ABSTRACT

This chapter focuses on a concept that seeks to assess the entire resource and ecological impact of human societies: that of ‘metabolism’. The term is most commonly used to describe processes that occur within a living organism to maintain life, but it can be used as a powerful analogy and method for assessing resource consumption and waste production by human societies, at different scales of organisation, including settlements. These processes define the essential state of sustainability of society and by highlighting key flows of resources, we can identify priority areas for intervention. This chapter briefly describes some of the key tools and concepts that have been used to assess flows of these resources using different types of metabolic impact assessments, including material flow analysis (MFA), environmentally extended input-output analysis (EE-IO), life cycle analysis (LCA), the carbon footprint (CF) and the ecological footprint (EF). Each of these methods have their own strengths and weaknesses and no single method captures all of the material and energy flows and emissions in a way which meets all the needs of policy makers or is able to portray environmental impacts to the public.