POPULATION GROWTH Overpopulation and Population Control

					          Overpopulation
       and Population Control




Miller, G. Tyler (2003) Environmental Science: working
with the Earth. Ninth edition. (Chapter 11)
      What Does Population Density Tell?


‘All too often, overpopulation is thought of simply as
   crowding: too many people in a given area, too high
   a population density.’

‘If brute density were the criterion (of overpopulation),
    one would have to conclude that “Africa is
    underpopulated”, because it has only 55 people per
    square mile, while Europe (excluding the USSR) has
    261 and Japan 857.”
         Distribution of Human Population




                                            World

Africa
         Effective Population Density
 If we exclude the desert or impenetrable forest of
  Africa, the more inhabitable portion is just over ½ of
  Africa’s area.
 Effective density = 117 per sq mile (≃ 1/5 of effective
  density in UK!)

 Even by 2020, Africa’s effective density ⋍ that of
  France (266 per sq mile), yet few people would
  consider France is overpopulated.
     Overpopulation Occurs When…


Overpopulation occurs when
the long-term carrying capacity of an area is
  being degraded by its current human
  occupants.
(**population size of an area relative to the
  area’s carrying capacity)
            Identifying Overpopulation
    According to World Health Organization (WHO), at present:
   1 billion people: living in poverty
   10 million people: die each year from malnutrition, starvation,
    and diseases from drinking contaminated water
   Premature deaths: 27,400 people per day
   Natural resources: under increasing pressure (depleting)

Main characteristics of overpopulation in animals:
 Mass suffering
 A high rate of premature death
 Deterioration of the environment
                Are we overpopulated?
                Ecological Footprints
Ecological footprint estimates the area of productive land
  required to
 produce the resources used
 give room for infrastructure
 assimilate the wastes produced (eg carbon dioxide
  emitted from burning fossil fuels)

at a specified material standard of living.

We have different ecological footprints
  We have different impacts on the Earth

A useful tool to measure and monitor sustainability.
      Global and Local Ecological Footprints
 1997 Ecological Footprint of global population: 2.85; 30%
  larger than the Earth’s biological productive capacity  rapid
  depletion of resources
 1997 Ecological Footprint of HK: 7.14 (ranked 13th out of 151
  countries and regions);
    If HK people continued to consume resources and emit
      carbon dioxide at the same rates
       would need 444 times the existing land area (or 170
      times the total area including marine waters) to sustain
      ourselves!
    If the whole world consumed resources and emitted carbon
      dioxide at rates similar to HK
       would need another two planets to support us!
   ** Stealing the Earth from our future
     generations!
                                       (Data: Living Planet Report 2000, WWF)
    Other Implications of Overpopulation


 Wealth Gap  poverty in developing countries
 Uneven distribution of food, medical care,
  education resources, family planning services
            Environmental Impact of Population

 Population size (P)   Affluence (A)        Technology (T)


                            No. of units      Environmental
       No. of                                 degradation &
                        of resources used
       People                               pollution per unit of
                            per person
                                              resource used
                                                    (environmental impact done by the
                                                    technologies used to supply the
                          Environmental             resources)
                            impact of
                           population

                       Impact (I)



                         I = PAT
How can we reduce the environmental impact (I)?
                Population Control
UN Conference on Population and Development,
 Cairo 1994 (15,000 leaders and representatives from
 179 countries):

 By 2054: world population stabilized at 7.8 billion
 By 2015: everyone on Earth should have
    Access to family planning
    Primary education for all children 6-11 yrs of age
    Increased involvement of men in child-rearing and
     family planning
                                       Population Projections
                                                      United Nations

                        11
                                                                       High TFR (2.5)
                        10
POPULATION (billions)




                         9                                             Medium TFR (2.0)
                         8
                        7                                              Low TFR (1.6)*
                         6
                         5
                         4                                             Current worldwide
                        3                                                  TFR = 2.8

                         1950   1970    1990   2010     2030     2050
                                           YEAR
                                                                               *Aim is
                                High              Low                         TFR of 1.6
                                        Medium
           Methods for Controlling Growth

 A government can alter size and growth rate of its
 population by changing any of the 3 basic demographic
 variables:
    Births
    Deaths
    Migrations

1. Most developed countries now have
   relatively low birth and death rates.
2. Most developing countries have
   relatively low death rates but high
   birth rates.
                          Crude Births and Crude Death Rates

                        Developed countries                  Developing countries
Rate per 1,000 people




                              Year                                    Year



                                          Rates of Natural Increase
               Controlling Migration
Only a few countries allow large annual immigration,
 e.g. Canada, Australia, USA.

