2.3. Life-Cycle Frameworks

Understanding life-cycle frameworks for environmental and sustainability issues requires an understanding of the language of life-cycle assessment, the tools used to quantify life-cycle impacts, and the use of life-cycle assessment in regulation. This section addresses each of these prerequisites for understanding the use of life-cycle frameworks and provides case studies of the use of life-cycle assessment tools.

2.3.1. Defining Life Cycles

While risk assessment and risk management have proven to be useful frameworks for managing environmental issues, one shortcoming of these approaches is that they tend to examine individual events (e.g., a single pollutant being emitted from a single source or group of sources) rather than systems. Decisions made to address environmental issues or sustainability often have cascading impacts through complex engineered systems. Consider, as an example, the use of biofuels to reduce the net emissions of greenhouse gases.