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

Purpose

Political 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.

Methods

We 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 discussion

The 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.

Conclusions

Key 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.     

Impact assessment of abiotic resource consumption conceptual considerations

The impact assessment of the consumption of abiotic resources, such as fossil fuels or minerals, is usually part of the Life Cycle Impact Assessment (LCIA) in LCA studies. The problem with the consumption of such resources is their decreasing availability for future generations. In currently available LCA methods (e.g. Eco-indicator’ 99/Goedkoop and Spriensma 1999, CML/Guinée 2001), the consumption of various abiotic resources is aggregated into one summarizing indicator within the characterization phase of the LCIA. This neglects that many resources are used for different purposes and are not equivalent to each other. Therefore, the depletion of reserves of functionally non-equivalent resources should be treated as separate environmental problems, i.e. as separate impact sub-categories. Consequently, this study proposes assigning the consumption of abiotic resources to separate impact sub-categories and, if possible, integrating them into indicators only according to their primary function (e.g. coal, natural gas, oil → consumption of fossil fuels; phosphate rock → consumption of phosphate). Since this approach has been developed in the context of LCA studies on agricultural production systems, the impact assessment of the consumption of fossil fuels, phosphate rock, potash salt and lime is of particular interest and serves as an example. Following the general LCA framework (Consoli et al. 1993, ISO 1998), a normalization step is proposed separately for each of the subcategories. Finally, specific weighting factors have been calculated for the sub-categories based on the ’distance-to-target’ principle. The weighting step allows for further interpretation and enables the aggregation of the consumption of different abiotic resources to one summarizing indicator, called the Resource Depletion Index (RDI). The proposed method has been applied to a wheat production system in order to illustrate the conceptual considerations and to compare the approach to an established impact assessment method for abiotic resources (CML method, Guinée 2001).     

The economic resource scarcity potential (ESP) for evaluating resource use based on life cycle assessment

Purpose

In life cycle assessment (LCA), resource availability is currently evaluated by means of models based on depletion time, surplus energy, etc. Economic aspects influencing the security of supply and affecting availability of resources for human use are neglected. The aim of this work is the development of a new model for the assessment of resource provision capability from an economic angle, complementing existing LCA models. The inclusion of criteria affecting the economic system enables an identification of potential supply risks associated with resource use. In step with actual practice, such an assessment provides added value compared to conventional (environmental) resource assessment within LCA. Analysis of resource availability including economic information is of major importance to sustain industrial production.

Methods

New impact categories and characterization models are developed for the assessment of economic resource availability based on existing LCA methodology and terminology. A single score result can be calculated providing information about the economic resource scarcity potential (ESP) of different resources. Based on a life cycle perspective, the supply risk associated with resource use can be assessed, and bottlenecks within the supply chain can be identified. The analysis can be conducted in connection with existing LCA procedures and in line with current resource assessment practice and facilitates easy implementation on an organizational level.

Results and discussion

A portfolio of 17 metals is assessed based on different impact categories. Different impact factors are calculated, enabling identification of high-risk metals. Furthermore, a comparison of ESP and abiotic depletion potential (ADP) is conducted. Availability of resources differs significantly when economic aspects are taken into account in addition to geologic availability. Resources assumed uncritical based on ADP results, such as rare earths, turn out to be associated with high supply risks.

Conclusions

The model developed in this work allows for a more realistic assessment of resource availability beyond geologic finiteness. The new impact categories provide organizations with a practical measure to identify supply risks associated with resources. The assessment delivers a basis for developing appropriate mitigation measures and for increasing resilience towards supply disruptions. By including an economic dimension into resource availability assessment, a contribution towards life cycle sustainability assessment (LCSA) is achieved.     

Correlation analysis of life cycle impact assessment indicators measuring resource use

Introduction  

Even though the necessity of a sustainable use of natural resources is widely accepted, there is neither consensus on how “resource use” is clearly defined nor how it should be measured. Depending on the definition, it can comprise raw material consumption only or the consumption and pollution of natural resources. Consequently, lots of indicators can be applied, and the result of a life cycle assessment study aiming to quantify resource use seems to depend on the selection of impact categories. Therefore, this paper aims at analyzing life cycle impact assessment results obtained by means of several indicators to check if different indexes lead to similar results and if the number of indicators can be reduced.     

