Download Environmental science

Ch 1
An Introduction to
Environmental Science
Part 1: Foundations of
Environmental Science
PowerPoint® Slides prepared by
Jay Withgott and Heidi Marcum
Copyright © 2008 Pearson Education, Inc., publishing as Benjamin Cummings
Major Themes of Environmental Science
 Human population growth
 An urbanizing world
 Sustainability of our population and all of nature
 People and nature
 A global perspective
 Science and values
Gaia Hypothesis
 The belief that Earth has it’s own lifecycle
 Elephants kill trees
 Volcano’s erupt
 Lightning causes fires
 Global warming and cooling happened before without humans
 The actions of many groups of people at many
locations affects the environment of the entire world.
(CFC’s)
 Gaia hypothesis


James Lovelock and Lynn Margulis
Life affects the environment at a global level
Environment: the total of our surroundings
• All the things around us with which we
interact:
•
Living things - biotic
•
•
Nonliving things – abiotic (Natural)
•
•
Animals, plants, forests, fungi, etc.
Continents, oceans, clouds, soil, rocks, wind
Our built environment (Man-made)
•
Buildings, human-created living centers, roads,
transportation
Humans and the world around us
 Humans change the environment, often in ways not fully
understood. Ex. Pest Control, weed killers
 We depend completely on the environment for survival
 Increased wealth, health, mobility, leisure time
 But, natural systems have been degraded
 i.e., pollution, erosion and species extinction
 Environmental changes threaten long-term health and survival
 Environmental science is the study of:
 How the natural world works
 How the environment affects humans and vice versa
 Ecology – The study of the environment
Natural resources: vital to human survival
Natural resources = substances and energy sources needed for
survival
 Renewable resources:
Perpetually available: sunlight, wind, wave energy
 Renew themselves over short periods: timber, water, soil
 These can be destroyed
 Nonrenewable resources: can be depleted (May be renewable???)
 Oil, coal, minerals (not in our lifetime)

Sustainability and Carrying Capacity
 What is the maximum number of people the Earth can
sustain?
 Currently we are using resources unsustainably. (30%)

Faster than they can be replenished.
 Carrying capacity = the maximum number of
individuals of a species that can be sustained by an
environment

w/o decreasing the capacity of the environment to sustain that
same amount in the future
Sustainability
 Sustainability refers to resources and their
environment.
 Sustainable resource harvest

Same quantity of that resource can be harvested each
year for an unlimited amount of time. (Trees –
Silviculture)
 Sustainable ecosystem
 An ecosystem from which we are harvesting a resource
that is still able to maintain its essential
functions/properties. (Forest)
Sustainable Global Economy
 To achieve we must
 Develop an effective population-control
strategy.(Controversial… legal? Terra Nova)
 Completely restructure our energy programs. (Big Oil??)
 Institute economic planning that will encourage pop
control and wise use of resources.
 Implement social, legal, political and educational change.
Terra Nova Policy?
Moving Toward Sustainability
 The new paradigm
 Evolutionary rather than revolutionary.
 Inclusive, not exclusive.
 Proactive, not reactive.
 Attracting, not attacking.
 Assisting the disadvantage, not taking advantage.
Global human population growth
 More than 7 billion humans
 Why so many humans?

Agricultural revolution
 Stable

food supplies
Industrial revolution
 Urbanized
society
powered by fossil fuels
 Sanitation
medicines
 More
food
and
Thomas Malthus and human population
• Thomas Malthus
Population growth must be
restricted, or it will
outstrip food production
• Starvation, war, disease
• Predator-prey
relationships
• Neo-Malthusians
• Population growth has
disastrous effects
• Paul and Anne Ehrlich, The
Population Bomb (1968)
•
Garrett Hardin’s Tragedy of the Commons
•Unregulated exploitation leads to resource
depletion
•
Soil, air, water
•Resource users are tempted to increase use
until the resource is gone
•Solution?
•
•
•
Private ownership?
Voluntary organization to enforce responsible use?
Governmental regulations?
The “ecological footprint”
 The environmental impact
of a person or population


