Chapter 1 Introducing Environmental Science and Stability

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Chapter 1Introducing Environmental Science and
Stability
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Overview of Chapter 1

• Human Impacts on The Environment
• Population, Resources and the Environment
• Environmental Sustainability
• Environmental Science
• Assessing Environmental Problems

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The Environment (Earth)

• Life has existed on earth for 3.8 billion years
• Earth well suited for life
• Water covers ¾ of planet
• Habitable temperature
• Moderate sunlight
• Atmosphere provides oxygen and carbon dioxide
• Soil provides essential minerals for plants
• But humans are altering the planet not always in
  positive ways

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Human Impacts on Environment- Population

• Earths Human Population is over 7 billion
• Growing exponentially
• Expected to add several billion more people in
  21st century
• Increase will adversely affect living conditions
  in many areas of the world

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Population

• Globally, 1 in 4 people lives in extreme poverty
• Cannot meet basic need for food, clothing,
  shelter, health
• Difficult to meet population needs without
  exploiting earths resources

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Gap Between Rich and Poor

• Highly Developed Countries (HDC)
• Complex industrialized bases, low population
  growth, high per capita incomes
• Ex US, Canada, Japan
• Less Developed Countries (LDC)
• Low level of industrialization, very high
  fertility rate, high infant mortality rate, low
  per capita income
• Ex Bangladesh, Mali, Ethiopia

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Types of Natural Resources
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Overpopulation

• People overpopulation
• Too many people in a given geographic area
• Problem in many developing nations
• Consumption overpopulation
• Each individual in a population consumes too
  large a share of the resources
• Problem in many highly developed nations

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Ecological Footprint

• The average amount of land, water and ocean
  required to provide that person with all the
  resources they consume

Earths Productive Land and Water 11.4 billion hectares
Amount Each Person is Allotted (divide Productive Land and Water by Human Population) 1.9 hectares
Current Global Ecological Footprint of each person 2.3 hectares
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Ecological Footprint Comparison
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IPAT Model

• Measures 3 factors that affect environmental
  impact (I)

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Environmental Sustainability

• The ability to meet current human need for
  natural resources without compromising the needs
  of future generations
• Requires understanding
• The effects of our actions on the earth
• That earths resources are not infinite

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Tragedy of the Commons

• Garrett Hardin (1915-2003)
• Solving Environmental Problems is result of
  struggle between
• Short term welfare
• Long term environmental stability and societal
  welfare
• Garrett used Common Pastureland in medieval
  Europe to illustrate the struggle

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Sustainable Development

• Economic development that meets the needs of the
  present generation without compromising future
  generations

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Environmental Science

• An interdisciplinary study of human relationship
  with other organisms and the earth
• Biology
• Ecology
• Geography
• Chemistry
• Geology
• Physics
• Economics
• Sociology
• Demography
• politics

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Earth As a System

• System
• A set of components that interact and function as
  a whole
• Global Earth Systems
• Climate, atmosphere, land, coastal zones, ocean
• Ecosystem
• A natural system consisting of a community of
  organisms and its physical environment
• System approach to environmental science
• Helps us understand how human activities effect
  global environmental parameters

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Earth Systems

• Most of earths systems are in dynamic
  equilibrium or steady state
• Rate of change in one direction equals that in
  the other
• Feedback
• Change in 1 part of system leads to change in
  another
• Negative feedback- change triggers a response
  that counteracts the changed condition
• Positive feedback- change triggers a response
  that intensifies the changing condition

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Scientific Method
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Controls and Variables in Experiment

• Variable
• A factor that influences a process
• The variable may be altered in an experiment to
  see its effect on the outcome
• Control
• The variable is not altered
• Allows for comparison between the altered
  variable test and the unaltered variable test

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Inductive and Deductive Reasoning

• Inductive Reasoning
• Used to discover general principles
• Seeks a unifying explanation for all the data
  available
• Ex
• FACT Gold is a metal heavier than water
• FACT Iron is metal heavier than water
• FACT Silver is a metal heavier than water
• CONCLUSION (based on inductive reasoning) All
  metals are heavier than water
• Conclusions reached with inductive reasoning may
  change with new information

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Inductive and Deductive Reasoning

• Deductive Reasoning
• Proceeds from generalities to specifics
• Adds nothing new to knowledge, but makes
  relationships among data more apparent
• Ex
• GENERAL RULE All birds have wings
• SPECIFIC EXAMPLE Robins are birds
• CONCLUSION (based on deductive reasoning) All
  Robins have wings

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Five Stages to Addressing An Environmental Problem

• Five steps are idealistic
• Real life is rarely so neat
• The following slides illustrate a Case Study
  using the Five Stages

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Assessing Environmental ProblemCase Study Lake
Washington

• Large, freshwater pond
• Suburban sprawl in 1940s
• 10 new sewage treatment plants dumped effluent
  into lake
• Effect excessive cyanobacteria growth that
  killed off fish and aquatic life

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Assessing Environmental ProblemCase Study Lake
Washington

• Scientific Assessment
• Aquatic wildlife assessment done in 1933 was
  compared to the 1950 assessment
• Hypothesized treated sewage was introducing high
  nutrients causing growth of cyanobacteria
• Risk Analysis
• After analyzing many choices, chose new location
  (freshwater) and greater treatment for sewage to
  decrease nutrients in effluent

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Assessing Environmental ProblemCase Study Lake
Washington

• Public Education/Involvement
• Educated public on why changes were necessary
• Political Action
• Difficult to organize sewage disposal in so many
  municipalities
• Changes were not made until 1963!
• Evaluation
• Cyanobacteria slowly decreased until 1975 (gone)

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Assessing Environmental ProblemCase Study Lake
Washington

• Results!