Resources 3.1 3.7 3.8

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Resources 3.1 3.7 3.8

  1. 1. DP Environmental systems and societiesTopic 3 Human population carrying capacity and resource use
  2. 2. World population3.1 POPULATIONDYNAMICS
  3. 3. Human population•
  4. 4. Implications of exponential (orgeometric) growth• Large amount of extra resources needed to feed, house and clothe• Argument that this is easier for LEDCs (less economically developed countries) than MEDCs (more economically developed countries)
  5. 5. Key values• Crude birth rate• Crude death rate• Fertility• Natural increase rate• Doubling time
  6. 6. Crude birth rate• Number of births per thousand people
  7. 7. Crude death rate • Number of deaths per thousand people
  8. 8. Fertility• Total fertility rate (TFR) is the average number of births per woman
  9. 9. Natural increase rate • CDR less CBR
  10. 10. Doubling time • The length of time required for a population to double its size
  11. 11. Transition • As countries develop from LEDC to MEDC, their demographics change
  12. 12. Population pyramids or Age/sex pyramidsWhat interpretations can be made here? High tax on young toHigh infant mortality Population maintained support older by immigration generation
  13. 13. Expanding Expanding Stationary Contracting Population declines
  14. 14. PredictionsFactors:• Migration• Economy• Status of women• Wealth• Religion• Social pressure• Pensions• Child benefits• Health care• Water• Sanitation• War• etc.
  15. 15. 3.7 LIMITS TO GROWTH
  16. 16. Carrying capacityThe maximum number of a species that can be sustainable supportedby a given environment (see Irish population crash)Malthusian theory (1978)• food supply the main limit to population growth – environmental limits• food supply will even decrease due to over-cultivation and erosionknown as ‘the law of diminishing returns’• The Club of Rome, an NGO, is neo-MalthusianBoserup’s theory (1965)• increased population would stimulate increased food productionthrough technology summarized as ‘necessity is the mother ofinvention’• desertification are evidences where overpopulation has not led totechnological innovation
  17. 17. Problems in predictinghuman population growth When one resource runs out humans change to another Human ingenuity Resources can be Technology imported in changes the resources (mining in available and space!?) amount required
  18. 18. 3.8 ENVIRONMENTALDEMANDS OF HUMANPOPULATIONS
  19. 19. Ecological footprintThe ecological footprint of a population is the area ofland that would be required to provide all thepopulation’s resources and assimilate all its wastesFor individuals:
  20. 20. Calculating the ecological footprintof a populationEcological footprint = (equation 1 + equation 2) x total population
  21. 21. Ecological footprint world map
  22. 22. Missing factors• Land or water required for aquatic and atmospheric resources• Land needed to assimilate wastes other than CO2• Land used to produce imported materials• Replacement of arable land through urbanization
  23. 23. MEDC vs LEDC
  24. 24. MEDC vs LEDC • Highly industrialized • Low forest growth (colder climate) • High forest growth • High meat diet (temperate climate) • High grain diet • Similar to US but with a low population
  25. 25. Population policies Lowering population growth through: 1. Economic development • MDG (millennium development goals) • Economists believe increased prosperity decreases the birth rate 2. Government policies • One child policy of China • Taxes and other incentives/disincentives 3. Education • Education about birth control • Education of women leading to independence is seen by some as the most effective way to reduce population

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