On the boundary between economy and environment in life cycle assessment

Purpose

We investigate how the boundary between product systems and their environment has been delineated in life cycle assessment and question the usefulness and ontological relevance of a strict division between the two.

Methods

We consider flows, activities and impacts as general terms applicable to both product systems and their environment and propose that the ontologically relevant boundary is between the flows that are modelled as inputs to other activities (economic or environmental)—and the flows that—in a specific study—are regarded as final impacts, in the sense that no further feedback into the product system is considered before these impacts are applied in decision-making. Using this conceptual model, we contrast the traditional mathematical calculation of the life cycle impacts with a new, simpler computational structure where the life cycle impacts are calculated directly as part of the Leontief inverse, treating product flows and environmental flows in parallel, without the need to consider any boundary between economic and environmental activities.

Results and discussion

Our theoretical outline and the numerical example demonstrate that the distinctions and boundaries between product systems and their environment are unnecessary and in some cases obstructive from the perspective of impact assessment, and can therefore be ignored or chosen freely to reflect meaningful distinctions of specific life cycle assessment (LCA) studies. We show that our proposed computational structure is backwards compatible with the current practice of LCA modelling, while allowing inclusion of feedback loops both from the environment to the economy and internally between different impact categories in the impact assessment.

Conclusions

Our proposed computational structure for LCA facilitates consistent, explicit and transparent modelling of the feedback loops between environment and the economy and between different environmental mechanisms. The explicit and transparent modelling, combining economic and environmental information in a common computational structure, facilitates data exchange and re-use between different academic fields.

     

Implicit prioritization in life cycle assessment: text mining and detecting metapatterns in the literature

Purpose

Life cycle assessment aims to evaluate multiple kinds of environmental impact associated with a product or process across its life cycle. Objective evaluation is a common goal, though the community recognizes that implicit valuations of diverse impacts resulting from analytical choices and choice of subject matter are present. This research evaluates whether these implicit valuations lead to detectable priority shifts in the published English language academic LCA literature over time.

Methods

A near-comprehensive investigation of the LCA literature is undertaken by applying a text mining technique known as topic modeling to over 8200 environment-related LCA journal article titles and abstracts published between 1995 and 2014.

Results and discussion

Topic modeling using MALLET software and manual validation shows that over time, the LCA literature reflects a dramatic proportional increase in attention to climate change and a corresponding decline in attention to human and ecosystem health impacts, accentuated by rapid growth of the LCA literature. This result indicates an implicit prioritization of climate over other impact categories, a field-scale trend that appears to originate mostly in the broader environmental community rather than the LCA methodological community. Reasons for proportionally increasing publication of climate-related LCA might include the relative robustness of greenhouse gas emissions as an environmental impact indicator, a correlation with funding priorities, researcher interest in supporting active policy debates, or a revealed priority on climate versus other environmental impacts in the scholarly community.

Conclusions

As LCA becomes more widespread, recognizing and addressing the fact that analyses are not objective becomes correspondingly more important. Given the emergence of implicit prioritizations in the LCA literature, such as the impact prioritization of climate identified here with the use of computational tools, this work recommends the development and use of techniques that make impact prioritization explicit and enable consistent analysis of result sensitivity to value judgments. Explicit prioritization can improve transparency while enabling more systematic investigation of the effects of value choices on how LCA results are used.

     

A life cycle assessment framework combining nutritional and environmental health impacts of diet: a case study on milk

Purpose

While there has been considerable effort to understand the environmental impact of a food or diet, nutritional effects are not usually included in food-related life cycle assessment (LCA).

Methods

We developed a novel Combined Nutritional and Environmental Life Cycle Assessment (CONE-LCA) framework that evaluates and compares in parallel the environmental and nutritional effects of foods or diets. We applied this framework to assess human health impacts, expressed in Disability Adjusted Life Years (DALYs), in a proof-of-concept case study that investigated the environmental and nutritional human health effects associated with the addition of one serving of fluid milk to the present average adult US diet. Epidemiology-based nutritional impacts and benefits linked to milk intake, such as colorectal cancer, stroke, and prostate cancer, were compared to selected environmental impacts traditionally considered in LCA (global warming and particulate matter) carried to a human health endpoint.

