What are the basic principles of industrial ecology? What is the difference between a "straight-line" and circular process? What are dematerialization, materials substitution, and waste mining? How can growth in GDP be decoupled from growth in material inputs? What are some ways to make agricultural systems compatible with natural ecosystems? How has the global demand for materials changed over the past few decades? How are gains in material efficiency offset by other factors? What is the relationship between the intensity of materials use and the IPAT equation? What is the concept of "sufficiency"? What are some policies that could be used to promote industrial ecology?