Some migration is involuntary – involves refugees
  displaced by:
    War
    Natural disasters (earthquakes, flooding, drought)
    Environmental degradation (desertification,
     deforestation, resources shortage).
     Empowerment of Women


Women tend to have fewer and healthier children
 when:
 They have access to education and paid jobs
  outside the home
 They live in societies where they have rights
             Controlling Birth Rates
Focus of efforts to control population growth: decreasing
  birth rates

Two general approaches:
1. Economic Development may reduce the number of
   children a couple desires if
     They have increased access to education
     They have more economic security
     They do not need to consider children as old age
      security
2. Family Planning helps people regulate the number of
   children they want to have and when
             1. Economic Development
                               Demographers studied
                               western European countries
                               that industrialized in the 19th
                               Century.




Developed hypothesis of population change – demographic
transition.
   As countries become industrialized, first their death rates
   then their birth rates decline.
Encourage developing countries make the transition
 Help to reduce population growth
                                         The Demographic Transition

                                    Stage 1           Stage 2                Stage 3        Stage 4
                                 Pre-industrial     Transitional            Industrial   Post-industrial
                            40
Rates (per 1000 per year)




                                                               Birth rate
                            30


                            20
                                                  Death rate


                            10

                                      Low
                                  Growth Rates Increasing Growth Rates      Decreasing   ZPG   Negative
                             0
                                                           Time
                 The Demographic Transition
Four distinct stages:
 Pre-industrial stage: harsh living conditions
    High birth rates to counteract high infant mortalities
    Little population growth
 Transitional stage: industrialization begins
    Death rates drop
    Birth rates remain high
       Rapid population growth
 Industrial stage: industrialization widespread
    Birth rate drops
       Growth rate slows
 Post-industrial stage: relative high living standard
    Birth rates falls further, equaling death rate  ZPG;
    Then birth rate < death rate  Population decreases
                                          Developed and Developing Countries
                                                                                                 Population Reference Bureau
                                                                         40
Rate (per 1000 of population)



                                50            Birth Rate
                                                                                 Birth Rate

                                40
                                                                         30

                                30
                                                                         20      Death Rate

                                20            Death Rate

                                                                         10
                                10
                                        Mexico                                    Sweden
                                0                                         0
                                 1895       1920           1945   1970    1750        1800    1850      1900      1950


                                        In transitional stage                 In postindustrial stage

                            Most developing countries: transitional phase.
                            Most developed countries: industrial stage, a few in post-
                             industrial stage.
               2. Family Planning
Such programs provide educational and clinical services to
help couples (how many children to have and when to have
them), including:
  Birth control – contraception or
   sterilization
  Birth spacing
  Health care for pregnant
   women and infants
                                           Various forms of
                                            contraception
China has been more successful at
slowing population growth than
India.
                    Case Study: China
 1960s: Chinese government realized that without strict
  population control  mass starvation
 1970s: efforts made to slow population growth
 1979: one-child per family policy introduced
    Couples: urged to get married late and have only 1 child
    Married couples: free access to free sterilization,
     contraceptives, and abortion
    Married couples who pledge to have 1 child: extra food,
     larger pensions, better housing, free medical care, salary
     bonuses, free school tuition for the child, etc (couples will
     be deprived of all benefits if they break the pledge)
 1972 to 2001: TFR 5.7 to 1.8 children per woman


 Yet, compulsory birth control policy: Controversial!
          China’s Future Population

China has ~1/5 of world’s population
 11 million people added each year, but only has
    7% of world’s fresh water
    3% of world’s forests
    2% of world’s soils
 Greying population – who will take care of the
  elderly?
 Gender imbalance
    117 boys: 100 girls in 2000
      Men will outnumber women in China by 60
     million!

				
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