Results and discussion

Considering potential human health effects related to global warming, particulate matter, and nutrition, within the context of this study, findings suggest that adding one serving of milk to the current average diet could result in a health benefit for American adults, assuming that existing foods associated with substantial health benefits are not substituted, such as fruits and vegetables. The net health benefit is further increased when considering an iso-caloric substitution of less healthy foods (sugar-sweetened beverages). Further studies are needed to test whether this conclusion holds within a more comprehensive assessment of environmental and nutritional health impacts.

Conclusions

This case study provides the first quantitative epidemiology-based estimate of the complements and trade-offs between nutrition and environment human health burden expressed in DALYs, pioneering the infancy of a new approach in LCA. We recommend further testing of this CONE-LCA approach for other food items and diets, especially when making recommendations about sustainable diets and food choices.

     

From behind the curtain: talking about values in LCA

Purpose

Practitioners of life cycle assessment (LCA) acknowledge that more input from social scientists can help advance the cause of life cycle management (LCM). This commentary offers a social science perspective on a long-running question within LCA, namely, how the field should manage not only stakeholders’ values but also those of practitioners themselves.

Methods

More than 60 interviews were conducted with LCA practitioners and their industry clients. Qualitative data were also collected through participant observation at several LCA and LCM conferences, a study of the field’s history, and extensive content and discourse analysis of LCA publications and online forums.

Results and discussion

Results show that LCA practitioners’ values are informed partly by the knowledge acquired through their LCA work. At the same time, LCA standards and professional norms implicitly advise practitioners to keep those values out of their work as much as possible, so as not to compromise its apparent objectivity. By contrast, many social scientists contend openly that value-based judgments, based on “situated knowledge,” can actually enhance the rigor, accountability, and credibility of scientific assessments.

Conclusions

LCA practitioners’ own situated knowledge justifies not only the value choices required by LCA but also their evaluative judgments of contemporary life cycle-based sustainability initiatives. This more critical voice could advance the goals of LCM while also boosting the credibility of LCA more generally.

     

Accounting for inventory data and methodological choice uncertainty in a comparative life cycle assessment: the case of integrated multi-trophic aquaculture in an offshore Mediterranean enterprise

Purpose

Integrated multi-trophic aquaculture (IMTA), growing different species in the same space, is a technology that may help manage the environmental impacts of coastal aquaculture. Nutrient discharges to seawater from monoculture aquaculture are conceptually minimized in IMTA, while expanding the farm economic base. In this study, we investigate the environmental trade-offs for a small-to-medium enterprise (SME) considering a shift from monoculture towards IMTA production of marine fish.

Methods

A comparative life cycle assessment (LCA), including uncertainty analysis, was implemented for an aquaculture SME in Italy. Quantification and simultaneous propagation of uncertainty of inventory data and uncertainty due to the choice of allocation method were combined with dependent sampling to account for relative uncertainties and statistical testing and interpretation to understand the uncertainty analysis results. Monte Carlo simulations were used as a propagation method. The environmental impacts per kilo of fish produced in monoculture and in IMTA were compared. Twelve impact categories were considered. The comparison is first made excluding uncertainty (deterministic LCA) and then accounting for uncertainties.

Results and discussion

Deterministic LCA results evidence marginal differences between the impacts of IMTA and monoculture fish production. IMTA performs better on all impacts studied. However, statistical testing and interpretation of the uncertainty analysis results showed that only mean impacts for climate change are significantly different for both productive systems, favoring IMTA. For the case study, technical variables such as scales of production of the species from different trophic levels, their integration (space and time), and the choice of species determine the trade-offs. Also, LCA methodological choices such as that for an allocation method and the treatment of relative uncertainties were determinant in the comparison of environmental trade-offs.