Amount of biologically
productive land + water
for raw materials and to
dispose/recycle waste
 Overshoot: humans have
surpassed the Earth’s
capacity
We are using 30% more of the planet’s resources than
are available on a sustainable basis!
Population Graphs
Exponential growth
Logistic Graph / S-Curve
Overpopulation
 Birth Rate
 Mortality Rate
 Total Population
 Population Density
 Immigration
 Emigration
 Catastrophic Ecents
Rule of 70
 AKA Doubling time
 Doubling time = 70/ Growth Rate (PGR)
 PGR = Net Gain (NG)/ total population
 NG = Birth Rate – Death Rate + immigration-
emigration
 Classic Example = 7% growth rate – double time = 10
years
Homework for Thursday
 Pick 2 countries
 Find birth rate, death rate, total population
 Find 2 other countries with a positive growth rate
 Find 1 country with a negative growth rate
 Find 10 megacities (populations of 8 million +)
Environmental science
… can help us avoid mistakes made by past civilizations.
The lesson of Easter Island: people annihilated their
culture by destroying their environment. Can we act
more wisely to conserve our resources?
Easter Island
 Named from Dutch Sailors who landed on Easter Sunday
 http://www.gns.cri.nz/Home/Our-Science/Environment-
Climate/Environmental-Change/Research/Easter-Islandcollapse
Definitions
 Limiting factors - things that prevent a population
from growing any larger.

Disease, food supply, natural factors, humans, predation,
nutrients
 Biotic Potential - An estimate of the maximum
capacity of living things to survive and reproduce
under optimal environmental conditions.
Continues forever.
S-Curve - Labels
 Exponential growth, transitional phase (lag time), Plateau
phase, carrying capacity, maximum sustainable yield
Precautionary Principle
 1992 - Rio Earth Summit on Sustainable Development
 Defined PP – when there is a great threat of serious
environmental damage we should not wait for
scientific proof before taking precautionary steps to
prevent potential harm.
Precautionary Principle
 PP is a proactive, rather
than a reactive, tool.
 Adopted by the city of SF
and the European Union
Placing a Value on the Environment
 The value of the environment
based on 8 justifications
 Utilitarian
 Ecological
 Aesthetic
 Recreational
-- Inspirational
 Creative
 Moral
 Cultural
Placing a Value on the Environment
 Utilitarian- the environment has value because it
benefits individuals economically or is necessary for
human survival.
 Ecological- ecosystem is necessary for survival of
some species of interest or that the system itself
provides benefit.
Placing a Value on the Environment
 Aesthetic- has to do with our appreciation of the
beauty of nature.



Recreational- viewing organisms in a natural setting.
Inspirational- to benefit the inner self
Creative- aid to human creativity
Placing a Value on the Environment
 Moral- the belief that various aspects of the
environment have the right to exist and it is our
obligation to allow them to continue.
End of lecture day 1
The nature of science
 Science:
 A systematic process for learning about the world and testing our
understanding of it
 A dynamic process of observation, testing, and discovery
 The accumulated body of knowledge that results from this
process
 Science is essential
 To sort fact from fiction
 Develop solutions to the problems we face
Applications of science
Policy decisions and
management practices
Technology
Energy-efficient methanolpowered fuel cell car from
DaimlerChrysler
Restoration of forest ecosystems
altered by human suppression of fire
The scientific method
 A scientist makes an observation
and asks questions of some
phenomenon
 The scientist formulates a
hypothesis, a statement that
attempts to explain the scientific
question.
 The hypothesis is used to generate
predictions, which are specific
statements that can be directly and
unequivocally tested.
 The test results either support or
reject the hypothesis
The scientific process is part of a larger process
• The scientific process
includes peer review,
publication, and debate
• A consistently
supported hypothesis
becomes a theory, a
well-tested and widely
accepted explanation
• With enough data, a
paradigm shift – a
change in the dominant
view – can occur
Types of Data
 Data are recorded observations or items of
information
 Data fall into two categories


