Transcript File - Down the Rabbit Hole

Environmental Science
Semester Review
Objectives
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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
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
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NYC Today and 400 yrs ago
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
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?
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
Goals of Environment Science
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To understand and
solve environmental
problems
–
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–
–
–
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Ecosystem functions
Air Pollution
Water Pollution
Toxic Chemicals
Climate Change
Resource usage
Ecology is the Foundation of
Environmental Science
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Ecology: the study
of how living
organisms
interact with each
other and their
non-living
environment
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 earth’s nonliving
systems
 Social Sciences: the study of human
populations
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We Rely on Natural Resources
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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
Natural Resources
Renewable resources like sunlight cannot be depleted.
 Nonrenewable resources like oil CAN be depleted.
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Resources like timber and clean water are renewable
only if we do not overuse them.
Figure 1.1
Our “Ecological Footprint”
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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!
Overshoot
 Humans have surpassed the Earth’s capacity
to support us
We are using renewable resources 30% faster
than they are being replenished
Population & Consumption
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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
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Resource consumption has risen faster than
population
– Life has become more pleasant
– Rising consumption also amplifies our demands on
the environment
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The 20 wealthiest nations have 55 times the
income of the 20 poorest nations
– Three times the gap that existed 40 years ago
Ecological Footprints are not Equal
Not everyone benefits
equally from rising
affluence
 The ecological footprints
of countries vary greatly
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– The U.S. footprint is much
greater than the world’s
average
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In the U.S. the richest 1%
– Have 25% of all income
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
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Sustainability: we must live within our planet’s 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: Earth’s total wealth of resources
– We are withdrawing it faster that it’s being replenished
– We must live off Earth’s natural interest (replenishable
resources), not its natural capital
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
Humanity’s challenge is to develop solutions that further our
quality of life while protecting and restoring the environment.
Will we develop
in a sustainable way?
This is the single
most important
question we
face.
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
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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
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Civilization depends on science and technology
– Science tries to understand the world and steer a safe course
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Science is essential to sort fact from fiction
– Develop solutions to the problems we face
– It must be accessible and understandable to the public
Science Asks and Answers
Questions
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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
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Hypothesis-driven science: targeted research
 Experiments test hypotheses using the scientific method
The Scientific Method:
A Traditional Approach
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Science tests ideas
– Scientists in different fields approach
problems differently
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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
Applications of Science
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Policy decisions and
management practices
are applications of
science.
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Prescribed burning, used
to restore forest
ecosystems altered by
human suppression of fire.
Figure 1.8a
Applications of Science
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Technology is
another application
of science.
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Energy-efficient
methanol-powered
fuel cell car from
DaimlerChrysler
Figure 1.8b
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 nature’s laws
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Scientific Method
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A step-by-step method for testing
ideas with observations.
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Scientists use educated guesses
called hypotheses to generate
predictions
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hypotheses are tested
experimentally.
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Results may reject or support a
hypothesis.
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Results never prove a hypothesis,
but only lend support to it by
failing to reject it.
Figure 1.9
Scientific Process
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Peer review,
publication, and
debate are parts
of the larger
scientific process.
Figure 1.11
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
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– 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
Manipulative experiments
• Yield the strongest evidence
• Reveals causal relationships
• Lots of things can’t be
manipulated
Natural tests
• Results are not neat and clean
• Show real-world complexity
• Answers aren’t black and
white
Human Impact Over Earth’s History
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Wherever humans
have hunted,
grown food, or
settled we have
changed the
environment.
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How have those
changes impacted
the environment
over human
history?
HunterGatherers
Most of human history
 Obtained food by moving
around collecting plants
and hunting wild animals.
 Affected the environment:
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– 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
Agricultural
Revolution
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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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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.
Industrial
Revolution
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)
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Agricultural advances have only postponed crises.
Human Population Levels
Throughout History
Loss of Biodiversity
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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
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