A spatially explicit life cycle assessment midpoint indicator for soil quality in the European Union using soil organic carbon

Purpose

Improving land use assessment in life cycle assessment (LCA) is a priority. Recently, soil organic carbon (SOC) depletion has been proposed as a transformation and occupation midpoint indicator to estimate impacts on biotic production potential (BPP). SOC depletion is recommended by the European Union in the International Reference Life Cycle Data System (ILCD) Handbook as a land use indicator. There is a consensus method to calculate SOC depletion in LCA, and ILCD proposes a set of characterization factors (CFs), but these lack geographical discrimination.

Methods

Our method of calculation for midpoint CFs follows Brandão and Milà i Canals (Int J Life Cycle Assess 18:1243–1252, 2013). We operationalize the method using SOC stocks from the LUCASOIL database of field measurements in Europe. We use potential natural vegetation (PNV) as the reference situation. CFs were calculated on a cell basis for 23 countries in Europe and grouped in three spatial scales (an administrative classification, NUTS II, and two biophysical classifications, ecoregion and climate region) according to soil type and land cover following a consensus map of cover classes. To evaluate the method’s results, CFs were applied in a case study.

Results and discussion

SOC stocks of European soils were obtained according to land use and soil type classes (excluding non-European Union countries) for the three spatial scales. A database of European transformation and occupation CFs is also presented and analyzed. The aggregation of CFs at biophysical scales (ecoregion and climate region) is similar, but NUTS II aggregation of CFs is problematic. The application of the CFs in the case study revealed significant differences compared to the outcome of using CFs collected from other land use models.

Conclusions

This paper is the first operationalization using field measurements of an updated version of the ILCD-recommended model for land use impacts in LCA. We obtained CFs for SOC depletion in Europe that can be nested within CFs suggested by ILCD since our results possess better spatial resolution but are only for European Union countries. The case study application highlighted the need for inventories to improve the spatial resolution of the life cycle processes to match the detail of LCIA models.

     

LCA of petroleum-based lubricants: state of art and inclusion of additives

Purpose

While the application of Life Cycle Assessment (LCA) to lubricants can be considered fully operational for general purposes outside the lubricants industry, where Life Cycle Inventories (LCIs) of mineral and synthetic base oils can be used interchangeably and where additives can be excluded, this is not the case for research and development purposes within the industry. Previous LCAs of base oils are not sufficiently detailed and comprehensive for R&D purposes, and there are no LCAs of lube additives and fully formulated lubricants. The aim of this paper is to integrate and expand previous LCAs of base oils and to investigate on the contribution of lube additives to the environmental impacts of a fully formulated lubricant.

Materials and methods

This study considers three base oils (mineral, poly-alpha-olefins (PAO) and hydrocracked) and a set of lubricating additives typically used in fully formulated engine oil. The LCA model is based on both industry and literature data.

Results and discussion

Trends in the lubricants industry towards more sophisticated base oils correspond to remarkably higher environmental impacts per kilogram of product but lead to reduced impacts per kilometre. The contribution of additives to the life cycle impacts of commercial lube oil was found to be remarkably high for some impact categories (nearly 35?% for global warming).

Conclusions

As base oil is concerned, this study made the point on data availability and provided a contribution in order to integrate and expand previous LCAs of mineral base oil and PAO. On the side of additives, the main conclusion is that in modern lubricants, the contribution of additives in terms of environmental impact can be remarkably high and, therefore, they should not be excluded.     

Inclusion of soil erosion impacts in life cycle assessment on a global scale: application to energy crops in Spain

Purpose

Despite the fundamental role of ecosystem goods and services in sustaining human activities, there is no harmonized and internationally agreed method for including them in life cycle assessment (LCA). The main goal of this study was to develop a globally applicable and spatially resolved method for assessing land use impacts on the erosion regulation ecosystem service.