Qualitative, or descriptions rather than measurements
Quantitative, or recorded measurements, which are sometimes
organized into tables and graphs
Copyright © 2008 Pearson Education, Inc., publishing as Pearson Benjamin Cummings
Induction in Discovery Science
 Inductive reasoning draws conclusions through a
limited set of observations
 Repeat specific observations can lead to important
generalizations

For example, “the sun always rises in the east”
 Deductive reasoning draws conclusions from
initial definitions and assumptions by means of
logical reasoning (transitive property of equality)



Mr. Daly is a human
Humans are mortal
Mr. Daly is mortal
Copyright © 2008 Pearson Education, Inc., publishing as Pearson Benjamin Cummings
The Role of Hypotheses in Inquiry
 A hypothesis is a tentative answer to a well-framed
question
(If-Then statement)
 A scientific hypothesis leads to predictions that can
be tested by observation or experimentation
Copyright © 2008 Pearson Education, Inc., publishing as Pearson Benjamin Cummings
A Closer Look at Hypotheses in Scientific Inquiry
 A hypothesis must be testable and falsifiable
 Hypothesis-based science often makes use of two or
more alternative hypotheses
 Failure to falsify a hypothesis does not prove that
hypothesis

For example, you replace your flashlight bulb, and it now
works; this supports the hypothesis that your bulb was burnt
out, but does not prove it (perhaps the first bulb was inserted
incorrectly)
Copyright © 2008 Pearson Education, Inc., publishing as Pearson Benjamin Cummings
Designing Controlled Experiments
 A controlled experiment compares an experimental
group (the artificial kingsnakes) with a control group (the
artificial brown snakes)
 Ideally, only the variable of interest (the color pattern of the
artificial snakes) differs between the control and
experimental groups
 A controlled experiment means that control groups are used
to cancel the effects of unwanted variables
 A controlled experiment does not mean that all unwanted
variables are kept constant
Copyright © 2008 Pearson Education, Inc., publishing as Pearson Benjamin Cummings
Limitations of Science
 In science, observations and experimental results
must be repeatable
 Science cannot support or falsify supernatural
explanations, which are outside the bounds of
science
Copyright © 2008 Pearson Education, Inc., publishing as Pearson Benjamin Cummings
Theories in Science
 In the context of science, a theory is:
 Broader in scope than a hypothesis
 General, and can lead to new testable hypotheses
 Supported by a large body of evidence in comparison to a
hypothesis
Copyright © 2008 Pearson Education, Inc., publishing as Pearson Benjamin Cummings
Model Building in Science
 Models are representations of natural phenomena
and can take the form of:




Diagrams
Three-dimensional objects
Computer programs
Mathematical equations
Copyright © 2008 Pearson Education, Inc., publishing as Pearson Benjamin Cummings
The Culture of Science
 Most scientists work in teams, which often include
graduate and undergraduate students
 Good communication is important in order to share
results through seminars, publications, and websites
Copyright © 2008 Pearson Education, Inc., publishing as Pearson Benjamin Cummings
Science, Technology, and Society
 The goal of science is to understand natural
phenomena
 The goal of technology is to apply scientific
knowledge for some specific purpose
 Science and technology are interdependent
 Biology is marked by “discoveries,” while technology
is marked by “inventions”
Copyright © 2008 Pearson Education, Inc., publishing as Pearson Benjamin Cummings
 The combination of science and technology has
dramatic effects on society

For example, the discovery of DNA by James Watson and
Francis Crick allowed for advances in DNA technology such as
testing for hereditary diseases
 Ethical issues can arise from new technology, but
have as much to do with politics, economics, and
cultural values as with science and technology
Copyright © 2008 Pearson Education, Inc., publishing as Pearson Benjamin Cummings
Population & consumption
 Human population growth exacerbates all
environmental problems

The growth rate has slowed, but we still add more than
200,000 people to the planet each day
 Our consumption of resources has risen even faster
than our population growth.


