Serenella Sala

Identifying best existing practice for characterization modeling in life cycle impact assessment

PurposeLife cycle impact assessment (LCIA) is a field of active development. The last decade has seen prolific publication of new impact assessment methods covering many different impact categories and providing characterization factors that often deviate from each other for the same substance and impact. The LCA standard ISO 14044 is rather general and unspecific in its requirements and offers little help to the LCA practitioner who needs to make a choice. With the aim to identify the best among existing characterization models and provide recommendations to the LCA practitioner, a study was performed for the Joint Research Centre of the European Commission (JRC).MethodsExisting LCIA methods were collected and their individual characterization models identified at both midpoint and endpoint levels and supplemented with other environmental models of potential use for LCIA. No new developments of characterization models or factors were done in the project. From a total of 156 models, 91 were short listed as possible candidates for a recommendation within their impact category. Criteria were developed for analyzing the models within each impact category. The criteria addressed both scientific qualities and stakeholder acceptance. The criteria were reviewed by external experts and stakeholders and applied in a comprehensive analysis of the short-listed characterization models (the total number of criteria varied between 35 and 50 per impact category). For each impact category, the analysis concluded with identification of the best among the existing characterization models. If the identified model was of sufficient quality, it was recommended by the JRC. Analysis and recommendation process involved hearing of both scientific experts and stakeholders.Results and recommendationsRecommendations were developed for 14 impact categories at midpoint level, and among these recommendations, three were classified as “satisfactory” while ten were “in need of some improvements” and one was so weak that it has “to be applied with caution.” For some of the impact categories, the classification of the recommended model varied with the type of substance. At endpoint level, recommendations were only found relevant for three impact categories. For the rest, the quality of the existing methods was too weak, and the methods that came out best in the analysis were classified as “interim,” i.e., not recommended by the JRC but suitable to provide an initial basis for further development.Discussion, conclusions, and outlookThe level of characterization modeling at midpoint level has improved considerably over the last decade and now also considers important aspects like geographical differentiation and combination of midpoint and endpoint characterization, although the latter is in clear need for further development. With the realization of the potential importance of geographical differentiation comes the need for characterization models that are able to produce characterization factors that are representative for different continents and still support aggregation of impact scores over the whole life cycle. For the impact categories human toxicity and ecotoxicity, we are now able to recommend a model, but the number of chemical substances in common use is so high that there is a need to address the substance data shortage and calculate characterization factors for many new substances. Another unresolved issue is the need for quantitative information about the uncertainties that accompany the characterization factors. This is still only adequately addressed for one or two impact categories at midpoint, and this should be a focus point in future research. The dynamic character of LCIA research means that what is best practice will change quickly in time. The characterization methods presented in this paper represent what was best practice in 2008–2009.

Ecological vulnerability in risk assessment — A review and perspectives

This paper reviews the application of ecological vulnerability analysis in risk assessment and describes new developments in methodology. For generic non-site-specific assessments (e.g. for the requirements of most European directives on dangerous chemicals) risk is characterised just on the basis of the ratio between an effect indicator and an exposure indicator. However, when the actual risk for a specific ecosystem is desired, the concept of ecological vulnerability may be more appropriate. This calls for a change in thinking, from sensitivity at the organism level to vulnerability at higher organization levels, and thus forms the link from laboratory toxicology to field effects at population, community or ecosystem level. To do so, biological and ecological characteristics of the ecosystems under concern are needed to estimate the ecological vulnerability. In this review we describe different vulnerability analysis methods developed for populations (of a single species), communities (consisting of different populations of species) and ecosystems (community and habitat combined). We also give some examples of methods developed for socio-ecological systems. Aspects that all methods share are the use of expert judgment, the input of stakeholders, ranking and mapping of the results, and the qualitative nature of the results. A new general framework is presented to guide future ecological vulnerability analysis. This framework can be used as part of ecological risk assessment, but also in risk management. We conclude that the further quantification of ecological vulnerability is a valuable contribution to vulnerability assessment.