Methods

Soil erosion depends much on location. Thus, unlike conventional LCA, the endpoint method was regionalized at the grid cell level (5 arcmin, approximately 10?×?10 km²) to reflect the spatial conditions of the site. Spatially explicit characterization factors were not further aggregated at broader spatial scales.

Results and discussion

Life cycle inventory data of topsoil and topsoil organic carbon (SOC) losses were interpreted at the endpoint level in terms of the ultimate damage to soil resources and ecosystem quality. Human health damages were excluded from the assessment. The method was tested on a case study of five 3-year agricultural rotations, two of them with energy crops, grown in several locations in Spain. A large variation in soil and SOC losses was recorded in the inventory step, depending on climatic and edaphic conditions. The importance of using a spatially explicit model and characterization factors is shown in the case study.

Conclusions

The regionalized assessment takes into account the differences in soil erosion-related environmental impacts caused by the great variability of soils. Taking this regionalized framework as the starting point, further research should focus on testing the applicability of the method through the complete life cycle of a product and on determining an appropriate spatial scale at which to aggregate characterization factors in order to deal with data gaps on the location of processes, especially in the background system. Additional research should also focus on improving the reliability of the method by quantifying and, insofar as it is possible, reducing uncertainty.     

System delimitation in agricultural consequential LCA

Background, aim, and scope

When dealing with system delimitation in environmental life cycle assessment (LCA), two methodologies are typically referred to: consequential LCA and attributional LCA. The consequential approach uses marginal data and avoids co-product allocation by system expansion. The attributional approach uses average or supplier-specific data and treats co-product allocation by applying allocation factors. Agricultural LCAs typically regard local production as affected and they only include the interventions related to the harvested area. However, as changes in demand and production may affect foreign production, yields and the displacement of other crops in regions where the agricultural area is constrained, there is a need for incorporating the actual affected processes in agricultural consequential LCA. This paper presents a framework for defining system boundaries in consequential agricultural LCA. The framework is applied to an illustrative case study; LCA of increased demand for wheat in Denmark. The aim of the LCA screening is to facilitate the application of the proposed methodology. A secondary aim of the LCA screening is to illustrate that there are different ways to meet increased demand for agricultural products and that the environmental impact from these different ways vary significantly.

Materials and methods

The proposed framework mainly builds on the work of Ekvall T, Weidema BP (Int J Life Cycle Assess 9(3):pp. 161–171, 2004), agricultural statistics (FAOSTAT, FAOSTAT Agriculture Data, Food and Agriculture Organisation of the United Nations (2006), http://apps.fao.org/ (accessed June)), and agricultural outlook (FAPRI, US and world agricultural outlook, Food and Agriculture Research Institute, Iowa, 2006a). The framework and accompanying guidelines concern the suppliers affected, the achievement of increased production (area or yield), and the substitutions between crops. The framework, which is presented as a decision tree, proposes four possible systems that may be affected as a result of the increased demand of a certain crop in a certain area.

Results

The core of the proposed methodology is a decision tree, which guides the identification of affected processes in consequential agricultural LCA. The application of the methodology is illustrated with a case study presenting an LCA screening of wheat in Denmark. Different scenarios of how increased demand for wheat can be met show significant differences in emission levels as well as land use.

Discussion

The great differences in potential environmental impacts of the analysed results underpin the importance of system delimitation. The consequential approach is appointed as providing a more complete and accurate but also less precise result, while the attributional approach provides a more precise result but with inherent blind spots, i.e. a less accurate result.

Conclusions

The main features of the proposed framework and case study are: (1) an identification of significant sensitivity on results of system delimitation, and (2) a formalised way of identifying blind spots in attributional agricultural LCAs.

Recommendations and perspectives

It is recommended to include considerations on the basis of the framework presented in agricultural LCAs if relevant. This may be done either by full quantification or as qualitative identification of the most likely ways the agricultural product system will respond on changed demand. Hereby, it will be possible to make reservations to the conclusions drawn on the basis of an attributional LCA.     

