Chapter One

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Chapter One

• Humans, Geology, and the Environment

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What is Environmental Geology?

• Environmental Geology is the branch of geology
  which deals with the relationship between humans
  and their geologic environment.
• It is concerned with geologic processes that not
  only make human life possible but that also may
  threaten life.

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Environmental Geology uses many branches of
traditional geology, some of which include

• Mineralogy Petrology (minerals and rocks)
• Sedimentology (origin and interpretation of
  sediments)
• Structural Geology (how rocks deform)
• Geomorphology (Landforms)
• Geophysics and Geochemistry (physics and
  chemistry of the earth)
• Hydrology (study of water)
• Engineering Geology (building of structures on
  land)

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Environmental Geology applies the science of
geology to problems arising from the complex
interactions of the earths spheres.

• Atmosphere.
• The gaseous envelope/blanket of air that
  envelops, shields, and insulates the earth.
• 78 nitrogen, 21 oxygen, 1 Argon, 0.03 Carbon
  Dioxide, trace elements and water vapor.
• Sustains life on earth, protects from intense
  heat, plays an integral role in weather, and
  interacts with the hydrosphere.

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Environmental Geology applies the science of
geology to problems arising from the complex
interactions of the earths spheres.

• Hydrosphere.
• Waters of the earth including rivers, lakes,
  ocean, ice, groundwater.
• Earths oceans cover 71 of the earths surface,
  accounting for 97 of the earths total water.
  3 is found in lakes, streams, ground, biomass,
  atmosphere, ice.
• Hydrosphere plays an important role in shaping
  the earth through weathering, erosion.

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Environmental Geology applies the science of
geology to problems arising from the complex
interactions of the earths spheres.

• Lithosphere (or Geosphere).
• Solid, inorganic portion of the Earth composed of
  rocks and regolith (broken fragments and
  unconsolidated particles overlying bedrock).
• Includes rocks, soils and minerals.
• Biosphere.
• All living (and once living) components of the
  earth.

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How do we study Environmental Geology?

• Geologic maps
• Shows distribution and spatial relations of rocks
  at the surface (from rock outcrops) and the
  subsurface (from boreholes).

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How do we study Environmental Geology?

• Multipurpose Maps
• Show areas of unstable ground, locations of
  faults, areas of high flood potential, the depth
  to groundwater, mineral resources, etc.
• Used in land-use planning by planners and public
  officials
• Case Histories
• Study case histories of geologic events to make
  advances in knowledge.

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Population Dynamics - The study of how
populations grow.

• In 1900, the population of the earth was
  estimated at 1.6 billion. By 2000 this figure
  reached 6 billion.

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Too Many People!
Thomas Malthus (1812) An Essay on the
Principle of Population

• Populations grow geometrically (or
  exponentially) while supporting resources grow
  linearly.
• Population, if not purposefully checked, would
  outpace resources and lead to unplanned positive
  checks that would return population to
  sustainable levels.

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Carrying Capacity

• Linear growth - increases that occur in nearly
  equal increments.
• Geometric or exponential growth - increases that
  occur in increments that become larger with time,
  producing a J-shaped growth curve.

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Carrying Capacity

• Carrying capacity is the number of creatures a
  given tract of land can adequately support with
  food, water, and other necessities of life.

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Carrying Capacity

• As world population increases exponentially,

natural resources are rapidly being depleted.
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Population Growth Rate (PGR)

• Determined by subtracting a populations death
  rate from its birthrate, or
• PGR BR - DR.
• Death rates and Birth rates are expressed as
  deaths and live births per 1,000 people per year,
  respectively.

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Population Growth Rate (PGR)

• Example
• Birth rate 20 per 1000
• Death rate 10 per 1000
• Then, Growth rate 20 minus 10 10 per 1000, or
  1
• To calculate percent growth rate
• part over the whole x 100,
• in our example 10/1000 x 100 1

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Population Doubling Time (PDT)

• Time for a population to double
• Approximated by the rule of 70 where
• PDT 70/growth rate
• In our example, at 1 growth rate, PDT 70/1
  70 years
• at 2 growth rate, PDT 70/2 35 years
• at 3 growth rate, PDT 70/3 23.3 years...

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Population Doubling Time (PDT)
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Quiz

• 1. If growth rate 10 (or 10 per 1000 people),
  find PDT.
• growth rate 10/1000 100 1
• PDT 70/1
• PDT 70 years
• 2. If growth rate 20, find PDT.
• growth rate 20/1000 100 2
• PDT 70/2
• PDT 35 years

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Quiz

• 3. If PDT 17.5 years, find the growth rate.
• Remember PDT 70/GR, so GR 70/PDT
• GR 70/17.5
• 4 Growth Rate
• Remember, Growth Rate GR/1000 x 100, so GR
  GR/0.1
• GR 4/0.1
• Growth Rate of 40 per 1000 people.

