Helias A. Udo de Haes

Midpoints versus endpoints: The sacrifices and benefits

On May 25–26, 2000 in Brighton (England), the third in a series of international workshops was held under the umbrella of UNEP addressing issues in Life Cycle Impact Assessment (LCIA). The workshop provided a forum for experts to discuss midpoint vs. endpoint modeling. Midpoints are considered to be links in the cause-effect chain (environmental mechanism) of an impact category, prior to the endpoints, at which characterization factors or indicators can be derived to reflect the relative importance of emissions or extractions. Common examples of midpoint characterization factors include ozone depletion potentials, global warming potentials, and photochemical ozone (smog) creation potentials. Recently, however, some methodologies have adopted characterization factors at an endpoint level in the cause-effect chain for all categories of impact (e.g., human health impacts in terms of disability adjusted life years for carcinogenicity, climate change, ozone depletion, photochemical ozone creation; or impacts in terms of changes in biodiversity, etc.). The topics addressed at this workshop included the implications of midpoint versus endpoint indicators with respect to uncertainty (parameter, model and scenario), transparency and the ability to subsequently resolve trade-offs across impact categories using weighting techniques. The workshop closed with a consensus that both midpoint and endpoint methodologies provide useful information to the decision maker, prompting the call for tools that include both in a consistent framework.

The LCIA midpoint-damage framework of the UNEP/SETAC life cycle initiative

Background, Aims and ScopeLife Cycle Impact Assessment (LCIA) methods can be grouped into two families: classical methods determining impact category indicators at an intermediate position of the impact pathways (e.g. ozone depletion potentials) and damage-oriented methods aiming at more easily interpretable results in the form of damage indicators at the level of the ultimate societal concern (e.g. human health damage). The Life Cycle Initiative, a joint project between UNEP1 and SETAC2, proposes a comprehensive LCA framework to combine these families of methods. The new framework takes a world-wide perspective, so that LCA will progress towards a tool meeting the needs of both developing and developed countries. By a more precise and broadly agreed description of main framework elements, the Life Cycle Initiative expects to provide a common basis for the further development of mutually consistent impact assessment methods.Main FeaturesInputs to the LCIA midpoint-damage framework are results of Life Cycle Inventory analyses (LCI). Impact pathways connect the LCI results to the midpoint impact categories with the corresponding indicators, as well as to the damage categories at the level of damages to human health, natural environment, natural resources and man-made environment, via damage indicators. Mid-point impact categories simplify the quantification of these impact pathways where various types of emissions or extractions can be aggregated due to their comparable impact mechanisms. Depending on the available scientific information, impact pathways may be further described up to the level of damage categories by quantitative models, observed pathways or merely by qualitative statements. In the latter case, quantitative modelling may stop at mid-point. A given type of emission may exert damaging effects on multiple damage categories, so that a corresponding number of impact pathways is required. Correspondingly, a given damage category may be affected jointly by various types of emissions or extractions. It is therefore an important task of the Life Cycle Initiative to carefully select damage indicators. The content of the midpoint and of the damage categories is clearly defined, and proposals are made on how to express the extent of environmental damage by suitable indicator quantities.Conclusions and OutlookThe present framework will offer the practitioner the choice to use either midpoint or damage indicators, depending on modelling uncertainty and increase in results interpretability. Due to the collaboration of acknowledged specialists in environmental processes and LCIA around the globe, it is expected that - after a few years of effort - the task forces of the Life Cycle Initiative will provide consistent and operational sets of methods and factors for LCIA in the future.

Analytical tools for environmental design and management in a systems perspective

Preface. Foreword. Part I: Demand and supply of environmental information. 1. Introduction. 2. Demands for environmental information. 3. Supply of environmental information for decision support. 4. Analytical tools. 5. Linking supply and demand concerning environmental information. 6. Concluding remarks. References. Part II: Cases and Appendices. A. Case Study: The supply, use and waste management chain of electronic consumer goods. B. Case Study: Towards reduced environmental burden of mobility: improving the automobile life cycle. C. Case Study: The supply, use and waste management of domestic clothes washing. D. Full description of tools. E. Inquiry on user preferences concerning analytical tools for environmental evaluation. F. List of definitions. G. Acronyms and abbreviations.