Bringing science and pragmatism together a tiered approach for modelling toxicological impacts in LCA

Goal, Scope and Background  The EU 5^th framework project OMNIITOX will develop models calculating characterisation factors for assessing the potential toxic impacts of chemicals within the framework of LCA. These models will become accessible through a web-based information system. The key objective of the OMNIITOX project is to increase the coverage of substances by such models. In order to reach this objective, simpler models which need less but available data, will have to be developed while maintaining scientific quality. Methods. Experience within the OMNIITOX project has taught that data availability and quality are crucial issues for calculating characterisation factors. Data availability determines whether calculating characterisation factors is possible at all, whereas data quality determines to what extent the resulting characterisation factors are reliable. Today, there is insufficient knowledge and/or resources to have high data availability as well as high data quality and high model quality at the same time. Results  The OMNIITOX project is developing two inter-related models in order to be able to provide LCA impact assessment characterisation factors for toxic releases for as broad a range of chemicals as possible: 1) A base model representing a state-of-the-art multimedia model and 2) a simple model derived from the base model using statistical tools. Discussion. A preliminary decision tree for using the OMNIITOX information system (IS) is presented. The decision tree aims to illustrate how the OMNIITOX IS can assist an LCA practitioner in finding or deriving characterisation factors for use in life cycle impact assessment of toxic releases. Conclusions and Outlook  Data availability and quality are crucial issues when calculating characterisation factors for the toxicity impact categories. The OMNIITOX project is developing a tiered model approach for this. It is foreseen that a first version of the base model will be ready in late summer of 2004, whereas a first version of the simple base model is expected a few months later.     

Assessing freshwater use impacts in LCA,part 2: case study of broccoli production in the UK and Spain

Background, aim and scope  

Milà i Canals et al. (Int J Life Cycle Ass 14(1):28-42, 2009) referred to as ‘Part 1’ in this paper) showed that impacts associated with use of freshwater must be treated more rigorously than is usual in life cycle assessment (LCA), going beyond the conventional consideration only of ‘blue’ water (i.e. irrigation and other abstractions), and suggested an operational method to include the impacts on freshwater ecosystems (freshwater ecosystem impact) and abiotic resource depletion (freshwater depletion). The inclusion of water-related impacts in LCA is of paramount importance, particularly for agricultural systems due to their large water consumption worldwide. A case study of UK consumption of broccoli grown in the UK and Spain is presented here to illustrate the method suggested in Part 1.     

Molecular characterisation and genetic mapping of candidate genes for qualitative disease resistance in perennial ryegrass (Lolium perenne L.)

Background  

Qualitative pathogen resistance in both dicotyledenous and monocotyledonous plants has been attributed to the action of resistance (R) genes, including those encoding nucleotide binding site – leucine rich repeat (NBS-LRR) proteins and receptor-like kinase enzymes. This study describes the large-scale isolation and characterisation of candidate R genes from perennial ryegrass. The analysis was based on the availability of an expressed sequence tag (EST) resource and a functionally-integrated bioinformatics database.     

Eutrophication of aquatic ecosystems a new method for calculating the potential contributions of nitrogen and phosphorus

Aim, Scope and Background  

Aquatic eutrophication is a widespread problem in inland and coastal waters around the world and it should therefore be one of the impact categories to be considered in LCA studies of products and services. In LCAs there are several impact assessment methods to determine characterisation factors for eutrophying nutrients, but few methods have been developed to model fate and spatial aspects. One such method was developed as part of an LCA application of the Finnish forest industry. The aim of this study was to present this characterisation method in which the potential contributions of nitrogen and phosphorus to eutrophication of aquatic ecosystems are calculated. The use of the method was demonstrated by producing site/sector-specific characterisation factors and by constructing a reference value of aquatic eutrophication for Finland. A discussion of sensitivity and uncertainty aspects related to input data is also presented.     

Accounting for overfishing in life cycle assessment: new impact categories for biotic resource use

Purpose

Overfishing is a relevant issue to include in all life cycle assessments (LCAs) involving wild caught fish, as overfishing of fish stocks clearly targets the LCA safeguard objects of natural resources and natural ecosystems. Yet no robust method for assessing overfishing has been available. We propose lost potential yield (LPY) as a midpoint impact category to quantify overfishing, comparing the outcome of current with target fisheries management. This category primarily reflects the impact on biotic resource availability, but also serves as a proxy for ecosystem impacts within each stock.

