Survey Insights into Weighting Environmental Damages: Influence of Context and Group

661

303

Background, aims, and scope Life cycle assessment (LCA) stands as the pre-eminent tool for estimating environmental effects caused by products and processes from 'cradle to grave' or 'cradle to cradle.' It exists in multiple forms, claims a growing list of practitioners and remains a focus of continuing research. Despite its popularity and codification by organizations such as the International Organization for Standardization and the Society of Environmental Toxicology and Chemistry, life cycle assessment is a tool in need of improvement. Multiple authors have written about its individual problems, but a unified treatment of the subject is lacking. The following literature survey gathers and explains issues, problems and problematic decisions currently limiting LCA's impact assessment and interpretation phases. Main features The review identifies 15 major problem areas and organizes them by the LCA phases in which each appears. This part of the review focuses on the latter eight problems. It is meant as a concise summary for practitioners interested in methodological limitations which might degrade the accuracy of their assessments. For new researchers, it provides an overview of pertinent problem areas toward which they might wish to direct their research efforts. Having identified and discussed LCA's major problems, closing sections highlight the most critical problems and briefly propose research agendas meant to improve them. Results and discussion Multiple problems occur in each of LCA's four phases and reduce the accuracy of this tool. Considering problem severity and the adequacy of current solutions, six of the 15 discussed problems are of paramount importance. In LCA's latter two phases, spatial variation and local environmental uniqueness are critical problems requiring particular attention. Data availability and quality are identified as critical problems affecting all four phases. Conclusions and recommendations Observing that significant efforts by multiple researchers have not resulted in a single, agreed upon approach for the first three critical problems, development of LCA archetypes for functional unit definition, boundary selection and allocation is proposed. Further development of spatially explicit, dynamic modeling is recommended to ameliorate the problems of spatial variation and local environmental uniqueness. Finally, this paper echoes calls for peer-reviewed, standardized LCA inventory and impact databases, and it suggests the development of model bases. Both of these efforts would help alleviate persistent problems with data availability and quality.

Section: Problems In Other Weighting Methodsmentioning

confidence: 99%

Section: Problems In Other Weighting Methodsmentioning

confidence: 99%

A survey of unresolved problems in life cycle assessment

Reap,

Roman,

Duncan

et al. 2008

661

303

“…In fundamental evaluation discussions, we ideally would link environmental effects to values. Hofstetter (1998) has been one of the early contributors to the discussion, showing how preferences differ between cultural perspectives, attitudes, and stakeholders, see also Mettier and Hofstetter (2005). Divergent approaches were coming up then already (see Notarnicola et al 1998).…”

Section: Introductionmentioning

confidence: 99%

Weighting environmental effects: Analytic survey with operational evaluation methods and a meta-method

Huppes

Oers

Pretato

et al. 2012

Purpose The purpose of this paper is to supply an open method for weighting different environmental impacts, open to basically different evaluation approaches and open to easy revisions. From the partial, diverse and conflicting weighing methods available, a most consistent and flexible meta-method is constructed, allowing for a transparent discussion on weighting. Methods The methods incorporated are as general as possible, each single one being as pure as possible. We surveyed encompassing operational methods for evaluation, applicable in LCA and in larger systems like countries. They differ in terms of modelling, as to midpoint or as to endpoint; as to evaluation set-up, in terms of collective preferences or individual preferences; and as to being either revealed or stated. The first is midpoint modelling with collectively stated preferences, with operational weighting schemes from Dutch and US government applications. Second is the LCAtype endpoint approach using individual stated preferences, with public examples from Japan and the Netherlands. The third is the integrated modelling approach by economists.Results All methods are internally inconsistent, as in terms of treatment of place and time, and they are incomplete, lacking environmental interventions and effect routes. We repaired only incompleteness, by methods transfer. Finally, we combined the three groups of methods into a metaweighting method, aligned to the ILCD Handbook requirements for impact assessment. Application to time series data on EU-27 consumption shows how the EU developed in terms of overall environmental decoupling. Conclusions The disparate methods available all can be improved substantially. For now, a user adjustable metamethod is the best option, allowing for public discussion. A flexible regularly updated spreadsheet is supplied with the article.

“…Choice-based methods pool data across all individuals and, as such, do not obtain estimates at the individual level. Therefore, studies involving different value positions, e.g., value characterization according to cultural theory (Mettier and Hofstetter 2004) or according to sustainability perspectives (Steen 2005), are harder to run as they need bigger samples. That means it is harder to handle value plurality in choicebased procedures.…”

Section: Discussionmentioning

confidence: 99%

“…The weighting factors are finally calculated based on these relative scores, e.g., in the analytical hierarchy process (AHP) (Saaty 1980). Such methods have been used by Puolamaa et al (1996), Sangle et al (1999), Seppälä (1999), Harada et al (2000), and Mettier and Hofstetter (2004). Methods for the monetary valuation of environmental goods, 1 such as contingent valuation or conjoint choice experiments (see Section 2.1) are often based on choice questions.…”

mentioning

confidence: 99%

Measuring preferences on environmental damages in LCIA. Part 2: choice and allocation questions in panel methods

Mettier

Scholz

2008

Background, aim, and scope Within life cycle impact assessment (LCIA), 'panel methods' has become a common term to denominate methods that elicit and measure stakeholders' stated preferences on environmental impact categories. Such panel procedures use different question formats to elicit information on weighting across impact categories from the stakeholders. The two most frequently used question formats are score allocation and choice between alternatives. The differences between these two question formats were analyzed in order to give advice on how to frame future panel procedures. Materials and methods A choice-based weighting procedure (choice experiment) for the three damage categories of human health, ecosystems quality, and resources was developed and executed. A logistic regression model was applied in order to estimate the weighting factors for the polled sample. Results from this choice-based procedure were compared to the results from an allocation-based procedure described in part 1 of this paper. Results When weighting factors are elicited by score allocation questions, panelists tend to distribute the scores more equally. A factor of 1.5 between the least and the most weighted damage category was found. Weighting factors from a choice experiment were more spread, i.e., the most important category was weighted considerably higher, whereas the other two categories were weighted less. Thus, for the choice experiment, the range between the most and the least weighted categories was considerably bigger-by about a factor of 4. Discussion A comparison of the two procedures revealed that the weighting of environmental damage categories is considerably influenced by the question of format. The reason for these variations may be different cognitive routines that are applied. In addition, several advantages and shortcomings of choice experiments are discussed. Conclusions The developed, choice-based procedure provided meaningful results. Thus, choice experiments, often used for the monetary valuation of environmental goods, can also be applied in LCIA to elicit nonmonetary weighting factors. Recommendations and perspectives Choice experiments form a new interesting approach for weighting procedures in the future as they have some advantages over the often used score allocation methods. They are simple and more realistic than other procedures, as panelists have practiced in choice tasks from everyday life. We, therefore, recommend such choice-based procedures for future panel studies.Keywords Choice experiments . Framing . Panel surveys . Stated preference . Weighting of damage categories in LCIA 1 Background, aim, and scopeIn general, life cycle impact assessment (LCIA) finishes up with a set of three to 12 impact category indicator results that describe the impact of a product system on the environment. Weighting across impact categories is often needed in order to interpret these category indicator results and to draw conclusions. Within LCIA, 'panel methods' Int J Life Cycle Assess (2008) 13:468-476