Life cycle assessment, LCA, what is it used for and how can it be a great tool?
A lifecycle analysis (LCA) means that all steps involved with a product or service are described from the resource extraction, production, use, to the waste scenario (Finnveden et al., 2009; ISO, 2006a, 2006b; Pålsson & Carlson, 2011). LCA is used in many different areas, such as the construction industry and the clothing industry. The LCA framework is described below and in the figure, figure 1.
The lifecycle framework consists of four steps:
- Goal and scope definition
- Inventory analysis
- Impact assessment
From the inventory analysis a list of inflows and outflows are presented, se figure 2. This can be a list of more than a hundred flows. The list of flows that is obtained is valuable information but for a non-LCA expert it can be hard to interpret. To present the result from an LCA in a more accessible way an impact assessment is then conducted.
The impact assessment identifies what type of inflows and outflows are contributing to the different environmental impact categories. An inflow or an outflow can contribute to more than one impact category (Pålsson & Carlson, 2011). For example, the chemicals used for different types of production can have a negative impact on both global warming potential and marine eutrophication. There are several impact categories that can be accounted for when conducting an LCA e.g., acidification potential (AP), marine eutrophication (ME), Freshwater Eco Toxicity Potential (FETP) and freshwater acidification (FA), for this study only the environmental impact of global warming potential (GWP) was considered. GWP includes many airborne emissions released during the life cycle and especially the release of CO2. GWP is also one of the biggest threats to the environment today through its role in climate change and it is a much debated issue on a political level.
In the last step of the impact assessment normalization and weighting can be made. Normalization means for example that the average contribution on climate affecting gases from a European citizen is compared with the result for this study. Thereby the contribution on climate change can be better evaluated. This can be done for all environmental impact categories but the categories cannot be weighed against each other (Finnveden et al., 2009; Pålsson & Carlson, 2011). To be able to compare the results from the environmental impact categories against each other a set of different weighting factors are used. The different categories are given different values for their relative significance. For example, category A is considered to be four times more valuable than category B. Weighting is normally not conducted in an LCA since it is more of a political question than a scientific one. Also the ISO standard for LCA does not allow weighting to be performed when the results are presented to the public (ISO, 2006 b).
The last step that is necessary in a LCA is the interpretation phase. In this stage the results are assessed and then described as a final result. Despite all of the steps an LCA is not only made up out of gathered data and common knowledge, it also consists of assumptions, data gaps and decisions from the person conducting the LCA (Finnveden et al., 2009; Pålsson & Carlson, 2011).
Finnveden, G., Hauschild, M. Z., Ekvall, T., Guinée, J., Heijungs, R., Hellweg, S., … Suh, S. (2009). Recent developments in Life Cycle Assessment. Journal of Environmental Management, 91, 1–21. doi:10.1016/j.jenvman.2009.06.018
ISO. (2006a). ISO 14040 International Standard. In: Environmental Management – Life CycleAssessment – Principles and Framework. Geneva.
ISO. (2006b). ISO 14044 International Standard. In: Environmental Management – Life CycleAssessment – Requirements and Guidelines. Geneva.
Pålsson, A.-C., & Carlson, R. (2011). Livscykleanalys – Ringar på vattnet (1st ed., p. 202). SIS Förlag AB.