environment
  • Migrants
    • Positive
      • Higher wage than in the origin country
      • Wider choice of job opportunities
      • A greater opportunity to develop new skill
      • Have ability to support family members by remittances
      • Have the opportunity to learn a new language
    • Negative
      • The cost of migration can be high
      • Separate from family and friends in origin country
      • Hard to settling into a new culture (assimilation)
      • Can be exploited by unscrupulous employers (be screwed)
      • Especially illegal migrants, many migrants can involve hazardous journeys