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Population Pyramids

Population structure – number or % of males and females in different age groups within.

Demographic Dividend

  • Potential for rapid economic growth in a country as its dependency ratio drops. Normally in stages 2 and 3 of the DTM.
  • Death rate starts to decrease before birth rate i.e. people still have many children but more survive into adulthood, a bulge in young people.
  • When they reach working age, there is a large workforce and fewer dependant old/young.
  • Leads to economic growth such as working population pays taxes and can afford to spend more, boosting local economies.
  • TNCs attracted by large workforce, driving investment and employment.
  • To reach dividend, the country needs to first invest in education and job creation since unemployed and underemployed young adults count as dependant population.

 

International Migration

  • Refugees – forced to flee own country, unable to return due to fear of persecution and conflict such as over 1.8 million fled South Sudan amid violence and hunger.
  • Asylum seekers – fled country but not yet been accepted as a refugee. Can only get formal assistance and legal protection from country they seek sanctuary from once they are granted refugee status.
  • Economic migrants – people moving from one country to another for employment.
  • PUSH (why people want to leave).
  • Natural disasters.
  • Political instability.
  • Conflict/war.
  • Lack of employment.
  • Lack of food.
  • Economic uncertainty.
  • PUSH (why people are attracted to host).
  • Fewer extreme environmental events.
  • Better access to healthcare.
  • Better sources of education.
  • More job opportunities.
  • Better quality of life.
    • Other Factors Affecting Migration Patterns;
    • Government decisions about how many migrants are allowed in. Some have annual limits. When the A8 eastern European countries entered the EU, the UK was one of the few governments that allowed free movement through its borders.
    • Barriers to migration involve physical such as oceans, travel costs and human language.
    • Language/cultural ties such as Angolans and Brazilians both speak Portuguese.
    • Distance-decay – number of migrants tends to decrease as distance between country of origin and destination increases.

     

    • Migration Example – European Migrant Crisis 2015:
    • Over 600,000 migrants entered Europe from North Africa and the Middle East. Holding centres eventually reached full capacity in Sicily and Lesbos meaning squatter settlements arose in many parts of Europe.
    • Involved migrants dangerously crossing the sea in overcrowded unsanitary boats where many died en route. Also, many smuggled in cramped lorries and ships.
    • Implications for Country of Origin

 

Economic

  • Less unemployment.
  • Remittances sent from abroad.
  • Brain drain.
  • Service decline as demand decreases.

Political

  • May introduce pro-natal policies that could be rejected or praised.
  • Policies limiting freedom of movement.

Environmental

  • Reduced resource exploitation or intensive farming.

Health

Healthcare professionals leave in the brain drain.

Vulnerable ageing population places pressure on healthcare systems.

  • Lowered birth rates as people of childbearing age leave.
  • Population imbalance – higher ageing-population.
  • Loss of young working-age males.

Social

  • Reduced pressure of health and education, however funding may be cut as demand decreases.
  • Families can be split up/communities disbanded.

Destination (Host) Countries:

Economic

  • Migrants work for longer hours and cheaper labour. More inclined to fill jobs that native population won’t undertake.
  • Decreased dependency ratio.
  • Take more jobs than are available for native population.

Political

  • Pressures to control immigration.
  • Rise of anti-immigration parties and racist organisations.

Environmental

  • More housing and infrastructure required to sustain larger population.
  • Increased resource exploitation and pollution.

Health

  • Pressure on healthcare services.
  • Migrants can be healthcare professionals like doctors and nurses.
  • Social
    • Cultural diversity.
    • Social tensions between immigrants and local people.
    • Pressure on schools to make more places.
    • Segregation of migrants into certain areas which attract more migrants.

Population Ecology

  • Population ecology – how the dynamics of population interact with the environment.
  • Population growth dynamics – how and why population sizes/structures change overtime.
  • Limited by environmental factors: climate, soil, geology and topography and resources.
  • Balance between population growth and resource availability leads to three scenarios:

 

  • Optimum population – where the resources available can be developed efficiently to satisfy the needs of the population. Gives the highest economic return per person and therefore the highest standard of living. However, as technology develops, population can increase due to more resource availability – raised carrying capacity.
  • Overpopulation – population is too high for the resources available. Standard of living falls due to shortage in food, water, energy etc. Results in unemployment and out-migration.
  • Underpopulation – not enough people to utilise resources efficiently/to full potential so standard of living falls lower than it could be. Low unemployment rates and in-migration.

 

Population Ecology Key Terms

  • Carrying capacity – the maximum number of people that can be supported indefinitely long-term by the available resources in each environment.
  • Biotic potential – the natural reproductive potential of a species.
  • Environmental resistance – mortality rates are controlled by environmental factors preventing survival including famine and disease.
  • However, this is not as influential on humans as we have the capability to alter our environment to cater to our needs unlike many animals.
  • Density independent – environmental limiting factors that aren’t influenced by the population size and density such as natural disasters will decrease a population regardless of its size
  • Density dependant – limiting factors including food supply and disease will have more of an effect when population size and density are high.
    • Exponential growth – continually increasing population growth. Due to advances in technology making food production more efficient and vaccines/medicine reducing incidence rates of disease. As a species, we will have overcome limiting factors.
    • Logistic growth – as population size increases, the rate of increase will slow down. Predicted to be due to a rise in environmental resistance such as dwindling food and water sources.
    • Population growth will experience a plateau or equilibrium, maybe with some fluctuation above and below at carrying capacity.

     

    Ecological Footprint

    • Method of measuring environmental impact of human activity – calculates amount of productive land required to produce goods and services in demand.
    • Can be calculated on an individual scale, group scale or global scale.
    • HICs have bigger ecological footprint than LICs e.g. Zambia 1 gha vs UK 5 gha.
    • As ecological footprint increases, the carrying capacity decreases (more resources needed for each person, the fewer people our environment can support).
    • Current rate of consumption, our global population is using equivalent to 1.6 Earths i.e. it takes the Earth over a year 1/2 to regenerate resources being used in one year.
    • UN estimates if global population reaches 9.6 billion by 2050, we will be consuming three Earths’ worth of resources.

Positive Feedback

  • Change leads to processes amplifying original change.
  • Population growth increases demand for food > drives an increase in food production > more food availability allows population to increase further > further drives to improve yields and technology > leading to higher food availability etc.
  • An increased population results in more extraction of fossil fuels > more fuel supports the transportation of food to places experiencing shortage > decreases malnutrition > allows for further population growth.

 

Negative Feedback

  • Change leads to processes having an opposite effect to original change.
  • Growing population causes expansion and intensification of agriculture > leads to increased soil erosion > decreases yields because the soil is becoming less fertile > food production is not sufficient to support population > population declines.
  • Increased population leads to increased extraction and use of fossil fuels for energy > increased levels of greenhouse gas emissions create climate change > this can reduce rainfall and crop yields suffer > causes food shortage, reducing population.