Is land use impact assessment in LCA applicable for forest biomass value chains? Findings from comparison of use of Scandinavian wood,agro-biomass and peat for energy

Purpose

A framework for the inclusion of land use impact assessment and a set of land use impact indicators has been recently proposed for life cycle assessment (LCA) and no case studies are available for forest biomass. The proposed methodology is tested for Scandinavian managed forestry; a comparative case study is made for energy from wood, agro-biomass and peat; and sensitivity to forest management options is analysed.

Methods

The functional unit of this comparative case study is 1 GJ of energy in solid fuels. The land use impact assessment framework of the United Nations Environment Programme and the Society of Environmental Toxicology and Chemistry (UNEP-SETAC) is followed and its application for wood biomass is critically analysed. Applied midpoint indicators include ecological footprint and human appropriation of net primary production, global warming potential indicator for biomass (GWP_bio-100) and impact indicators proposed by UNEP-SETAC on ecosystem services and biodiversity. Options for forest biomass land inventory modelling are discussed. The system boundary covers only the biomass acquisition phase. Management scenarios are formulated for forest and barley biomass, and a sensitivity analysis focuses on impacts of land transformations for agro-biomass.

Results and discussion

Meaningful differences were found in between solid biofuels from distinct land use classes. The impact indicator results were sensitive to land occupation and transformation and differed significantly from inventory results. Current impact assessment method is not sensitive to land management scenarios because the published characterisation factors are still too coarse and indicate differences only between land use types. All indicators on ecosystem services and biodiversity were sensitive to the assumptions related with land transformation. The land occupation (m²a) approach in inventory was found challenging for Scandinavian wood, due to long rotation periods and variable intensities of harvests. Some suggestions of UNEP-SETAC were challenged for the sake of practicality and relevance for decision support.

Conclusions

Land use impact assessment framework for LCA and life cycle impact assessment (LCIA) indicators could be applied in a comparison of solid bioenergy sources. Although forest bioenergy has higher land occupation than agro-bioenergy, LCIA indicator results are of similar magnitude or even lower for forest bioenergy. Previous literature indicates that environmental impacts of land use are significant, but it remains questionable if these are captured with satisfactory reliability with the applied LCA methodology, especially for forest biomass. Short and long time perspectives of land use impacts should be studied in LCA with characterisation factors for all relevant timeframes, not only 500 years, with a forward-looking perspective. Characterisation factors need to be modelled further for different (forest) land management intensities and for peat excavation.     

Including CO2 implications of land occupation in LCAs—method and example for livestock products

Purpose

Until recently, life cycle assessments (LCAs) have only addressed the direct greenhouse gas emissions along a process chain, but ignored the CO₂ emissions of land-use. However, for agricultural products, these emissions can be substantial. Here, we present a new methodology for including the implications of land occupation for CO₂ emissions to realistically reflect the consequences of consumers?? decisions.

Method

In principle, one can distinguish five different approaches of addressing the CO₂ consequences of land occupation: (1) assuming constant land cover, (2) land-use change related to additional production of the product under consideration, (3) historic land-use change, assuming historical relations between existing area and area expansion (4) land-use change related to less production of the product under consideration (??missed potential carbon sink?? of land occupation), and (5) an approach of integrating land conversion emissions and delayed uptake due to land occupation. Approach (4) is presented in this paper, using LCA data on land occupation, and carbon dynamics from the IMAGE model. Typically, if less production occurs, agricultural land will be abandoned, leading to a carbon sink when vegetation is regrowing. This carbon sink, which does not occur if the product would still be consumed, is thus attributed to the product as ??missed potential carbon sink??, to reflect the CO₂ implications of land occupations.

