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.