Semester Review

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Environmental Science

• Semester Review

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Objectives

• Define environmental science and compare
  environmental science with ecology and
  environmentalism.
• List five major fields of study that contribute
  to environmental science.
• Distinguish between a renewable resource and a
  non-renewable resource.
• Explain the concept of sustainability and why it
  is a goal in environmental science.
• Explain the concept of an Ecological Footprint

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Environmental Science

• Environmental science is the study of
• How the natural world works
• How the environment affects humans and vice versa
• We need to understand our interactions with the
  environment
• To creatively solve environmental problems

NYC Today and 400 yrs ago
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The Nature of Environmental Science

• Environment ? impacts ? Humans
• Its applied goal solving environmental problems
• Solutions are applications of science
• An interdisciplinary field
• Natural sciences examines the natural world
• Environmental science programs
• Social sciences examines values and human
  behavior
• Environmental studies programs

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Environmental science

• Can help us avoid mistakes made by past
  civilizations
• Human survival depends on how we interact with
  our environment.
• Our impacts are now global.
• Many great civilizations have fallen after
  depleting their resources.

The lesson of Easter Island people annihilated
their culture by destroying their environment.
Can we act more wisely to conserve our resources?
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Environmental Science is not Environmentalism

• Environmental science
• Pursues knowledge about the environment and our
  interactions with it
• Scientists try to remain objective and free from
  bias
• Environmentalism
• A social movement
• Tries to protect the natural world from
  human-caused changes

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Goals of Environment Science

• To understand and solve environmental problems
• Ecosystem functions
• Air Pollution
• Water Pollution
• Toxic Chemicals
• Climate Change
• Resource usage

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Ecology is the Foundation of Environmental Science

• Ecology the study of how living organisms
  interact with each other and their non-living
  environment

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Fields of Study that Contribute to Environmental
Science

• Biology the study of living organisms
• Chemistry the study chemicals and their
  interactions
• Physics the study of matter and energy
• Earth Science the study of earths nonliving
  systems
• Social Sciences the study of human populations

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We Rely on Natural Resources

• Natural resources substances and energy sources
  needed for survival
• Renewable natural resources can be replenished
• Perpetually renewed sunlight, wind, wave energy
• Renew themselves over short periods timber,
  water, soil
• These can be destroyed
• Nonrenewable natural resources unavailable after
  depletion
• Oil, coal, minerals

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Natural Resources

• Renewable resources like sunlight cannot be
  depleted.
• Nonrenewable resources like oil CAN be depleted.
• Resources like timber and clean water are
  renewable only if we do not overuse them.

Figure 1.1
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Our Ecological Footprint

• Affluence increases consumption
• Ecological footprint the environmental impact of
  a person or population
• The area of biologically productive land water
• To supply raw resources and dispose/recycle waste
• People in rich nations have much larger
  ecological footprints

If everyone consumed the amount of resources the
U.S. does, we would need 4.5 Earths!
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Overshoot

• Humans have surpassed the Earths capacity to
  support us

We are using renewable resources 30 faster than
they are being replenished
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Population Consumption

• Population growth amplifies all human impacts
• The growth rate has slowed, but we still add more
  than 200,000 people to the planet each day
• Resource consumption has risen faster than
  population
• Life has become more pleasant
• Rising consumption also amplifies our demands on
  the environment
• The 20 wealthiest nations have 55 times the
  income of the 20 poorest nations
• Three times the gap that existed 40 years ago

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Ecological Footprints are not Equal

• Not everyone benefits equally from rising
  affluence
• The ecological footprints of countries vary
  greatly
• The U.S. footprint is much greater than the
  worlds average
• In the U.S. the richest 1
• Have 25 of all income

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Sustainability is the Goal!

• Condition in which human needs are met without
  harming future generations.
• We are not living sustainably today.
• What needs to change?

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Sustainability and the Future of our World

• Sustainability we must live within our planets
  means
• So the Earth and its resources can sustain us and
  all life for the future
• Sustainability involves conserving resources
• Developing long-term solutions
• Keeping fully functioning ecosystems
• Natural capital Earths total wealth of
  resources
• We are withdrawing it faster that its being
  replenished
• We must live off Earths natural interest
  (replenishable resources), not its natural capital

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Sustainable Solutions

• Sustainable development
• using resources to satisfy current needs without
  compromising future availability of resources
• Sustainability involves
• Renewable energy sources
• Soil conservation, high-efficiency irrigation,
  organic agriculture
• Pollution reduction
• Habitat and species protection
• Recycling
• Fighting global climate change

Humanitys challenge is to develop solutions that
further our quality of life while protecting and
restoring the environment.
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Will we develop in a sustainable way?
This is the single most important question we
face.
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Objectives

• Understand the Nature of Science
• Understand how scientific inquiry and
  technological design, including mathematical
  analysis, can be used to pose questions, seek
  answers, and develop solutions.
• Describe and Apply the Scientific Process
• Describe how humanity altered the environmental
• Hunter-gatherers
• Agricultural revolution
• Industrial revolution

