Chapter 1: Key Themes in
Environmental Sciences
Major Themes of Environmental
Science
• Our population has more than doubled in
the last 40 years
– 6.8 billion people alive today
• Continuing on this trend would lead to 9.4
billion by 2050
• How many people can the Earth sustain?
– Depends on science and value
– Also question of people and nature
Human Population Growth
• John Eli Miller Family
– Example of family population explosion
Human Population Growth
• Miller family emphasizes a major factor in
modern population explosion
–
–
–
–
Modern technology
Modern medicine
Supply of food, clothing and shelter
All decrease the death rate and increase net
growth rate
Our Rapid Population Growth
• Human population growth is the underlying
issue of the environment.
– Damage is directly or indirectly due to pop inc
Famine and Food Crisis
• Famine occurs when human pop exceeds its
environmental resources
• Sahel region of Africa in 1970s
– ½ million people starved to death
– Millions affected by malnutrition
• Emerging global food crisis
– Due to rise in fuel cost = higher food cost
Famine and Food Crisis
Food Crisis
Sustainability and Carrying
Capacity
• What is the maximum number of people the
Earth can sustain?
– Much of this book will help answer that ?
• Currently we are using resources
unsustainably.
– Faster that they can be replenished.
Sustainability: The Environmental
Objective
• Is Earth very survival really in danger?
– Earth will go on w/o us
– Quality of human enviro at risk
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.
• Sustainable ecosystem
– An ecosystem from which we are harvesting a
resource that is still able to maintain its
essential functions/properties.
Sustainability
• Two points to understanding sustainability
– Sustainability means for an unspecified long
period of time.
– Sustainable growth is an oxymoron.
Sustainable Global Economy
• Population of humans living in harmony w/
natural support systems.
• An energy policy that does not pollute, cause
climate change or present unacceptable risk.
• A plan for renewable resources that will not
deplete the resources or damage ecosystems.
Sustainable Global Economy
• A plan for nonrenewable resources that
does not damage region or global environ.
– And provides a share for future generations
• A social, legal, and political system that is
dedicated to sustainability.
Sustainable Global Economy
• To achieve we must
– Develop an effective population-control strategy.
– Completely restructure our energy programs.
– Institute economic planning that will encourage
pop control and wise use of resources.
– Implement social, legal, political and eductional
change.
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.
Carrying Capacity of the Earth
• Defined as
– the maximum number of ind of a species that
can be sustained by an environment
– w/o decreasing the capacity of the environ to
sustain that same amount in the future
A Global Perspective
• The actions of many groups of people at
many locations affects the environment of
the entire world.
• Gaia hypothesis
– James Lovelock and Lynn Margulis
– Life affects the environment at a global level
An Urban World
• We are
becoming an
urban species
• In developed
countries
– 75% live in
urban area
• Developing
countries
– 40%
An Urban World
• Megacity
– Urban area
with at least
10 million
inhabitants
People and Nature
• We depend on nature directly for
– Wood
– Water
– Air
• And indirectly for “public services
functions”
– E.g. soil formation
Soil Fertility and Structure
People and Nature
• People and animals
alter and change
their environment.
• Dichotomy of 20th
century is giving
way.
• New unity
– Sustainable environ
and economy
compatible.
Science and Values
• We must choose what we want the
environment to be
• Value judgment regarding the world’s
human population problem
– Choice between desire to have large family and
the need to limit the human population.
• The more high tech and powerful our
civilization, the more knowledge is
required.
Fishing for Salmon
Precautionary Principle
• 1992 - Rio Earth Summit on Sustainable
Development
• Defined PP – when there is a great threat of
serious environ 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
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–
–
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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.