Results

We analyze the missed potential carbon sink by relating land occupation data from LCA studies to the potential carbon sink as calculated by an Integrated Global Assessment Model and its process-based, spatially explicit carbon cycle model. Thereby, we account for regional differences, heterogeneity in land-use, and different time horizons. Example calculations for several livestock products show that the CO₂ consequences of land occupation can be in the same order of magnitude as the other process related greenhouse gas emissions of the LCA, and depend largely on the production system. The highest CO₂ implications of land occupation are calculated for beef and lamb, with beef production in Brazil having a missed potential carbon sink more than twice as high as the other GHG emissions.

Conclusions

Given the significant contribution of land occupation to the total GHG balance of agricultural products, they need to be included in life cycle assessments in a realistic way. The new methodology presented here reflects the consequences of producing or not producing a certain commodity, and thereby it is suited to inform consumers fully about the consequences of their choices.     

Utilization of recovered wood in cascades versus utilization of primary wood—a comparison with life cycle assessment using system expansion

Purpose

A cascading utilization of resources is encouraged especially by legislative bodies. However, only few consecutive assessments of the environmental impacts of cascading are available. This study provides answers to the following questions for using recovered wood as a secondary resource: (1) Does cascading decrease impacts on the environment compared to the use of primary wood resources? (2) What aspects of the cascading system are decisive for the life cycle assessment (LCA) results?

Methods

We conducted full LCAs for cascading utilization options of waste wood and compared the results to functionally equivalent products from primary wood, thereby focusing on the direct effects cascading has on the environmental impacts of the systems. In order to compare waste wood cascading to the use of primary wood with LCA, a functional equivalence of the systems has to be achieved. We applied a system expansion approach, considering different options for providing the additionally needed energy for the cascading system.

Results and discussion

We found that the cascading systems create fewer environmental impacts than the primary wood systems, if system expansion is based on wood energy. The most noticeable advantages were detected for the impact categories of land transformation and occupation and the demand of primary energy from renewable sources. The results of the sensitivity analyses indicate that the advantage of the cascading system is robust against the majority of considered factors. Efficiency and the method of incineration at the end of life do influence the results.

Conclusions

To maximize the benefits and minimize the associated environmental impacts, cascading proves to be a preferable option of utilizing untreated waste wood.     

Parameterized tool for site specific LCAs of wind energy converters

Purpose

The purpose of this project was to provide a parameterized LCA tool that allows performing site specific life cycle assessments for different wind energy converter types by varying a limited number of relevant parameters. Hereby, it addresses the limited transferability of WEC LCA results to other sites as well as the increasing demand for such data.

Methods

Basis of the work was an extensive primary data collection at the respective production facilities and other relevant stakeholders like site assessment, service etc. Most of the required data was available at first hand and was completed with data from literature and LCA databases. Based on this data, a complex parameterized material flow model has been built and different product variants have been pre-defined within the model, including relevant production processes and upstream. The pre-definition of these product variants allows reducing the minimum number of parameters that need to be configured for site specific LCAs from a total of over 330 to just nine parameters.

Results and conclusions

In the future, choosing the right type of technology for specific sites will become more important; especially in the face of increasing land use conflicts and increasing competition between renewable energy technologies. Site and technology specific LCAs prove to be a valuable tool for this assessment. Tools like the presented significantly reduce the effort required for performing these LCAs. Additionally, they can be used for various other purposes like environmental assessments of different repowering scenarios and eco design.     

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.     

Life cycle assessment evaluation of green product labeling systems for residential construction

Purpose

Life cycle assessment (LCA) is a tool that can be utilized to holistically evaluate novel trends in the construction industry and the associated environmental impacts. Green labels are awarded by several organizations based on single or multiple attributes. The use of multi-criteria labels is a good start to the labeling process as opposed to single criteria labels that ignore a majority of impacts from products. Life cycle thinking, in theory, has the potential to improve the environmental impacts of labeling systems. However, LCA databases currently are lacking in detailed information about products or sometimes provide conflicting information.

