JIE Dissertation Listing

Author: Patrick Hofstetter
Title: Perspectives in Life Cycle Impact Assessment a Structured Approach to Combine Models of the Technosphere, Ecosphere and Valuesphere
Institution: ETH Zurich (Swiss Federal Institute of Technology)
Date: August 1998
Advisor: Prof. Roland W. Scholz, Prof. Dr. P. Suter
Key Words: Life Cycle Assessment, impact assessment, Cultural Theory, damage assessment, unknown damage, manageability, carcinogenic effects, respiratory effects, graphical dominance analysis
How to Obtain: (Kluwer Academic Publishers, Boston) http://www.wkap.nl/book.htm/0-7923-8377-X
 Abstract: Environmental Life Cycle Assessment (LCA) is a tool used to compare the environmental impacts along the life cycle of products. It thus supports the design of products which cause less harm to the environment. ISO distinguishes between four phases within LCA: the goal and scope definition, the inventory analysis, the impact assessment (LCIA), and the interpretation. The impact assessment phase as well as some aspects of the interpretation phase are the subject of this book.  LCA is a young tool which is still under development. In the course of its international standardisation ,two main problems have been identified: (1) LCA is full of subjectivity and does not properly separate objective from subjective elements, and (2) the impact assessment records phantoms rather than actual damages. This book suggests a new framework for LCA designed to master these two problems.

The new structure represents a radical departure from past attempts in LCA methodology development to distinguish clearly between so-called objective and subjective elements and to assign them to distinct process phases. It builds instead on the acceptance of the view that LCA is the art of modelling and combineing the valuesphere, the ecosphere, and the technosphere. This basic structure is then particularised with the use and combination of elements developed independently in many different research fields in the natural, social, and medical sciences. The book's focus is on problems rather than disciplinary research questions that highlights the interface between natural and social sciences. The careful review and combination of these existing elements in the new structure results in a partly operationalised framework organised around a number of hypotheses. These have a high level of explanatory power for past developments and new trends and seem to offer a fruitful base for further validation.  The book offers concrete and pragmatic operationalisations of many of the hypotheses demonstrating that a consistent realisation of the framework is feasible in principle even though central elements remain in the status of hypotheses. The following elements are fully worked out  in this book: 

  • The valuesphere is explicitly accepted as a sphere of its own and not seen as making up the undesired subjective elements which somehow have to be circumvented. The valuesphere therefore has to be modelled as such. An evaluation of models which characterise societal groups and their world views revealed that Cultural Theory serves well to model the valuesphere. Cultural Theory claims: (i) that people can be classified according to the degree that they organise themselves in groups and the degree to which individual lives are circumscribed by externally imposed prescriptions; (ii) that cultural biases can be understood as shared values and beliefs; and (iii) that there are five viable ways of life which combine different social relations and cultural biases. This theory serves to model value choices inherent in LCA in a way that is compatible with the values and beliefs of archetypes identified as viable ways of life. Only three of the five archetypes (hierarchists, individualists, and egalitarians) are considered because they are the only ones that actively take part in decision making. Consequently, this book offers not just one but three assessment systems. Each one is compatible with one of three active perspectives.
  • The ecosphere is modelled by three submodels: a model for the known damage, a model for the unknown damage, and a model for the manageability of the damage.
    • The model of the known damage includes causal effects by environmental interventions on safeguard subjects representing the environment. The model is operationalised for carcinogenic and respiratory effects in human beings and includes fate, exposure, effect, and damage analyses for a selection of more than 150 substances contributing to these effects. Damage to human health is measured in terms of disability adjusted life years (DALYs), a unit that is already used internationally and which is adapted here for use in LCA. The best estimate for the steady-state health damages in Europe due to actual emissions of carcinogenic substances resulted in a share of about 3% compared to all health damages (including all risk factors) and is dominated by the heavy metals and persistent organics. The same share for substances causing respiratory effects is estimated to be about 6% and is fully dominated by primary and secondary particles.
    • The model of the unknown damage acknowledges that little is known so far on causal relationships in a system which is best characterised as overcomplex. The proxy index combines bioconcentration factors and world-wide emissions in order to consider the accumulating behaviour of, and the relative knowledge that is available on, a substance.
    • The manageability of damage considers the dynamic aspects of the damages and is quantified by indicators for the ease of damage reduction, the excess of target damage, and the success of regulation.
  • The combination of the three spheres is relatively easy because the outcome of the inventory analysis, i.e., the model of the technosphere, is already well known and presented in so-called inventory tables which are the direct input for the three submodels of the ecosphere. The ecosphere's submodels are chosen in such a way that their outcomes fulfil the requirements from all those archetypes considered to be active decision makers and that are characterised in the valuesphere. The interface between the valuesphere and the technosphere is described on the basis of two examples.
  • A graphical dominance analysis is presented in order to improve the interpretation of the modelling results. Decisive rankings between alternatives can be made thanks to this new tool with as little weighting as necessary. This avoids the need to offer in all cases a full aggregation with a fixed weighting set which is the direction taken by several proposals to valuate environmental impacts in LCA. 
This ambitious framework for LCA is partly operationalised and partly complemented with suggestions for a pragmatic operationalisation of those elements left inoperable. The framework is open for adjustments and the elements can be made operable by use of adequate models from the different disciplines concerned. A fourfold meaning of perspectives is worked out in this book: the LCA perspective of the world addressing the life-cycle view and its implications; the perspective of understanding LCA as a model of three spheres; the cultural perspectives leading to models that depend on world views; and finally the perspective of future developments supported by the openness of the framework.