Life has become more pleasant for us so far
However, rising consumption amplifies the demands we make on
our environment.
The Millennium Ecosystem Assessment
The most comprehensive scientific assessment of
the condition of the world’s ecological systems
Major findings:
•
•
•
•
•
•
Humans have drastically altered ecosystems
These changes have contributed to human well-being and
economic development, but at a cost
Environmental degradation could get much worse
Degradation can be reversed, but it requires work
Our energy choices will affect our future
•
•The lives we live today are due to fossil fuels
•
•
•
•
•
Machines
Chemicals
Transportation
Products
Fossil fuels are a one-time bonanza; supplies will certainly
decline
We have used up ½ of the world’s oil supplies; how will we
handle this imminent fossil fuel shortage?
Sustainable solutions exist
 We must develop solutions that protect both our
quality of life and the environment
 Organic agriculture
 Technology

Reduces pollution
 Biodiversity

Protect species
 Waste disposal

Recycling
 Alternative fuels
Are things getting better or worse?
• Many people think environmental conditions are
better
•
Cornucopians: Human ingenuity will solve any problem
• Some think things are much worse in the world
• Cassandras: predict doom and disaster
• How can you decide who is correct?
• Are the impacts limited to humans, or are other organisms or
systems involved?
• Are the proponents thinking in the long or short term?
• Are they considering all costs and benefits?
Sustainability: a goal for the future
 How can humans live within the planet’s means?
 Humans cannot exist without functioning natural systems
 Sustainability
 Leaves future generations with a rich and full Earth
 Conserves the Earth’s natural resources
 Maintains fully functioning ecological systems
 Sustainable development: the use of resources to
satisfy current needs without compromising future
availability of resources
Conclusion
 Environmental science helps us understand our
relationship with the environment and informs our
attempts to solve and prevent problems.
 Identifying a problem is the first step in solving it
 Solving environmental problems can move us towards
health, longevity, peace and prosperity

Environmental science can help us find balanced solutions to
environmental problems
QUESTION: Review
Which of the following is correct about the term
“environmentalism”?
a)
b)
c)
d)
It is very science-oriented
It is a social movement to protect the environment
It usually does not include advocacy for the environment
It involves scientists trying to solve environmental problems
QUESTION: Review
Adding various amounts of fertilizer to plants in a
laboratory is a _____ type of experiment
a)
b)
c)
d)
Correlative
Natural
Manipulative
Rare
QUESTION: Review
What is the definition of “sustainable development”?
a)
b)
c)
d)
Using resources to benefit future generations, even if it
means lower availability now
Letting future generations figure out their own problems
Using resources to satisfy current needs without
compromising future availability
Letting each country decide what is its best interest
QUESTION: Weighing the Issues
Which do you think is the best way to protect commonly
owned resources (i.e., air, water, fisheries)?
a)
b)
c)
d)
Sell the resource to a private entity
Voluntary organizations to enforce responsible use
Governmental regulations
Do nothing and see what happens
QUESTION: Weighing the Issues
Do you think the rest of the world can have an
ecological footprint as large as the footprint of the
United States?
a)
b)
c)
d)
Yes, because we will find new technologies and resources
Yes, because the footprint of the United States is not really
that large
Definitely not; the world does not have that many
resources
It does not matter; it’s not that important
QUESTION: Interpreting Graphs and Data
According to this graph, what has happened to the
population over the last 500 years?
a) It has grown
exponentially
b) It has grown
linearly
c) It has decreased
d) It has slowed
down recently
QUESTION: Interpreting Graphs and Data
What happens if test results
reject a hypothesis?
a) The scientist formulates a
new hypothesis
b) It shows the test failed
c) The hypothesis was
supported
d) The predictions may not
have been correct