Method

This study compares generic and green-labeled carpets, paints, and linoleum flooring using the Building for Environmental and Economic Sustainability (BEES) LCA database. The results from these comparisons are not intuitive and are contradictory in several impact categories with respect to the greenness of the product. Other data sources such as environmental product declarations and ecoinvent are also compared with the BEES data to compare the results and display the disparity in the databases.

Results

This study shows that partial LCAs focused on the production and transportation phase help in identifying improvements in the product itself and improving the manufacturing process but the results are uncertain and dependent upon the source or database. Inconsistencies in the data and missing categories add to the ambiguity in LCA results.

Conclusions

While life cycle thinking in concept can improve the green labeling systems available, LCA data is lacking. Therefore, LCA data and tools need to improve to support and enable market trends.     

Improving odour assessment in LCA—the odour footprint

Purpose

Odour is an important aspect of systems for human and agricultural waste management and many technologies are developed with the sole purpose of reducing odour. Compared with greenhouse gas assessment and the assessment of toxicity, odour assessment has received little attention in the life cycle assessment (LCA) community. This article aims to redress this.

Methods

Firstly, a framework for the assessment of odour impacts in LCA was developed considering the classical LCA framework of emissions, midpoint and endpoint indicators. This suggested that an odour footprint midpoint indicator was worth striving for. An approach to calculating an areal indicator we call “odour footprint”, which considers the odour detection threshold, the diffusion rate and the kinetics of degradation of odourants, was implemented in MATLAB. We demonstrated the use of the characterisation factors we calculated in a case study based on odour removal technology applied to a pig barn.

Results and discussion

We produced a list of 33 linear characterisation factors based on hydrogen sulphide equivalents, analogous to the linear carbon dioxide equivalency factors in use in carbon footprinting, or the dichlorobenzene equivalency factors developed for assessment of toxic impacts in LCA. Like the latter, this odour footprint method does not take local populations and exposure pathway analysis into account—its intent is not to assess regulatory compliance or detailed design. The case study showed that despite the need for materials and energy, large factor reductions in odour footprint and eutrophication potential were achieved at the cost of a smaller factor increase in greenhouse emissions.

Conclusions

The odour footprint method is proposed as an improvement on the established midpoint method for odour assessment in LCA. Unlike it, the method presented here considers the persistence of odourants. Over time, we hope to increase the number of characterised odourants, enabling analysts to perform simple site-generic LCA on systems with odourant emissions.     

A review of life cycle assessments on wind energy systems

Purpose

Several life cycle assessments (LCAs) of wind energy published in recent years are reviewed to identify methodological differences and underlying assumptions.

Methods

A full comparative analysis of 12 studies were undertaken (ten peer-reviewed papers, one conference paper, and one industry report) regarding six fundamental factors (methods used, energy use accounting, quantification of energy production, energy performance and primary energy, natural resources, and recycling). Each factor is discussed in detail to highlight strengths and shortcomings of various approaches.

Results

Several potential issues are found concerning the way LCA methods are used for assessing energy performance and environmental impact of wind energy, as well as dealing with natural resource use and depletion. The potential to evaluate natural resource use and depletion impacts from wind energy appears to be poorly exploited or elaborated on in the reviewed studies. Estimations of energy performance and environmental impacts are critically analyzed and found to differ significantly.

Conclusions and recommendations

A continued discussion and development of LCA methodology for wind energy and other energy resources are encouraged. Efforts should be made to standardize methods and calculations. Inconsistent use of terminology and concepts among the analyzed studies are found and should be remedied. Different methods are generally used and the results are presented in diverse ways, making it difficult to compare studies with each other, but also with other renewable energy sources.     

Life cycle assessment in green chemistry: overview of key parameters and methodological concerns

Purpose

Several articles within the area of green chemistry often promote new techniques or products as ‘green’ or ‘more environmentally benign’ than their conventional counterpart although these articles often do not quantitatively assess the environmental performance. In order to do this, life cycle assessment (LCA) is a valuable methodology. However, on the planning stage, a full-scale LCA is considered to be too time consuming and complicated. Two reasons for this have been recognised, the method is too comprehensive and it is hard to find inventory data. In this review, key parameters are presented with the purpose to reduce the time-consuming steps in LCA.