Quantitative life cycle assessment of products. 2. Classification, valuation and improvement analysis

In a previous article about life cycle assessment (LCA), a methodological framework was proposed and two components of this framework were discussed in more detail: the goal definition and the inventory. In this second article, the other components of the framework are discussed in detail: the classification, the valuation and the improvement analysis. In the classification, resource extractions and emissions associated with the life cycle of a product are translated into contributions to a number of environmental problem types, such as resource depletion, global warming, ozone depletion, acidification, etc. For this, each extraction and emission is multiplied with a so-called classification factor and the multiplication results are aggregated per problem type. Classification factors are proposed for a number of environmental problem types. The valuation includes both a valuation of the different environmental problem types and an assessment of the reliability and validity of the results. For the valuation of the environmental problem types, qualitative or quantitative multicriterion analysis could be applied. Given a standard list of weighting factors the quantitative multicriterion analysis seems preferable, because of its low costs and its simplicity. The main problem, however, is to get a broadly supported standard list. In studies so far little attention is paid to the assessment of the reliability and the validity of the results. To improve this situation methods which could support this assessment are proposed. In the improvement analysis potential options to improve the product(s) studied are identified. Combined with expertise in other fields, such as costs and technological feasibility, the improvement analysis may yield a number of serious options for the redesign of a product. Two complementary techniques for the identification of the potential options are discussed. With these techniques and the active participation of process technologists and designers, LCA might become an analytic tool for eco-design supporting a continuous environmental improvement of products.

Guidelines for ecological compensation associated with highways

Abstract Avoidance, mitigation and compensation are three planning concepts designed to counteract the adverse impacts of infrastructure on nature. To promote the compensation principle introduced in the Netherlands, this article proposes guidelines for its implementation in the context of highway development. To this end, a coherent framework has been developed comprising: (1) impacts on nature, (2) concepts for use in planning ecological compensation, and (3) ecological, spatial-planning and financial instruments for realizing such compensation. Finally, the Dutch experience is discussed within the international context. Recommendations are made for improving the implementation of compensation. These stress the importance of creating ‘win–win’ situations to increase public support, of dealing with impacts that cannot be predicted, and of developing criteria for evaluating compensation plans. There are still several priority problems to be dealt with: the effects of habitat isolation caused by highway projects, the effectiveness of compensation measures and compensation ratios (viz. ratios of replacement to lost area) greater than one, the real costs associated with replacing habitats, the feasibility of compensation for ecological values that are difficult to replace, and the strategy to exchange impacted and substitute habitats.

Life cycle impact assessment sophistication

On November 29 – 30, 1998 in Brussels, an international workshop was held to discuss Life Cycle Impact Assessment (LCIA) Sophistication. Approximately 50 LCA experts attended the workshop from North America, Europe, and Asia. Prominent practitioners and researchers were invited to present a critical review of the associated factors, including the current limitations of available impact assessment methodologies and a comparison of the alternatives in the context of uncertainty. Each set of presentations, organised into three sessions, was followed by a discussion session to encourage international discourse with a view to improving the understanding of these crucial issues. The discussions were focused around small working groups of LCA practitioners and researchers, selected to include a balance of representatives from industry, government and academia.This workshop provided the first opportunity for International experts to address the issues related to LCIA Sophistication in an open format. Among the topics addressed were: 1) the inclusion or exclusion of backgrounds and thresholds in LCIA, 2) the necessity and practicality regarding the sophistication of the uncertainty analysis, 3) the implications of allowing impact categories to be assessed at “midpoint” vs. at “endpoint” level, 4) the difficulty of assessing and capturing the comprehensiveness of the environmental health impact category, 5) the implications of cultural/philosophical views, 6) the meaning of terms like science-based and environmental relevance in the coming ISO LCIA standard, 7) the dichotomy of striving for consistency while allowing the incorporation of state-of-the-art research, 8) the role of various types of uncertainty analysis, and 9) the role of supporting environmental analyses (e.g., risk assessments). Many of these topics addressed the need for increased sophistication in LCIA, but recognised the conflict this might have in terms of the comprehensiveness and holistic character of LCA, and LCIA in particular. The participants concluded that the exchange of ideas in this format was extremely valuable and would like to plan successive International workshops on related themes.