Progress in sustainability science: lessons learnt from current methodologies for sustainability assessment: Part 1

PurposeSustainability Science (SS) is considered an emerging discipline, applicative and solution-oriented whose aim is to handle environmental, social and economic issues in light of cultural, historic and institutional perspectives. The challenges of the discipline are not only related to better identifying the problems affecting sustainability but to the actual transition towards solutions adopting an integrated, comprehensive and participatory approach. This requires the definition of a common scientific paradigm in which integration and interaction amongst sectorial disciplines is of paramount relevance. In this context, life cycle thinking (LCT) and, in particular, life cycle-based methodologies and life cycle sustainability assessment (LCSA) may play a crucial role. The paper illustrates the main challenges posed to sustainability assessment methodologies and related methods in terms of ontology, epistemology and methodology of SS. The aims of the analysis are twofold: (1) to identify the main features of methodologies for sustainability assessment and (2) to present key aspects for the development of robust and comprehensive sustainability assessment.MethodsThe current debate on SS addressing ontological, epistemological and methodological aspects has been reviewed, leading to the proposal of a conceptual framework for SS. In addition, a meta-review of recent studies on sustainability assessment methodologies and methods, focusing those life cycle based, supports the discussion on the main challenges for a comprehensive and robust approach to sustainability assessment. Starting from the results of the meta-review, we identified specific features of sustainable development-oriented methods: firstly, highlighting key issues towards robust methods for SS and, secondly, capitalising on the findings of each review’s paper. For each issue, a recommendation towards a robust sustainability assessment method is given. Existing limitations of sectorial academic inquiries and proposal for better integration and mainstreaming of SS are the key points under discussion.DiscussionIn the reviewed papers, LCT and its basic principles are acknowledged as relevant for sustainability assessment. Nevertheless, LCT is not considered as a reference approach in which other methods could also find a place. This aspect has to be further explored, addressing the lack of multi-disciplinary exchange and putting the mainstreaming of LCT as a priority on the agenda of both life cycle assessment and sustainability assessment experts. Crucial issues for further developing sustainability assessment methodologies and methods have been identified and can be summarised as follows: holistic and system wide approaches, shift from multi- towards trans-disciplinarity; multi-scale (temporal and geographical) perspectives; and better involvement and participation of stakeholders.ConclusionsThose are also the main challenges posed to LCSA in terms of progress of ontology, epistemology and methodology in line with the progress of SS. The life cycle-based methodologies should be broadened from comparing alternatives and avoiding negative impacts, to also proactively enhancing positive impacts, and towards the achievement of sustainability goals.

Assessing resource depletion in LCA: a review of methods and methodological issues

PurposePolitical interest in the future availability of natural resources has spiked recently, with new documents from the European Union, United Nations Environment Programme and the US National Research Council assessing the supply situation of key raw materials. As resource efficiency is considered a key element for sustainable development, suitable methods to address sustainability of resource use are increasingly needed. Life cycle thinking and assessment may play a principal role here. Nonetheless, the extent to which current life cycle impact assessment methods are capable to answer to resource sustainability challenges is widely debated. The aim of this paper is to present key elements of the ongoing discussion, contributing to the future development of more robust and comprehensive methods for evaluating resources in the life cycle assessment (LCA) context.MethodsWe systematically review current impact assessment methods dealing with resources, identifying areas of improvement. Three key issues for sustainability assessment of resources are examined: renewability, recyclability and criticality; this is complemented by a cross-comparison of methodological features and completeness of resource coverage.Results and discussionThe approach of LCA to resource depletion is characterised by a lack of consensus on methodology and on the relative ranking of resource depletion impacts as can be seen from a comparison of characterisation factors. The examined models yield vastly different characterisations of the impacts from resource depletion and show gaps in the number and types of resources covered.ConclusionsKey areas of improvement are identified and discussed. Firstly, biotic resources and their renewal rates have so far received relatively little regard within LCA; secondly, the debate on critical raw materials and the opportunity of introducing criticality within LCA is controversial and requires further effort for a conciliating vision and indicators. We identify points where current methods can be expanded to accommodate these issues and cover a wider range of natural resources.