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The Nature of Science

• Science a systematic process for learning about
  the world and testing our understanding of it
• The accumulated body of knowledge arising from
  the dynamic process of observation, testing, and
  discovery
• Civilization depends on science and technology
• Science tries to understand the world and steer a
  safe course
• Science is essential to sort fact from fiction
• Develop solutions to the problems we face
• It must be accessible and understandable to the
  public

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Science Asks and Answers Questions

• It is an incremental approach to the truth
• Scientists do not simply accept conventional
  wisdom
• They judge ideas by the strength of their
  evidence
• Observational (descriptive) science information
  is gathered about organisms, systems, processes,
  etc.
• Cannot be manipulated by experiments
• Phenomena are observed and measured
• Used in astronomy, paleontology, taxonomy,
  genomics
• Hypothesis-driven science targeted research
• Experiments test hypotheses using the scientific
  method

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The Scientific Method A Traditional Approach

• Science tests ideas
• Scientists in different fields approach problems
  differently
• Assumptions
• The universe works according to unchanging
  natural laws
• Events arise from causes, and cause other events
• We use senses and reason to understand natural
  processes

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Applications of Science

• Policy decisions and management practices are
  applications of science.
• Prescribed burning, used to restore forest
  ecosystems altered by human suppression of fire.

Figure 1.8a
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Applications of Science

• Technology is another application of science.
• Energy-efficient methanol-powered fuel cell car
  from DaimlerChrysler

Figure 1.8b
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Scientific Method Assumptions

• Fixed natural laws govern how the universe works
• All events arise from causes, and cause other
  events
• We can use our senses and reason to detect and
  describe natures laws

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Scientific Method

• A step-by-step method for testing ideas with
  observations.
• Scientists use educated guesses called hypotheses
  to generate predictions
• hypotheses are tested experimentally.
• Results may reject or support a hypothesis.
• Results never prove a hypothesis, but only lend
  support to it by failing to reject it.

Figure 1.9
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Scientific Process

• Peer review, publication, and debate are parts of
  the larger scientific process.

Figure 1.11
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Hypothesis, Theory, and Paradigm

• Hypothesis an educated guess, to be tested
• Theory a well-tested and widely accepted
  explanation, validated by much previous research
• Paradigm a dominant view. May shift if new
  results show old results or assumptions to be
  wrong

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Experiments Test the Validity of a Hypothesis

• Variable a condition that can change
• Independent variable is manipulated
• Dependent variable is measured and depends on
  the independent variable
• Controlled experiment the effects of all
  variables are controlled
• Except the independent variable whose effect is
  being tested
• Control an un-manipulated point of comparison
• Quantitative data uses numbers
• Qualitative data does not use numbers

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Hypotheses are Tested in Different Ways

• Natural tests
• Results are not neat and clean
• Show real-world complexity
• Answers arent black and white

• Manipulative experiments
• Yield the strongest evidence
• Reveals causal relationships
• Lots of things cant be manipulated

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Human Impact Over Earths History

• Wherever humans have hunted, grown food, or
  settled we have changed the environment.
• How have those changes impacted the environment
  over human history?

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Hunter-Gatherers

• Most of human history
• Obtained food by moving around collecting plants
  and hunting wild animals.
• Affected the environment
• Set fires to drive game during hunting
• Spread plant species as they moved from place to
  place
• May have led to the disappearance of many large
  mammal species such as ground sloths, giant
  bison, mastodons, cave bears, and saber-tooth
  cats

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Agricultural Revolution

• Plants and animals were domesticated and
  population grew
• 10,000 years ago
• Life got easier
• Settlements began forming
• Impact on environment grew
• Habitat destroyed
• Artificial selection of domesticated crops
• Farmland replaced forest

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Industrial Revolution

• There was a shift to fossil fuels as an energy
  source
• Mid-1700s
• Life got easier
• Advances in technology
• Healthcare and sanitation improved
• People lived longer
• People moved to cities away from farms
• Increased environmental impact.

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Thomas Malthus and human population

• Thomas Malthus
• Population growth must be
• controlled, or it will outstrip food
• production.
• Starvation, war, disease
• Neo-Malthusians
• Population growth has disastrous effects.
• Paul and Anne Ehrlich, The Population Bomb (1968)
• Agricultural advances have only postponed crises.

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Human Population Levels Throughout History
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Loss of Biodiversity

• Biodiversity the number and variety of species
  that live in an area
• Why is loss of biodiversity a bad thing?
• Higher biodiversity healthier ecosystem
• Organisms are considered a natural resource

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We face challenges in biodiversity

• Biodiversity the cumulative number and diversity
  of living things
• Human actions have driven many species extinct
• Biodiversity is declining dramatically
• We are setting in motion a mass extinction event

Biodiversity loss may be our biggest problem
once a species is extinct, it is gone forever