Methods

LPY represents average lost catches owing to ongoing overfishing, assessed by simplified biomass projections covering different fishing mortality scenarios. It is based on the maximum sustainable yield concept and complemented by two alternative methods, overfishing though fishing mortality (OF) and overfishedness of biomass (OB), that are less data-demanding.

Results and discussion

Characterization factors are provided for 31 European commercial fish stocks in 2010, representing 74 % of European and 7 % of global landings. However, large spatial and temporal variations were observed, requiring novel approaches for the LCA practitioner. The methodology is considered compliant with the International Reference Life Cycle Data System (ILCD) standard in most relevant aspects, although harmonization through normalization and endpoint characterization is only briefly discussed.

Conclusions

Seafood LCAs including any of the three approaches can be a powerful communicative tool for the food industry, seafood certification programmes, and for fisheries management.     

Uncertainties in the application of the species area relationship for characterisation factors of land occupation in life cycle assessment

Purpose  

Uncertainties in land use damage modeling are recognized, but hardly quantified in life cycle assessment (LCA). The objective of this study is to analyze the influence of various key assumptions and uncertainties within the development of characterisation factors (CFs) for land use in LCA. We assessed the influence on land use CFs of (1) parameter uncertainty and (2) the choice for a constant or land use-specific species accumulation factor z and including or excluding regional effects.     

Global characterisation factors to assess land use impacts on biotic production

Purpose

The inclusion of land-use activities in life cycle assessment (LCA) has been subject to much debate in the LCA community. Despite the recent methodological developments in this area, the impacts of land occupation and transformation on its long-term ability to produce biomass (referred to here as biotic production potential [BPP]) — an important endpoint for the Area of Protection (AoP) Natural Resources — have been largely excluded from LCAs partly due to the lack of life cycle impact assessment methods.

Materials and methods

Several possible methods/indicators for BPP associated with biomass, carbon balance, soil erosion, salinisation, energy, soil biota and soil organic matter (SOM) were evaluated. The latter indicator was considered the most appropriate for LCA, and characterisation factors for eight land use types at the climate region level were developed.

Results and discussion

Most of the indicators assessed address land-use impacts satisfactorily for land uses that include biotic production of some kind (agriculture or silviculture). However, some fail to address potentially important land use impacts from other life cycle stages, such as those arising from transport. It is shown that the change in soil organic carbon (SOC) can be used as an indicator for impacts on BPP, because SOC relates to a range of soil properties responsible for soil resilience and fertility.

Conclusions

The characterisation factors developed suggest that the proposed approach to characterize land use impacts on BBP, despite its limitations, is both possible and robust. The availability of land-use-specific and biogeographically differentiated data on SOC makes BPP impact assessments operational. The characterisation factors provided allow for the assessment of land-use impacts on BPP, regardless of where they occur thus enabling more complete LCAs of products and services. Existing databases on every country’s terrestrial carbon stocks and land use enable the operability of this method. Furthermore, BPP impacts will be better assessed by this approach as increasingly spatially specific data are available for all geographical regions of the world at a large scale. The characterisation factors developed are applied to the case studies (Part D of this special issue), which show the practical issues related to their implementation.     

Temporally explicit abiotic depletion potential (TADP) for mineral resource use based on future demand projections

Purpose

Assessing the potential impacts (characterization) of mineral resource use in life cycle impact assessment (LCIA) has long been debated. One of the most crucial challenges in the characterization models for mineral resource use is the consideration of the changing demand and availability of in-use stocks in the future, which is relevant to the global population and economy growth as well as the increasing low-carbon technologies. We propose an extended characterization model to assess the potential impacts for arbitrary time horizons, considering future demand changes and the availability of in-use stock: temporally explicit abiotic depletion potential (TADP).

