Life Cycle Assessment (LCA): Measuring the Impacts of Systems in Multi-part Processes

Life Cycle Assessments

Life cycle assessments or life cycle analyses (LCAs) are defined as "a tool to analyze the potential environmental impacts of products at all stages in their life cycle" (International Standards Organization). Analogous to the food supply chain activity you completed in module 10.1, LCAs follow products (foods and otherwise) from production, through transport and assembly steps, to the consumption or operation of the product, and in some cases even its disposal. In contrast to the supply chain descriptions in module 10.1, at each of these stages of production, transport, consumption, and disposal, LCAs keep a running total of environmental costs or impacts of the product. Common impacts that are tracked by LCAs across product life cycles are greenhouse gas emissions, water pollution impacts, and energy use. As such LCAs are a key tool in analyzing the impacts of human on natural earth surface systems within the coupled natural-human food system (Fig. 10.2.3). LCAs require some careful thinking about where to draw the boundaries of the system for considering the life cycle of a product. For example, an LCA devoted to carrots would probably include the energy required to operate the refrigerated truck used to transport the carrots but not the energy needed to make the truck. Also, many LCAs are "cradle to grave" and include both impacts of all raw materials used in production as well as disposal impacts for the product, but some do not focus on the entire life cycle and assess other segments of the lifecycle such as "cradle to farm-gate" or "cradle to plate" in the case of food products.

Life cycle analyses are an excellent way of putting into practice a geosciences "habit of mind" of using systems thinking. Because food systems are complex, we think about a way to measure its performance and then explore all the linkages in the system within that single metric or measurement parameter (see module 1.2 for a discussion of complex systems behavior). That is, we don't content ourselves with just thinking about a crop plant in a field, the entire farm field, or the highway where foods are transported; we go several levels up to measure impacts along the entire pathway or web of interacting system parts. Along the way, it is likely that we will start to think in new ways about the linkages between parts of the system, about the most important contributions to impact, or about previously hidden factors or unexpected outcomes that explain the performance of the system.

Required Reading

National Center for Appropriate Technology (NCAT): Life Cycle Assessment of Agricultural Systems, pp. 1-3 and figure 3 for light bulb LCA on page 9.

You'll notice that the presentation of compact fluorescent light bulbs is somewhat dated since there has now been a big move to LED light bulbs that are further reducing energy usage for lighting. We continue to feature this presentation of LCA from the NCAT because it is one of the better non-technical introductions to the subject and also relates LCA concepts to agriculture. See the resources below if you want to read more about LCAs, including a detailed PowerPoint comparing different types of light bulbs.

Additional Reading on LCAs (optional)

1. Colin Sage's book, Environment, and Food, pp. 167-172, Chapter 5, Final foods and their consequences. You may remember that the first few pages of this book were assigned as a reading in module 1.1. This document may be available through your E-Reserve System.
2. A PowerPoint comparison of light bulbs to complement the reading from NCAT above, H. Dillon and C. Ross: "Updating the LED Life-Cycle Assessment (Acrobat (PDF) 562kB Jan3 18)".
3. A video of a "six-minute crash course, LCA 6 minute crash course Life cycle thinking and sustainability in design, by Leyla Acarogluintroducing.