The Human Population: Dimensions

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The Human Population Dimensions

• Chapter 5

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Human Population Expansion

• Population increased slowly up until the 1800s
• The increase was slow with periodic setbacks

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• Approximately 1830 1 billion
• 1930 2 billion
• 1960 3 billion
• 1975 4 billion
• 1987 5 billion
• 1999 6 billion
• Current growth rate of 77 million people per year

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Pop estimates

• 2013 7 billion
• 2028 8 billion
• 2052 9 billion
• Leveling off at around 10 billion by the end of
  the 22nd century

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Reasons for the Patterns of Growth

• The slow and fluctuating growth prior to 1800s
• Prevalence of diseases such a smallpox,
  diphtheria, measles, and scarlet fever
• Particularly hard on infants and children
• Not uncommon for a woman who had 7 to 8 live
  births to have only 1 or 2 children reach
  adulthood
• All large epidemics eliminated adults

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Prior 1800s

• Human population dynamic balance
• High reproductive rates but high mortality
• What caused the change?

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Breakthroughs

• Discovered that diseases were caused by
  infectious agents viruses, bacteria, and
  parasites
• And these where transmitted via water, food,
  insects, and rodents
• Soon vaccinations were developed for different
  diseases

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In addition

• Discovery of penicillin, better sanitation and
  nutrition brought about spectacular reductions in
  mortality, especially among infants and children,
  while birthrates remain high

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Declines

• During the 1960s, the world population growth
  rate peaked at 2.1 percent per year, after having
  risen steadily for decades.
• Then it began a steady decline
• The declines are primarily a consequence of the
  decline in the world total fertility rate the
  average number of babies born to a woman over her
  lifetime

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• In the 1960s the total fertility rate was an
  average of 5.0 children per woman
• It has declined to the present value of 2.8
  children per woman

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UN Projections

• Global human population will reach 8.9 billion by
  2050
• But will increase
• Leveling off at around 10 billion well in the
  22nd century
• Based on medium scenario fertility rate
  assumptions

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Crucial

• The assumption of declining fertility rates is
  crucial
• If the current fertility rates remain unchanged,
  the 2050 population will be 12.8 billion

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The Question

• If the numbers do not level off how many more
  people can the Earth sustain

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• To answer this question we must take a look at
  the Different Worlds
• Three main economic categories
• High income, highly developed, industrialized
  countries (developed countries)
• Middle income, moderately devloped countries
• Low-income, developing countries

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Disparities

• The highly developed countries make up just 16
  of the world population
• Yet control 81 of the worlds wealth
• The low-income developing countries make up 41
  of the worlds population
• Yet control only 3.4 of the worlds gross
  national income
• A difference in per capita income of 62 to 1

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HPI

• United Nations Development Program (UNDP)
• Devised the Human Poverty Index (HPI)
• Based on life expectancy and living standards
• Shows that that there are poor people in every
  country (relative term) unable to afford
  adequate food, shelter, or clothing
• 10 to 15 poor in developed
• 45 in developing

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• 98 of world population growth is occurring in
  the developing countries

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Fertility

• Total fertility rate the average number of
  children each woman in a population has over her
  lifetime
• Replacement level fertility the rate that
  will just replace the population of parents
• Developing countries tend to have a higher rate

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• Should population increase in developing
  countries be a concern?

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• Should we be more concerned with a population
  increase in the devloped or developing country?

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Different Populations, Different Problems

• IPAT formula human pressure on the enviornment
  is a factor of therre things
• Population
• Affluence
• Technology
• I P X A X T

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• Based on this the affluent lifestyle that comes
  with living in an industrialized country
• A small population can have a very large impact
  on the environment

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• It is estimated that because of differences in
  consumption, the average American places at least
  20 times the demand on Earths resources
• The US with 5 of the worlds population, is
  currently responsible for over 24 of the total
  global emissions of carbon dioxide

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Enter Stewardship

• The environmental impacts of affluent lifestyles
  may be moderated to a large extent by practicing
  environmental stewardship
• Attention to wildlife conservation
• Pollution control
• Energy conservation and efficiency
• recycling

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• For sustainability all three areas must be
  addressed
• Population must be stabilized
• Consumption must decrease
• Stewardship action must increase

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The United States

• Leading the world in the consumption of many
  resources
• Lead in per capita consumption of many items,
  such as meat (more than 3x global average)
• Lead the world in paper consumption
• Enormous ecological footprint

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The Good

• We can afford to clean the water
• We can afford to us gas and electric instead of
  firewood
• We can afford conservation and management
• We can afford better agriculture practices
• We can afford pollution control

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The Bad

• We lead the world in the production of many
  pollutants
• Exploiting of fisheries
• Clear-cutting forests for fax paper
• Oil spills
• Exotic wood for furnishings
• Demand for metals

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The Ugly

• We can obtain resources from more distant
  locations
• We can also transfer wastes to more distant
  locations so we dont see or feel the impact
• Affluent isolates unaware of environmental
  stresses they cause

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Dynamics of Population Growth

• Population Profile a bar graph showing number
  or portion of people at each age for a given
  population
• The collecting, compiling, and resenting
  information about populations is called
  demography
• Population profile can be used as a planning tool
  for future demands of goods and services

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Future Populations

• Current population growth in a country is
  calculated from three vital statistics births,
  deaths, and migration.
• In 2000, in the US about 40 of the population
  increase was due to immigration and 60 to
  natural increase
• Demographers use this information to make
  projections

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Population Projections in Developed Countries

• For the next 25 years, Italys population will be
  graying
• What problems would this cause?
• What can they do about it?

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Population Projections for Developing Countries

• Fertility rates in developing countries are
  generally declining, but they are still well
  above replacement level
• Because of the higher past fertility rates, the
  population profiles of developing countries have
  a pyramidal shape. the rises adults produce
  even more offspring
• What does this mean in terms of needed resources?
  

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Population Momentum

• Countries with a pyramid-shaped population
  profile, such as Iraq, will continue to grow
  50-60 years, even after the total fertility rate
  is reduced to the replacement level.

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Demographic Transition

• The basic premise of the demographic transition
  is that there is a causal link between
  modernization and a decline in birth and death
  rates as a population becomes more modern there
  is a shift in birthrates to replacement or lower
  levels

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So should we worry

• This does not happen over night
• The most populous developing countries are still
  very far behind economically
• Consumption-oriented lifestyles will continue to
  cause environmental stress