The document discusses key concepts related to environmental sustainability including overpopulation, overconsumption, ecological footprints, and what a sustainable world entails. It notes that most environmental problems can be traced to overpopulation and overconsumption, and that developed countries consume 75% of resources while housing only 20% of the population. A sustainable world is one where human needs are met indefinitely without depleting resources.

1. Sustainability Environmental Science Spring 2010

2. Sustainability Sustainability - When human needs are met in such a way that a human population can survive indefinitely One of the key goals of environmental science is to achieve sustainability

3. “The Tragedy of the Commons” The main difficulty in solving environmental problems is the conflict between short-term interests of individuals and long-term welfare of society Someone has to take responsibility for maintaining a resource, or it will become overused and depleted.

4. Economic Pressures Law of Supply and Demand – the greater the demand for a limited supply of something, the greater the worth Cost-Benefit Analysis – balances the cost of doing something with the benefits of doing it Risk Assessment – determination of the risks of an undesirable outcome

5. Population and Consumption Most environmental problems can be traced to two root problems Overpopulation - The population in the area is growing too fast for the local environment to support. Over consumption - People are using up, wasting, or polluting resources faster than they can be replaced.

6. Overpopulation In severely overpopulated areas forests are stripped bare, topsoil is exhausted, and animals are driven to extinction. Food production, education, and job creation cannot keep up with population growth, so each person gets fewer resources as time goes by.

7. Over Consumption In wealthier countries the population is more stable, and there is a high quality of life However, developed countries consume 75% of the Earth’s resources, but only house 20% of the population. The rate of consumption produces more waste and pollution per person

8. Ecological Footprints An ecological footprint shows the productive area of Earth needed to support one person in a country It includes estimates for : Land used for crops, grazing animals, forest products, housing, waste storage Ocean area for harvesting seafood Forest area needed to absorb air pollution

9. What is a sustainable world?