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Average Annual Population Growth Rate (in
percent)
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Growth Rates and Doubling Times

• World - 1.7, 40 years
• Africa - 3, 23 years
• Latin America - 1.9, 37 years
• Asia - 1.8, 38 years
• North America - .7, 100 years

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Regional population patternsPopulation density
Consortium for International Earth Science
Information Network.
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Population Density and Growth Rate
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Global Population Growth and the Annual Growth
Rate for 1950 to 2000
Although the world growth rate has decreased, the
number of people added each year continues to
grow larger.
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United Nations Population Division 2002
Estimates
World population projections for 2050 range from
a low 9-10 billion to a high of 15 billion people.
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China "one-child-per-couple" policy since 1979

• Rewards for having only one child grants,
  additional maternity leave, increased land
  allocations. Children get preferential treatment
  in education, housing, and employment.
• Couples punished for refusing to terminate
  unapproved pregnancies, for giving birth when
  under the legal marriage age, and having an
  approved second child too soon.
• Penalties include fines, loss of land grants,
  food, loans, farming supplies, benefits, jobs and
  discharge from the Communist Party.
• In many provinces sterilization is required after
  the couple has had two children.

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Chinas Population Policy
Children per woman 1970 5.01 1995
1.84 Population still growing! Population in
2000 1.3 billion Projected for 2025 1.5
billion
Use of abortion Forcible abortions and
sterilization Infanticide
Criticisms
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World Population Growth, Resources, and the
Environment.

• Increased atmospheric CO2 concentration by 13
  from 1940.
• Decreased the protective stratospheric ozone
  layer by 2
• About 20 of bird species have become extinct in
  the past 200 years, almost all of them because of
  human activity
• Man uses more than half of the accessible surface
  fresh water
• Transformed or degraded 39-50
• of the Earth's land surface.
• Over 50 of terrestrial nitrogen fixation
• is caused by human activity
• On many islands, more than half of plant
• species have been introduced by man
• On continental areas, man has introduced
• 20 or more of the plant species present

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Overpopulation Scenario OneThe Sky is Falling

• The carrying capacity of the earth has either
  been reached or is fast approaching.
• The earth becomes uninhabitable as resources
  dwindle, sea level rises due to global warming
  and inundates coastal cities, and hazardous
  ultraviolet radiation strikes the earths surface
  due to depletion of the ozone layer.
• Population reduction will occur by increased
  fatalities from natural disasters, mass
  starvation, epidemics, and ecological degredation.

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Overpopulation Scenario TwoThe Gaia Hypothesis

• Gaia - Greek Goddess of the Earth
• Proposed by James Lovelock and Lynn Margulis.

• Stated that life is an important regulator of
  the earth environment, where the earth is like a
  super organism whose environment is controlled
  by the plants and animals that inhabit it.

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Toward a Sustainable Society

• A sustainable society is one that satisfies its
  needs without jeopardizing the needs of future
  generations.
• Regulate our food, fuel, air, water, resources
  for the interests of future generations.
• SOLUTIONS
• Reduce population growth
• Limit resource consumption (reduce, reuse,
  recycle)
• Reduce pollution and waste generation by more
  efficient technologies
• PROBLEM We know what needs to be done, but
  dont want or know how to do it?!?

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What to Regulate???

• U.N. Conference on Population (Cairo, 1994)

"Programme of Action" (182 nations)
Goal to stabilize human population at 7.8
billion by 2050
1. Provide universal access to family-planning
and reproductive health programs. 2. Make women
equal participants in all aspects of society - by
increasing women's health, education, and
employment. 3. Increase access to education.
Provide information and services for adolescents
to prevent unwanted pregnancies, unsafe abortion,
and the spread of AIDS and sexually transmitted
diseases. 4. Ensure that men fulfill their
responsibility to ensure healthy pregnancies,
proper child care, promotion of women's worth and
dignity, prevention of unwanted pregnancies, and
prevention of the spread of AIDS and sexually
transmitted diseases.
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What to Regulate???

• ENERGY USAGE
• Global warming - from an increase in atmospheric
  carbon dioxide produced by the burning of coal,
  oil, and natural gas, as well as other greenhouse
  gases including methane, nitrous oxide, ozone and
  CFCs.
• SOLUTIONS?
• Legally binding limits on emissions of greenhouse
  gases (The Kyoto Protocol)
• Develop cleaner sources of energy. Alternatives
  include solar, wind, geothermal, and nuclear
  energy.

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What to Regulate???

• THE LAND
• The number of people supported by earth is
  limited by the amount of useful land for
  agriculture.

• PROBLEM
• Degradation from poor agricultural practices,
  contamination, natural erosion, and erosion
  accelerated by deforestation
• Lack of soil is the cause of famine

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What to Regulate???

• WATER
• Water is a finite resource and needs to be
  managed.
• On average, seventy percent of water that is
  diverted from rivers or pumped from underground
  is used for irrigating crops. Simply put, NO
  WATER - NO FOOD.

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What to Regulate???

• FORESTS
• Deforestation caused by
• Clearing soil for agriculture
• Logging for wood, especially in the Tropics
• Demand for wood fuel and forest products
• Leads to
• loss of habitat and decreased biodiversity.
• Contributes to climate change by adding carbon
  dioxide to the atmosphere.
• soil degradation due to erosion.

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What to Regulate???

• RESOURCES
• Throw-Away Society
• Our resources are dwindling
• Geologic and environmental consequences of mining
  and energy consumption
• Trash disposal has become very expensive,
  especially in urban areas.
• RECYCLE
• Most of what we used to discard is now recycled
  paper, plastic, glass, aluminum, steel

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