Methods

The TADP was developed based on abiotic depletion potential (ADP), which is a widely used characterization model for mineral resource use. While the ADP assesses the potential impacts of mineral resource use based on a natural stock estimate and the current extraction rate, the TADP adopts an average extraction rate for arbitrary time horizons. The average extraction rate was estimated using material flow analysis considering future demand changes and recycling under the five shared socioeconomic pathways (SSPs). TADPs were calculated for six common metals: aluminum, copper, iron, lead, nickel, and zinc.

Results and discussion

As a result of calculating TADPs for the term by 2050 (TADP₂₀₅₀), compared to iron, all other metals showed larger values of characterization factors for all SSPs than the original ADPs. The TADP₂₀₅₀ of copper exhibited the largest difference with ADP among the six metals (approximately 1.9 times), which is mainly attributed to future demand growth. On the other hand, for the longer time perspective, the TADP₂₁₀₀ of lead and zinc exhibited larger differences with ADP than copper (approximately 2.8 times for zinc), which is mainly due to a relatively shorter lifetime for lead and a lower recycling rate for zinc. This suggests that the relative significance of the characterization factors of metals varies depending on the temporal perspective.

Conclusions

With the proposed characterization model, the potential impacts of mineral resource use can be assessed reflecting future situations for the selected time horizons. The results demonstrate that the consideration of future situations greatly influences the relative significance of the potential impacts of using different mineral resources in the results of LCIA studies. By expanding the coverage of mineral resources and future scenario analysis to other relevant factors, the TADP model can improve the robustness of the assessment and further support decision-making towards sustainable resource management.

     

Life-cycle assessment of domestic and transboundary recycling of post-consumer PET bottles

Background, aim, and scope  

In recent years, besides being recycled domestically, a part of Japanese post-consumer polyethylene terephthalate (PET) bottles have been exported to and recycled in mainland China. In this study, life-cycle assessment (LCA) was applied to compare domestic and transboundary recycling scenarios between Japan and China and disposal scenarios from the viewpoints of greenhouse gases (GHG) emission and fossil resource consumption.     

Regional normalisation figures for Australia 2005/2006—inventory and characterisation data from a production perspective

Background, aim, and scope  Under ISO 14040, normalisation is an optional step in life-cycle impact assessment designed to provide environmental context by indicating the relative contribution that the product system under investigation makes in the various impact categories, in comparison to a suitable reference scenario. The challenge for many studies, however, is to provide the appropriate context by adopting a normalisation reference scenario that is well matched to the product system’s parent environment. Australia has a highly urbanised population, mainly contained in just eight capital cities. In the context of normalising environmental impacts against the profile of an ‘average’ Australian, this poses a unique problem, compared to other industrialised regions of the world. This study aims to use publicly available data on environmentally relevant emissions and non-renewable resource consumption in 2005/2006 to develop regional normalisation data for Australia, at both inventory and characterisation levels. Methods  The regionalised inventory of emissions and resources production is constructed using a framework of 60 regional Statistical Divisions from the Australian Standard Geographical Classification system. Data from the National Pollutant Inventory, Australian Greenhouse Emissions Information System and the Australian Bureau of Agricultural and Resource Economics (energy and mineral statistics) are used as the basis for the inventories. These data could subsequently be used by any LCA practitioner to construct characterisation or normalisation data by impact category, according to any preferred life-cycle impact assessment methodology, for any of 60 regions in the country. In this study, the regionalised inventory data were assessed using the CML 2001 baseline and IMPACT 2002+ life-cycle impact assessment methods in SimaPro v.7.1.5. Results  Characterisation results from the two LCIA methods for Australia’s eight state and territory capital cities are presented, together with an overall national profile. These data are also shown on a per capita basis to highlight the relative environmental profiles of citizens in the different cities. Interestingly, many significant impacts occur outside of the capital cities but are linked to facilities providing the majority of their services and products to these urban centres (e.g. power stations, minerals processing). Comparison of the average Australian data with the Netherlands, Western Europe and the World shows the results to be broadly similar. Discussion  Analysis of the CML 2001 baseline characterisation results, on a per capita basis, shows substantial differences between the major cities of the country. In each impact category, these differences can be successfully traced to specific emissions in the raw data sources, the influence of prevailing climate conditions, or factors such as the mix of non-renewable energy resources in each state. Some weaknesses are also evident in the collection and estimation techniques of the raw data sources and in the application of European-based impact assessment models. Australia is a net exporter of many products, particularly natural resources. Therefore, a significant part of the characterisation data presented here for Australia represents products that will be consumed in other parts of the world. Similarly, at a regional level, there will be many inventory items produced in one area yet consumed in another. In this way, the impacts associated with consumption (particularly in densely populated but largely industry-free cities) are dissipated into other production centres. Conclusions  This study provides the first set of comprehensive inventory and characterisation data for Australia from a production perspective, disaggregated at a regional level. Despite Australia’s unique spatial demography, it is now possible to properly characterise the relative significance of environmental impacts occurring in any of 60 specific regions across the country. Recommendations and perspectives  Australia’s unique concentration of urban populations demonstrates the importance of regionally specific environmental assessments. Whilst the data presented in this study will be of most use to Australian LCA practitioners, it is also demonstrative of the broader global distribution of environmental impacts between urban and non-urban areas. The disconnection of environmental impacts between the place of production and the place of consumption is highlighted by this study and should be considered in any studies using these normalisation data for environmental profiling. Electronic supplementary material  The online version of this article (doi:) contains supplementary material, which is available to authorized users.     