Methods

In this review, several LCAs of so-called ‘green chemicals’ are analysed and key parameters and methodological concerns are identified. Further, some conclusions on the environmental performance of chemicals were drawn.

Results and discussion

For fossil-based platform chemicals several LCAs exists but for chemicals produced with industrial biotechnology or from renewable resources the number of LCAs is limited, with the exception of biofuels, for which a large number of studies are made. In the review, a significant difference in the environmental performance of bulk and fine chemicals was identified. The environmental performance of bulk chemicals are closely connected to the production of the raw material and thereby different land use aspects. Here, a lot can be learnt from biofuel LCAs. In many of the reviewed articles focusing on bulk chemicals a comparison regarding fossil and renewable raw material was done. In most of the comparisons the renewable alternative turned out to be more environmentally preferable, especially for the impact on GWP and energy use. However, some environmental concerns were identified as important to include to assess overall environmental concern, for example eutrophication and the use of land.

Conclusions

To assess the environmental performance of green chemicals, quantitative methods are needed. For this purpose, both simple metrics and more comprehensive methods have been developed, one recognised method being LCA. However, this method is often too time consuming to be valuable in the process planning stage. This is partly due to a lack of available inventory data, but also because the method itself is too comprehensive. Here, key parameters for the environmental performance and methodological concerns were described to facilitate a faster and simpler use of LCA of green chemicals in the future.     

Land use impact assessment in the construction sector: an analysis of LCIA models and case study application

Purpose

Land use is a potentially important impact category in life cycle assessment (LCA) studies of buildings. Three research questions are addressed in this paper: Is land use a decisive factor in the environmental impact of buildings?; Is it important to include the primary land use of buildings in the assessment?; and How does the environmental performance of solid structure and timber frame dwellings differ when assessed by distinct available models for quantifying land use impacts?

Methods

This paper compares several operational land use impact assessment models, which are subsequently implemented in an LCA case study comparing a building constructed using timber frame versus a solid structure. Different models were used for addressing the different research questions.

Results and discussion

The results reveal that contrasting decisions may be supported by LCA study results, depending on whether or not and how land use is included in the assessment. The analysis also highlights the need to include the building land footprint in the assessment and to better distinguish building locations in current land use impact assessment models.

Conclusions

Selecting land use assessment models that are most appropriate to the goals of the study is recommended as different models assess different environmental issues related to land use. In general, the combination of two land use assessment methods for buildings is recommended, i.e. soil organic matter (SOM) of Milà i Canals and Eco-indicator 99.     

Development of a soil compaction indicator in life cycle assessment

Purpose

Integrating soil quality impacts in life cycle assessment (LCA) requires a global approach to assess impacts on soil quality that can be adapted to individual soil and climate contexts. We have developed a framework for quantifying indicators of impact on soil quality, valid for all soil and climate conditions, and considering both on-site and off-site agricultural soils. Herein, we present one of the framework’s impact indicators, which has not yet been quantified in detail in LCA studies: soil compaction.

Material and methods

The method includes guidelines and tools for estimating midpoint compaction impacts in topsoil and subsoil as a loss of soil pore volume (in cubic metre per functional unit). The life cycle inventory (LCI) and life cycle impact assessment are based on simulation modelling, using models simple enough for use by non-experts, general enough to be parameterised with available data at a global scale and already validated. Data must be as site specific and accurate as possible, but if measured data are missing, the method has a standardised framework of rules and recommendations for estimating or finding them. The main model used, COMPSOIL, predicts compaction due to agricultural traffic. Results are illustrated using a case study involving several crops in different soil and climate conditions: a representative pig feed produced in Brittany, France.

