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– 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.