Assessing freshwater use impacts in LCA: Part I—inventory modelling and characterisation factors for the main impact pathways

Background, aim and scope

Freshwater is a basic resource for humans; however, its link to human health is seldom related to lack of physical access to sufficient freshwater, but rather to poor distribution and access to safe water supplies. On the other hand, freshwater availability for aquatic ecosystems is often reduced due to competition with human uses, potentially leading to impacts on ecosystem quality. This paper summarises how this specific resource use can be dealt with in life cycle analysis (LCA).

Main features

The main quantifiable impact pathways linking freshwater use to the available supply are identified, leading to definition of the flows requiring quantification in the life cycle inventory (LCI).

Results

The LCI needs to distinguish between and quantify evaporative and non-evaporative uses of ‘blue’ and ‘green’ water, along with land use changes leading to changes in the availability of freshwater. Suitable indicators are suggested for the two main impact pathways [namely freshwater ecosystem impact (FEI) and freshwater depletion (FD)], and operational characterisation factors are provided for a range of countries and situations. For FEI, indicators relating current freshwater use to the available freshwater resources (with and without specific consideration of water ecosystem requirements) are suggested. For FD, the parameters required for evaluation of the commonly used abiotic depletion potentials are explored.

Discussion

An important value judgement when dealing with water use impacts is the omission or consideration of non-evaporative uses of water as impacting ecosystems. We suggest considering only evaporative uses as a default procedure, although more precautionary approaches (e.g. an ‘Egalitarian’ approach) may also include non-evaporative uses. Variation in seasonal river flows is not captured in the approach suggested for FEI, even though abstractions during droughts may have dramatic consequences for ecosystems; this has been considered beyond the scope of LCA.

Conclusions

The approach suggested here improves the representation of impacts associated with freshwater use in LCA. The information required by the approach is generally available to LCA practitioners

Recommendations and perspectives

The widespread use of the approach suggested here will require some development (and consensus) by LCI database developers. Linking the suggested midpoint indicators for FEI to a damage approach will require further analysis of the relationship between FEI indicators and ecosystem health.     

PIQET: the design and development of an online ‘streamlined’ LCA tool for sustainable packaging design decision support

Background, aim and scope  

‘Streamlined’ life cycle assessment (LCA) tools hold out the possibility of providing LCA information quickly and easily in order to support a variety of decision-making environments and situations. The utility of such tools is closely related to the accuracy needs and possibilities, and the particular decisions to be supported. In order to facilitate the provision and application of LCA information in decision making during packaging design, development and utilisation, there is a prima facia case for a ‘streamlined’ LCA tool, provided it meets a set of requirements, including functionality, accuracy, validity, reliability and usability.     

Conventional and exergetic life cycle assessment of organic rankine cycle implementation to municipal waste management: the case study of Mae Hong Son (Thailand)

Purpose

The critical issue of waste management in Thailand has been rapidly increasing in almost all of the cities due to the economic growth and rising population that could double the amount of solid waste in landfill area. The alternative ways of waste treatment that have more efficiency and effectiveness in terms of energy, ecology, and resources become the key issue for each municipality to replace the old fashioned technology and be able to enhance the ability of solid waste problem management. Waste to energy is one of the favorable approaches to diminish the amount of waste to landfill and utilize waste for electricity. The aim of this study is to identify and quantify the life cycle impacts of the municipal solid waste (MSW) of Mae Hong Son municipality (MHSM), and the case study is the selected waste treatment technology of the Refuse-Derived Fuel (RDF) hybrid with 20 kW of Organic Rankine Cycle (ORC).