Results and discussion

Predicted compaction impacts result from the combination of site-specific soil, climate and management characteristics. The data necessary to the LCI are readily available from free soil and climate databases and research online. Results are consistent with compaction observed in the field. Within a soil type, predictions are most sensitive to initial bulk density and soil water content.

Conclusions

The method lays the foundation for possible improvement by refining estimates of initial soil conditions or adding models that are simple and robust enough to increase the method’s capacity and accuracy. The soil compaction indicator can be used in LCAs of bio-based materials and of waste management stages that consider composting. The framework includes other operational indicators (i.e. water erosion, soil organic matter change) to assess impact on soil quality. They complement other impact categories, providing increased ability to identify “impact swapping”.     

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.     

Life cycle assessment in the minerals and metals sector: a critical review of selected issues and challenges

Background, aim and scope

The mining sector provides materials that are essential elements in a wide range of goods and services, which create value by meeting human needs. Mining and processing activities are an integral part of most complex material cycles so that the application of life cycle assessment (LCA) to minerals and metals has therefore gained prominence. In the past decade, increased use of LCA in the mineral and metal sector has advanced the scientific knowledge through the development of scientifically valid life cycle inventory databases. Though scientifically valid, LCA still needs to depend on several technical assumptions. In particular, measuring the environmental burden issues related to abiotic resource depletion, land use impacts and open-loop recycling within the LCA are widely debated issues. Also, incorporating spatial and temporal sensitivities in LCA, to make it a consistent scientific tool, is yet to be resolved. This article discusses existing LCA methods and proposed models on different issues in relation to minerals and metals sector.

Main features

A critical review was conducted of existing LCA methods in the minerals and metals sector in relation to allocation issues related to indicators of land use impacts, abiotic resource depletion, allocation in open-loop recycling and the system expansions and accounting of spatial and temporal dimension in LCA practice.

Results

Evolving a holistic view about these contentious issues will be presented with view for future LCA research in the minerals and metals industry. This extensive literature search uncovers many of the issues that require immediate attention from the LCA scientific community.

Discussion

The methodological drawbacks, mainly problems with inconsistencies in LCA results for the same situation under different assumptions and issues related to data quality, are considered to be the shortcomings of current LCA. In the minerals and metals sector, it is important to increase the objectivity of LCA by way of fixing those uncertainties, for example, in the LCA of the minerals and metals sector, whether the land use has to be considered in detail or at a coarse level. In regard to abiotic resource characterisation, the weighting and time scales to be considered become a very critical issue of judgement. And, in the case of open-loop recycling, which model will best satisfy all the stake holders? How the temporal and spatial dimensions should be incorporated into LCA is one of the biggest challenges ahead of all those who are concerned. Addressing these issues shall enable LCA to be used as a policy tool in environmental decision-making. There has been enormous debate with respect to on land use impacts, abiotic resource depletion, open-loop recycling and spatial and temporal dimensions, and these debates remain unresolved. Discussions aimed at bringing consensus amongst all the stake holders involved in LCA (i.e. industry, academia, consulting organisations and government) will be presented and discussed. In addition, a commentary of different points of view on these issues will be presented.

Conclusions

This review shall bring into perspective some of those contentious issues that are widely debated by many researchers. The possible future directions proposed by researchers across the globe shall be presented. Finally, authors conclude with their views on the prospects of LCA for future research endeavours.

Recommendations and outlook

Specific LCA issues of minerals and metals need to be investigated further to gain more understanding. To facilitate the future use of LCA as a policy tool in the minerals and metals sector, it is important to increase the objectivity with more scientific validity. Therefore, it is essential that the issues discussed in this paper are addressed to a great detail.     

UNEP-SETAC guideline on global land use impact assessment on biodiversity and ecosystem services in LCA

Purpose

As a consequence of the multi-functionality of land, the impact assessment of land use in Life Cycle Impact Assessment requires the modelling of several impact pathways covering biodiversity and ecosystem services. To provide consistency amongst these separate impact pathways, general principles for their modelling are provided in this paper. These are refinements to the principles that have already been proposed in publications by the UNEP-SETAC Life Cycle Initiative. In particular, this paper addresses the calculation of land use interventions and land use impacts, the issue of impact reversibility, the spatial and temporal distribution of such impacts and the assessment of absolute or relative ecosystem quality changes. Based on this, we propose a guideline to build methods for land use impact assessment in Life Cycle Assessment (LCA).

