Life‐Cycle Assessment: Constraints on Moving from Inventory to Impact Assessment

Abstract

Summary Life‐cycle assessment (LCA) is a technique for systematically analyzing a product from cradle‐to‐grave, that is, from resource extraction through manufacture and use to disposal. LCA is a mixed or hybrid analytical system. An inventory phase analyzes system inputs of energy and materials along with outputs of emissions and wastes throughout life cycle, usually as quantitative mass loadings. An impact assessment phase then examines these loadings in light of potential environmental issues using a mixed spectrum of qualitative and quantitative methods. The constraints imposed by inventory's loss of spatial, temporal, dose‐response, and threshold information raise concerns about the accuracy of impact assessment. The degree of constraint varies widely according to the environmental issue in question and models used to extrapolate the inventory data. LCA results may have limited value in two areas: (I) local and/ortransient biophysical processes and (2) issues involving biological parameters, such as biodiversity, habitat alteration, and toxicity. The end result is that impact assessment does not measure actual effects or impacts, nor does it calculate the likelihood of an effect or risk Rather, LCA impact assessment results are largely directional environmental indicaton. The accuracy and usefulness of indicators need to be assessed individually and in a circumstance‐specific manner prior to decision making. This limits LCAs usefulness as the sole basis for comprehensive assessments and the comparisons of alternatives. In conclusion, LCA may identify potential issues from a systemwide perspective, but more‐focused assessments using other analytical techniques are often necessary to resolve the issues.

Uncertainty and variability in environmental life-cycle assessment

“…From this perspective it is expected that the results of USES-LCA are more realistic than the results of USES 1.0. However, as long as validation of multi-media fate model results is practically impossible (Ragas et al, 1999), and toxicity potentials are not based on actual risks (Owens, 1997), fundamental uncertainties are large in USES-LCA. This should be subject of further research.…”

“…Aggregation may also be established with the concept of Disability Adjusted Life Years (DALYs), as described in detail by Hofstetter (1998). Other limitations concerning the application of toxicity potentials, such as the assumption of linearity between emissions and potential effects (Owens, 1997) and disregarding interactions between substances, are far more difficult…”

First International Conference on Resource Efficiency in Interorganizational Networks – ResEff 2013 –

“…Sensitivity models as a scientific method have been developed by Frederic Vester in his research group and have been tested out in several applications (see Harrer, 2011, malik management, 2012, Vester, 1990/1995/1997. For easier use of this method a software tool had been developed.…”

“…Therefore, the main concept of LCA is to provide a screening approach using mass loadings which enables the overall material and energy usage of a system to be assessed, which helps to identify all relevant burdens across the whole life cycle of a product or a process. In this way identifying where a shift of burdens from one process step to another may occur (Azapagic, 1999, Owens, 1997. However, regionalized energy concepts provide an opportunity to explore and include greater spatial aspects within the LCA tool; due to the more "regionalised" interlinkages in supply chains.…”

Industrial Ecology in Policy Making: What is Achievable and What is Not?

“…This implies that the impact rises linearly with the amount of product manufactured. Such a calculation ignores for example, that many harmful substances have limits that, if exceeded, make them dangerous, which is a nonlinear effect (Owens, 1997). Thirdly, a complete cradleto-grave analysis is usually not feasible for complex products, which are sometimes composed of thousands of parts.…”