Methods

The functional unit is defined as 1 t of MSW. The energy, environment, and resource impacts were evaluated by using Life Cycle Assessment (LCA); ReCipe and Net Energy Consumption were referred to calculate the environmental impacts and the benefits of energy recovery of WtE technology. Exergetic LCA was used to analyze the resource consumption, especially land use change.

Results and discussion

The results indicated that the environmental impacts were comparatively high at the operation stage of RDF combustion. On the other hand, the production stage of RDF illustrated the highest energy consumption. The ORC power generation mainly consumed resources from material and energy used. The ORC system demonstrated better results in terms of energy and resource consumption when applied to waste management, especially the land required for landfill. Substitution of electricity production from ORC system was the contributor to the reduction of both energy and resource consumption. Installation of spray dry and fabric filter unit to RDF burner can reduce heavy metals and some pollutants leading to the reduction of most of the impacts such as climate change, human toxicity, and fossil depletion which are much lower than the conventional landfill.

Conclusions

LCA results revealed that the environmental impacts and energy consumption can be reduced by applying the RDF and ORC systems. The exergetic LCA is one of the appropriate tools used to evaluate the resource consumption of MSW. It is obviously proven that landfill contributed to higher impacts than WtE for waste management.

     

Towards harmonizing natural resources as an area of protection in life cycle impact assessment

Purpose

In this paper, we summarize the discussion and present the findings of an expert group effort under the umbrella of the United Nations Environment Programme (UNEP)/Society of Environmental Toxicology and Chemistry (SETAC) Life Cycle Initiative proposing natural resources as an Area of Protection (AoP) in Life Cycle Impact Assessment (LCIA).

Methods

As a first step, natural resources have been defined for the LCA context with reference to the overall UNEP/SETAC Life Cycle Impact Assessment (LCIA) framework. Second, existing LCIA methods have been reviewed and discussed. The reviewed methods have been evaluated according to the considered type of natural resources and their underlying principles followed (use-to-availability ratios, backup technology approaches, or thermodynamic accounting methods).

Results and discussion

There is currently no single LCIA method available that addresses impacts for all natural resource categories, nor do existing methods and models addressing different natural resource categories do so in a consistent way across categories. Exceptions are exergy and solar energy-related methods, which cover the widest range of resource categories. However, these methods do not link exergy consumption to changes in availability or provisioning capacity of a specific natural resource (e.g., mineral, water, land etc.). So far, there is no agreement in the scientific community on the most relevant type of future resource indicators (depletion, increased energy use or cost due to resource extraction, etc.). To address this challenge, a framework based on the concept of stock/fund/flow resources is proposed to identify, across natural resource categories, whether depletion/dissipation (of stocks and funds) or competition (for flows) is the main relevant aspect.

Conclusions

An LCIA method—or a set of methods—that consistently address all natural resource categories is needed in order to avoid burden shifting from the impact associated with one resource to the impact associated with another resource. This paper is an important basis for a step forward in the direction of consistently integrating the various natural resources as an Area of Protection into LCA.

     

Post-consumer waste wood in attributive product LCA

Background  

In product life cycle assessment (LCA), the attribution of environmental interventions to a product under study is an ambiguous task. This is due to a) the simplistic modeling characteristics in the life cycle inventory step (LCI) of LCA in view of the complexity of our techno-economic system, and b) to the nontangible theoretical nature of the product system as a representation of the processes ‘causally’ linked to a product. Ambiguous methodological decisions during the setup of an LCI include the modeling of end-of-life scenarios or the choice of an allocation factor for the allocation of joint co-production processes. An important criterion for methodological decisions — besides the conformity with the relevant series of standards ISO 14 040 — is if the improvement options, which can be deduced from the LCI, are perceived by the decision-maker as to redirect the material flows at stake into more sustainable paths.