Results

Recommendations are given for the development of new characterization models and for which a series of key elements should explicitly be stated, such as the modelled land use impact pathways, the land use/cover typology covered, the level of biogeographical differentiation used for the characterization factors, the reference land use situation used and if relative or absolute quality changes are used to calculate land use impacts. Moreover, for an application of the characterisation factors (CFs) in an LCA study, data collection should be transparent with respect to the data input required from the land use inventory and the regeneration times. Indications on how generic CFs can be used for the background system as well as how spatial-based CFs can be calculated for the foreground system in a specific LCA study and how land use change is to be allocated should be detailed. Finally, it becomes necessary to justify the modelling period for which land use impacts of land transformation and occupation are calculated and how uncertainty is accounted for.

Discussion

The presented guideline is based on a number of assumptions: Discrete land use types are sufficient for an assessment of land use impacts; ecosystem quality remains constant over time of occupation; time and area of occupation are substitutable; transformation time is negligible; regeneration is linear and independent from land use history and landscape configuration; biodiversity and multiple ecosystem services are independent; the ecological impact is linearly increasing with the intervention; and there is no interaction between land use and other drivers such as climate change. These assumptions might influence the results of land use Life Cycle Impact Assessment and need to be critically reflected.

Conclusions and recommendations

In this and the other papers of the special issue, we presented the principles and recommendations for the calculation of land use impacts on biodiversity and ecosystem services on a global scale. In the framework of LCA, they are mainly used for the assessment of land use impacts in the background system. The main areas for further development are the link to regional ecological models running in the foreground system, relative weighting of the ecosystem services midpoints and indirect land use.     

Using a crop model to account for the effects of local factors on the LCA of sugar beet ethanol in Picardy region, France

Purpose

The results of published Life Cycle Assessments (LCAs) of biofuels are characterized by a large variability, arising from the diversity of both biofuel chains and the methodologies used to estimate inventory data. Here, we suggest that the best option to maximize the accuracy of biofuel LCA is to produce local results taking into account the local soil, climatic and agricultural management factors.

Methods

We focused on a case study involving the production of first-generation ethanol from sugar beet in the Picardy region in Northern France. To account for local factors, we first defined three climatic patterns according to rainfall from a 20-year series of weather data. We subsequently defined two crop rotations with sugar beet as a break crop, corresponding to current practice and an optimized management scenario, respectively. The six combinations of climate types and rotations were run with the process-based model CERES-EGC to estimate crop yields and environmental emissions. We completed the data inventory and compiled the impact assessments using Simapro v.7.1 and Ecoinvent database v2.0.

Results

Overall, sugar beet ethanol had lower impacts than gasoline for the abiotic depletion, global warming, ozone layer depletion and photochemical oxidation categories. In particular, it emitted between 28 % and 42 % less greenhouse gases than gasoline. Conversely, sugar beet ethanol had higher impacts than gasoline for acidification and eutrophication due to losses of reactive nitrogen in the arable field. Thus, LCA results were highly sensitive to changes in local conditions and management factors. As a result, an average impact figures for a given biofuel chain at regional or national scales may only be indicative within a large uncertainty band.

Conclusions

Although the crop model made it possible to take local factors into account in the life-cycle inventory, best management practices that achieved high yields while reducing environmental impacts could not be identified. Further modelling developments are necessary to better account for the effects of management practices, in particular regarding the benefits of fertiliser incorporation into the topsoil in terms of nitrogen losses abatement. Supplementary data and modelling developments also are needed to better estimate the emissions of pesticides and heavy metals in the field.