Key Themes in Environmental Sciences Chapter 1 Key Themes in Environmental Sciences

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

Human Population Growth The human population grew at a rate unprecedented in history in the twentieth century. Population growth is the underlying environmental problem. What are some examples of how a growing human population affects the environment?

Population change since 1950 projected to the year 2150 for major areas of the world, medium fertility scenario. The population of Africa will nearly quadruple. The only major area whose population is projected to drop over time is Europe – from 728 million to 595 million, a decline of 18% over 155 years. © 2008 John Wiley and Sons Publishers

Human Population AD1 - 100 million people 1960 - 3 billion people Today - 7 billion people 2050 - 9 billion people

An Urban World When the impact of technology is combined with the impact of population, the impact on the environment is multiplied. In an increasingly urban world, we must focus much of our attention on the environments of cities and on the effects of cities on the rest of the environment.

Examples Urban sprawl takes over good agricultural land. Pavement Water recreation

Sustainability and Carrying Capacity What is the maximum number of people the Earth can sustain? Population increases due to – education and economics Population decreases due to – war, famine, disease and weather

Sustainability Sustainable resource harvest Sustainable ecosystem An amount of a resource that can be harvested at regular intervals indefinitely Sustainable ecosystem An ecosystem that is subject to some human use, but at a level that leads to no loss of species or of necessary ecosystem functions

What does this mean ?? Insuring that future generations have equal opportunity to the resources that we currently enjoy

Carrying Capacity Maximum # of individuals of a species that an ecosystem can carry – without – decreasing the ability for that ecosystem to carry the same amount in the future.

Science and Values To make decisions about an environmental problem we: Know what is possible based on science Choose the best option based on our values

Precautionary Principle Precautionary Principle states that we should not wait for scientific proof before taking action to prevent environmental damage. Global Warming ? Water Shortage ?

Assignment Read Pages 13 and 15 Justifying the value of the Environment !! List the justification and give an example for each Read the “Critical Thinking” on page 14 Answer the question #1 and hand in for a classwork grade.