Applications of life cycle assessment: expectations, drawbacks and perspectives

Abstract In this article an overview is given of present applications of life cycle assessment (LCA) as an instrument for the support of decision-making. Attention is given to original expectations, present drawbacks and future perspectives. The following dimensions are chosen for this overview: the main users, with a distinction between governments, companies and non-governmental organizations; the level of sophistication, distinguishing between LCA as a concept, qualitative LCA and quantitative LCA, with varying degrees of detail within the latter; a distinction between applications at an operational and at a strategic level; a distinction between internal and external applications; and finally the level of completeness of the study, i.e. which limitations are set a priori for a study. Three types of drawbacks are encountered: purely technical problems, methodological problems and communication problems. Possible ways to cope with these are discussed.

Nitrogen pollution in the European Union – origins and proposed solutions

The European Union is faced with major environmental problems related to nitrogen (N) compounds. The origins of three such problems, the atmospheric deposition of N compounds, the leaching of nitrates to ground-water and the anthropogenic N-input to the North Sea, are investigated by means of a Substance Flow Analysis (SFA); the reference year is 1988. Although the problems occur at various scales and have varying direct causes, food production and consumption together are the main responsible sectors, and the production and import of fertilizer appear to be the major ultimate sources in all three cases. Measures to combat these problems have been agreed to in various international frameworks: the European Community, the International North Sea Conference and the Rhine States Conference. These measures include technical emission reduction for acidifying compounds resulting in a 30% emission reduction; extension of the sewage treatment network and application of denitrification with 50% effectiveness; and introduction of measures directed at efficiency increase and emission reduction in agricultural practice in 10% of the agricultural area. The recent changes in the Common Agricultural Policy (CAP) are not expected to lead to significant changes in N flows. Assuming full implementation, an almost sufficient 45% reduction is expected for the anthropogenic nitrogen input into the North Sea. The atmospheric deposition of nitrogen compounds will be reduced by approximately 20%. The leaching of nitrates to the ground-water is expected to remain at the current level or even to increase a little. In all, these measures are conducive to solving, but do not satisfactorily solve, the three problems, mainly because the ultimate origins of the problems are not sufficiently influenced and measures therefore inevitably result in a shifting of problems.

Similarities, Differences and Synergisms Between HERA and LCA—An Analysis at Three Levels

ABSTRACT Linkages between Human and Environmental Risk Assessment (HERA) and Life-Cycle Assessment (LCA) can be analyzed at three levels: the basic equations to describe environmental behavior and dose-response relationships of chemicals; the overall model structure of these tools; and the applications of the tools. At level 1 few differences exist: both tools use essentially the same fate and effect models, including their coefficients and data. At level 2 distinctive differences emerge: regional or life-cycle perspective, emission pulses or fluxes, scope of chemicals and types of impacts, use of characterization factors, spatial and temporal detail, aggregation of effects, and the functional unit as basis of the assessment. Although the two tools typically differ in all these aspects, only the functional unit issue renders the tools fundamentally different, expressing itself also in some main characteristics of the modeling structure. This impedes full integration, which is underpinned in mathematical terms. At level 3 the aims of the tools are complementary: quantified risk estimates of chemicals for HERA versus quantified product assessment for LCA. Here, beneficial synergism is possible between the two tools, as illustrated by some cases. These also illustrate that where full integration is suggested, in practice this is not achieved, thus in fact supporting the conclusions.

Using SFA indicators to support environmental policy

In order to improve the link from Substance Flow Analysis (SFA) studies to environmental policy, a translation is made from the SFA overview of flows and stocks into a limited set of indicators. This set is designed to evaluate a region’s substance regime with regard to environmental quality and sustainable development, including problem shifting in time and space.