Overpopulation and Population Control

1
Overpopulation and Population Control

• Miller, G. Tyler (2003) Environmental Science
  working with the Earth. Ninth edition. (Chapter
  11)

2
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.

3
Distribution of Human Population
World
Africa

4
Effective Population Density

• If we exclude the desert or impenetrable forest
  of Africa, the more inhabitable portion is just
  over ½ of Africas area.
• Effective density 117 per sq mile (? 1/5 of
  effective density in UK!)
• Even by 2020, Africas effective density ? that
  of France (266 per sq mile), yet few people would
  consider France is overpopulated.

5
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
  areas carrying capacity)

6
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?

7
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.

8
Global and Local Ecological Footprints

• 1997 Ecological Footprint of global population
  2.85 30 larger than the Earths 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)

9
Other Implications of Overpopulation

• Wealth Gap ? poverty in developing countries
• Uneven distribution of food, medical care,
  education resources, family planning services

10
Environmental Impact of Population
Affluence (A)
Technology (T)
Population size (P)
(environmental impact done by the technologies
used to supply the resources)
Impact (I)
I PAT
How can we reduce the environmental impact (I)?
11
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

12
Population Projections
High TFR (2.5)
Medium TFR (2.0)
Low TFR (1.6)
POPULATION (billions)
Current worldwide TFR 2.8
YEAR
Aim is TFR of 1.6
High
Low
Medium
13
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.

14
Crude Births and Crude Death Rates
15
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).

16
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

17
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

18
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

19
The Demographic Transition
Rates (per 1000 per year)
Low Growth Rates
ZPG
Negative
Decreasing
Increasing Growth Rates
20
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 lt death rate ? Population
  decreases

21
Developed and Developing Countries
Population Reference Bureau

• Most developing countries transitional phase.
• Most developed countries industrial stage, a few
  in post-industrial stage.

22
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.
23
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!

24
Chinas Future Population

• China has 1/5 of worlds population
• 11 million people added each year, but only has
• 7 of worlds fresh water
• 3 of worlds forests
• 2 of worlds 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!