Life cycle sustainability assessment in the context of sustainability science progress (part 2)

PurposeIn the context of progress of sustainability science, life cycle thinking and, in particular, life cycle sustainability assessment may play a crucial role. Environmental, economic and social implications of the whole supply chain of products, both goods and services, their use and waste management, i.e. their entire life cycle from “cradle to grave” have to be considered to achieve more sustainable production and consumption patterns. Progress toward sustainability requires enhancing the methodologies for integrated assessment and mainstreaming of life cycle thinking from product development to strategic policy support. Life cycle assessment (LCA), life cycle costing (LCC) and social LCA (sLCA) already attempt to cover sustainability pillars, notwithstanding different levels of methodological development. An increasing concern on how to deal with the complexity of sustainability has promoted the development of life cycle sustainability frameworks. As a contribution to the ongoing scientific debate after the Rio+20 conference, this paper aims to present and discuss the state of the art of life cycle sustainability assessment (LCSA), giving recommendations for its further development in line with ontological, epistemological and methodological aspects of sustainability science.MethodsBuilding on the review about the state of the art of sustainability science and sustainability assessment methods presented in part I, this paper discuss LCA, LCC, sLCA and LCSA against ontological, epistemological and methodological aspects of ongoing scientific debate on sustainability. Strengths and weaknesses of existing life cycle-based methodologies and methods are presented. Besides, existing frameworks for LCSA are evaluated against the criteria defined in part I in order to highlight coherence with sustainability science progress and to support better integration and mainstreaming of sustainability concepts.Conclusions and outlookLCSA represents a promising approach for developing a transparent, robust and comprehensive assessment. Nevertheless, the ongoing developments should be in line with the most advanced scientific discussion on sustainability science, attempting to bridge the gaps between the current methods and methodologies for sustainability assessment. LCSA should develop so as to be hierarchically different from LCA, LCC and sLCA. It should represent the holistic approach which integrates (and not substitutes) the reductionist approach of the single part of the analysis. This implies maintaining the balance between analytical and descriptive approaches towards a goal and solution-oriented decision support methodology.

Rethinking the Area of Protection “Natural Resources” in Life Cycle Assessment

Life cycle impact assessment (LCIA) in classical life cycle assessment (LCA) aims at analyzing potential impacts of products and services typically on three so-called areas of protection (AoPs): Natural Environment, Human Health, and Natural Resources. This paper proposes an elaboration of the AoP Natural Resources. It starts with analyzing different perspectives on Natural Resources as they are somehow sandwiched in between the Natural Environment (their cradle) and the human-industrial environment (their application). Reflecting different viewpoints, five perspectives are developed with the suggestion to select three in function of classical LCA. They result in three safeguard subjects: the Asset of Natural Resources, their Provisioning Capacity, and their role in Global Functions. Whereas the Provisioning Capacity is fully in function of humans, the global functions go beyond provisioning as they include nonprovisioning functions for humans and regulating and maintenance services for the globe as a whole, following the ecosystem services framework. A fourth and fifth safeguard subject has been identified: recognizing the role Natural Resources for human welfare, either specifically as building block in supply chains of products and services as such, either with or without their functions beyond provisioning. But as these are far broader as they in principle should include characterization of mechanisms within the human industrial society, they are considered as subjects for an integrated sustainability assessment (LCSA: life cycle sustainability assessment), that is, incorporating social, economic and environmental issues.

Ecological vulnerability analysis: A river basin case study

Assessing and quantifying ecosystem vulnerability is a key issue in site-specific ecotoxicological risk assessment. In this paper, the concept of vulnerability, particularly referred to aquatic ecosystems is defined. Sensitivity to stressors, susceptibility for exposure and recovery capability are described as component of vulnerability of biological communities. The potential for habitat changes must also be considered in ecosystem vulnerability assessment. A procedure based on the application of an ecosystem vulnerability index is proposed. The method allows the assessment of vulnerability of riverine ecosystems to multiple stressors. The procedure is applied to two river systems in northern Italy: River Serio, subject to strong human pressure, and River Trebbia, in semi-natural conditions, as reference system. Macrozoobenthos is chosen as the indicator community. The actual quality of River Serio was evaluated as the result of the multiple stressor pressure on the reference system. Values and limitations of the approach are discussed.

Normalisation and weighting in life cycle assessment: quo vadis?

