Indicator selection in life cycle assessment to enable decision making: issues and solutions
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With an ever increasing list of indicators available, life cycle assessment (LCA) practitioners face the challenge of effectively communicating results to decision makers. Simplification of LCA is often limited to an arbitrary selection of indicators, use of single scores by using weighted values or single attribute indicators. These solutions are less attractive to decision makers, since value judgments are introduced or multi-indicator information is lost. Normalization could be a means to narrow the list of indicators by ranking indicators vs. a reference system. This paper shows three different normalization approaches that produce very different ranking of indicators. It is explained how normalization helps maintain a multi-indicator approach while keeping the most relevant indicators, allowing effective decision making.
The approaches are illustrated on a hand dishwashing case study, using ReCiPe as the impact assessment method and taking the European population (year 2000) as the reference situation. Indicators are ranked using midpoint normalization factors, and compared to the ranking from endpoint normalization broken down by midpoint contribution.
Results and discussion
Endpoint normalization shows Resources as the most relevant area of protection for this case, closely followed by Human Health and Ecosystem. Broken down by their key driving midpoints, fossil depletion, climate change and, to a lesser extent, particulate matter formation and metal depletion, are most relevant. Midpoint normalization, however, indicates Freshwater Eutrophication, Natural Land Transformation and Toxicity indicators (marine and freshwater ecotoxicity and human toxicity) are most relevant.
A three-step approach based on endpoint normalization is recommended to present only the most relevant indicators, allowing more effective decision making instead of communicating all LCA indicators. The selection process breaks out the normalized endpoint results into the most contributing midpoints (relevant indicators) and reports results with midpoint level units. Bias due to lack of data completeness is less of an issue in the endpoint normalization process (compared to midpoint normalization), while midpoint results are less subject to uncertainty (compared to endpoint results). Focusing on the relevant indicators and key contributing unit processes has proven to be effective for non-LCA expert decision makers to understand, use, and communicate complex LCA results.
KeywordsData completeness Decision making Hand dishwashing product Life cycle impact assessment Multi-indicator Normalization
- AISE Charter for Sustainable Cleaning (2012) http://www.sustainable-cleaning.com/en.home.orb, accessed on September 25, 2012
- Ecoinvent v2.2 (2010) The Ecoinvent Centre, www.ecoinvent.org/database. Accessed September 25, 2012
- Environmental footprint of products. 2012. [Online] European Commission. Retreived in March 2012. http://ec.europa.eu/environment/eussd/product_footprint.htm
- Environmental footprint of organisations (2012) [Online] European Commission. Retrieved in March 2012. http://ec.europa.eu/environment/eussd/corporate_footprint.htm
- European Commission (2010) Joint research centre. analysis of existing environmental impact assessment methodologies for use in life cycle assessment. European Union, IspraGoogle Scholar
- Frischknecht R., Steiner R, Jungbluth N (2009) The ecological scarcity method—Eco-Factors 2006: A method for impact assessment in LCA. Bern, Switzerland: Swiss Federal Office for the Environment (FOEN), 2009. Umwelt-Wissen Nr. 0906Google Scholar
- Goedkoop MJ, Heijungs R, Huijbregts M, De Schryver A, Struijs J, van Zelm R (2008) ReCiPe 2008, A life cycle impact assessment method which comprises harmonised category indicators at the midpoint and the endpoint level. First edition Report I: Characterisation. 6 January 2009. http://www.lcia-recipe.net
- The Greenhouse Gas Protocol (2012) Standards. Greenhouse Gas Protocol. [Online] http://www.ghgprotocol.org/standards. accessed on September 25, 2012
- Heijungs R, Guinée J, Kleijn R, Rovers V (2007) Bias in normalization: causes, consequences, detection and remedies. Int J Life Cycle Assess 12(4):211–216Google Scholar
- HERA initiative (2012) http://www.heraproject.com/Index.cfm, accessed on September 25, 2012
- ISO 14044 (2006) Environmental management—life cycle assessment: requirements and guidelines. ISO 14044, GenevaGoogle Scholar
- ISO/CD 14046 (2012) Life cycle assessment—water footprint—requirements and guidelines. The International Standard Organization. [Online] http://www.iso.org/iso/iso_catalogue/catalogue_tc/catalogue_detail.htm?csnumber=43263. accessed on September 25, 2012
- ISO 14067 (2010) Carbon footprint of products—part 1: quantification. s.l.: The International Standard Organisation, 2010Google Scholar
- PAS 2050 (2011) Specification for the assessment of the life cycle greenhouse gas emissions of goods and services. s.l.: The British Standards Association, 2011. ISBN 978 0 580 71382 8Google Scholar
- REACH regulation (2006) Regulation (EC) No 1907/2006 of the European Parliament and of the Council of 18 December 2006 concerning the Registration, Evaluation, Authorisation and Restriction of Chemicals (REACH), establishing a European Chemicals Agency, amending Directive 1999/45/EC and repealing Council Regulation (EEC) No 793/93 and Commission Regulation (EC) No 1488/94 as well as Council Directive 76/769/EEC and Commission Directives 91/155/EEC, 93/67/EEC, 93/105/EC and 2000/21/EC, Official J European Union, L396, 30.12.2006 p.1-849Google Scholar
- Rosenbaum R, Bachmann TM, Gold LS, Huijbregts MAJ, Joliet O, Juraske R, Koehler A, Larsen HF, Macleod M, Margni M, McKone TE, Payet J, Schuhmacher M, van de Meent D, Hauschild MZ (2008) USEtox—the UNEP-SETAC toxicity model: recommended characterization factors for human toxicity and freshwater ecotoxicity in life cycle assessment. Int J Life Cycle Assess 13(7):532–546CrossRefGoogle Scholar
- Steen B (1999) A systematic approach to environmental strategies in product development (EPS). Version 2000 - General system characteristics. Centre for Environmental Assessment of Products and Material Systems. Chalmers University of Technology, Technical Environmental Planning. CPM report 1999:4. [online] http://www.cpm.chalmers.se/cpm/publications/EPS2000.PDF
- Sustainability Consortium (2012) [Online] Arizona State University and University of Arkansas. http://www.sustainabilityconsortium.org/. accessed on September 25, 2012
- Sustainable Apparel Coalition (2012) [Online] http://www.apparelcoalition.org/. accessed on September 25, 2012
- UNEP/SETAC Life Cycle Initiative (2012) Greening the economy through life cycle thinking: ten years of the UNEP/SETAC Life Cycle Initiative. s.l.: United Nations Environment Programmme, 2012. ISBN 978-92-807-3268-9Google Scholar
- UNEP/SETAC Life Cycle Initiative (2010) http://lcinitiative.unep.fr/. accessed on September 25, 2012
- Water Footprint Network (2012) [Online]. http://www.waterfootprint.org/. accessed on September 25, 2012