PurposeBuilding on the rhetoric question “quo vadis?” (literally “Where are you going?”), this article critically investigates the state of the art of normalisation and weighting approaches within life cycle assessment. It aims at identifying purposes, current practises, pros and cons, as well as research gaps in normalisation and weighting. Based on this information, the article wants to provide guidance to developers and practitioners. The underlying work was conducted under the umbrella of the UNEP-SETAC Life Cycle Initiative, Task Force on Cross-Cutting issues in life cycle impact assessment (LCIA).MethodsThe empirical work consisted in (i) an online survey to investigate the perception of the LCA community regarding the scientific quality and current practice concerning normalisation and weighting; (ii) a classification followed by systematic expert-based assessment of existing methods for normalisation and weighting according to a set of five criteria: scientific robustness, documentation, coverage, uncertainty and complexity.Results and discussionThe survey results showed that normalised results and weighting scores are perceived as relevant for decision-making, but further development is needed to improve uncertainty and robustness. The classification and systematic assessment of methods allowed for the identification of specific advantages and limitations.ConclusionsBased on the results, recommendations are provided to practitioners that desire to apply normalisation and weighting as well as to developers of the underlying methods.

Beyond the throwaway society: A life cycle‐based assessment of the environmental benefit of reuse

In the context of a circular economy, sustainable consumption is often seen as the antithesis of current consumption patterns, which have led to the definition of the so-called throwaway society. Reuse may provide a preferred alternative to other waste management options, because it promotes resource efficiency and may significantly reduce environmental impacts. To appraise the environmental benefits related to reuse of goods, a methodology adopting life cycle assessment (LCA) has been developed. A standardized procedure has been developed, identifying reference products within product category subject to reuse, and collecting reliable inventory data as a basis for calculating environmental impact through LCA. A case study on a second-hand shop is presented, and the avoided impacts are quantified. Inventory data were taken both from the literature and directly from sales and surveys submitted to customers. The results are presented, highlighting: 1) for each product category, the average avoided impacts for 1 unit of reused product considered; and 2) for the overall activities of the second-hand shop, the cumulative avoided impacts in 1 yr. In the case study, the higher contribution to avoided impacts comes from the apparel sector, due to the high amount of items sold, followed by the furniture sector, because of the high amount of environmental impacts avoided by the reuse of each single item.

Making sense of the minefield of footprint indicators.

Bradley Ridoutt,*,† Peter Fantke,‡ Stephan Pfister, Jane Bare, Anne-Marie Boulay, Francesco Cherubini, Rolf Frischknecht, Michael Hauschild,‡ Stefanie Hellweg, Andrew Henderson, Olivier Jolliet, Annie Levasseur, Manuele Margni, Thomas McKone, Ottar Michelsen, Llorenc Mila i Canals, Girija Page, Rana Pant, Marco Raugei, Serenella Sala, Erwan Saouter, Francesca Verones, and Thomas Wiedmann †Commonwealth Scientific and Industrial Research Organisation (CSIRO), Clayton, Victoria 3169, Australia ‡Technical University of Denmark (DTU), Department for Management Engineering, Division for Quantitative Sustainability Assessment, 2800 Kgs. Lyngby, Denmark ETH Zurich, Institute of Environmental Engineering, 8093 Zurich, Switzerland United States Environmental Protection Agency, Sustainable Technology Division, Systems Analysis Branch, National Risk Management Research Laboratory, Cincinnati, Ohio 45268, United States CIRAIG, Ecole Polytechnique de Montreal, Montreal, Canada Norwegian University of Science and Technology (NTNU), Industrial Ecology Programme, Department of Energy and Process Engineering, NO-7491 Trondheim, Norway treeze Ltd., Uster, Switzerland University of Texas Health Science Center, School of Public Health, Division of Epidemiology, Human Genetics and Environmental Sciences, Houston, Texas 77030, United States University of Michigan, School of Public Health, Environmental Health Sciences, Ann Arbor, Michigan 48109, United States University of California, Lawrence Berkeley National Laboratory and School of Public Health, Berkeley, California 94720, United States Norwegian University of Science and Technology (NTNU), Division for Finance and Property, NO-7491 Trondheim, Norway United Nations Environment Programme (UNEP), Division for Technology, Industry and Economics, 15 Rue de Milan, 75009 Paris, France University of Western Sydney, School of Science and Health, Penrith, NSW 2751, Australia European Commission, Joint Research Centre, Institute for Environment and Sustainability, Via Enrico Fermi 2749, Ispra, I-21027, Italy Oxford Brookes University, Department of Mechanical Engineering and Mathematical Sciences, Oxford OX33 1HX, United Kingdom UNSW Australia, Sustainability Assessment Program, School of Civil and Environmental Engineering, Sydney, NSW 2052, Australia