Conclusions

The case study showed that environmental trade-offs between monoculture and IMTA fish production depend on technical variables and methodological choices. The combination of statistical methods to quantify, propagate, and interpret uncertainty was successfully tested. This approach supports more robust environmental trade-off assessments between alternatives in LCAs with uncertainty analysis by adding information on the significance of results. It was difficult to establish whether IMTA does bring benefits given the scales of production in the case study. We recommend that the methodology defined here is applied to fully industrialized IMTA systems or bay-scale environments, to provide more robust conclusions about the environmental benefits of this aquaculture type in Europe.

     

Accounting for effects of carbon flows in LCA of biomass-based products—exploration and evaluation of a selection of existing methods

Purpose

Life cycle assessment (LCA) has become one of the most widespread environmental assessment tools during the last two decades. However, there are still impacts that are not yet fully integrated, including climate impacts of land use. This study contributes to the development process by testing a selection of recently proposed climate impacts assessment methods, some more focused on the impact of land use and others more focused on a product’s carbon life cycle.

Methods

Several assessment methods have been proposed in recent years, with their development still being in progress. Of these methods, we selected three methods that are more focused on the product’s carbon life cycle, and two methods more focused on the impact of land use. We applied the methods to an LCA study comparing biomass-based polyethylene (PE) packaging via different production routes in order to identify their methodological and practical challenges.

Results and discussion

We found that including the impact of land use and carbon cycles had a profound effect on the results for global warming impact potential. It changed the ranking among the different routes for PE production, sometimes making biomass-based PE worse than the fossil alternative. Especially, the methods accounting for long time lags between carbon emissions and uptake in forestry punished the wood-based routes. Moreover, the variation in the results was considerable, showing that although assessment methods for climate impact can be applied to biomass-based products, their outcomes are not yet robust.

Conclusions

We recommend efforts to harmonize and reconcile different approaches for the assessment of climate impact of biomass-based products with regard to (1) how they consider time, (2) their applicability to both short and long rotation crops and (3) harmonization of concepts and terms used by the methods. We further recommend that all value laden methodological choices that are built into the methods, such as the choice of reference states/points, are made explicit and that the outcomes of different modelling choices are tested.

     

The EcoSpold 2 format—why a new format?

Purpose

This paper introduces the new EcoSpold data format for life cycle inventory (LCI).

Methods

A short historical retrospect on data formats in the life cycle assessment (LCA) field is given. The guiding principles for the revision and implementation are explained. Some technical basics of the data format are described, and changes to the previous data format are explained.

Results

The EcoSpold 2 data format caters for new requirements that have arisen in the LCA field in recent years.

Conclusions

The new data format is the basis for the Ecoinvent v3 database, but since it is an open data format, it is expected to be adopted by other LCI databases. Several new concepts used in the new EcoSpold 2 data format open the way for new possibilities for the LCA practitioners and to expand the application of the datasets in other fields beyond LCA (e.g., Material Flow Analysis, Energy Balancing).

     

Data strategy for environmental assessment of agricultural regions via LCA: case study of a French catchment

Purpose

Various approaches have been carried out to extrapolate environmental assessments of farms to the regional level, some of them oversimplified and thus leading to high uncertainty. Key challenges include selection of a representative sample, construction of a farm/land use typology, the extrapolation strategy and dealing with data limitations. This work proposes a method for addressing these issues by means of statistically supported approaches.

Methods

We applied a novel approach combining a sampling strategy, estimation of farm-level environmental impacts via life cycle assessment (LCA), a farm typology based on principal component analysis, a statistical method for extending the farm sample given data constraints and finally linear extrapolation based on regional production and land use, taking into account the regional import–export balance. The approach was applied to a French case study, the Lieue de Grève catchment in the dairy-intensive Brittany region. A decision flowchart was developed to generalise the approach for similar applications dealing with farm and LCA data constraints. Additionally, innovative farm practices were modelled and their impacts propagated to the regional level.

Results and discussion

The typology developed identified “dairy”, “beef”, “dairy + beef” and “swine” farms as the dominant farm types in the region. While swine farms had the highest mean impacts per hectare, dairy and dairy + beef farms had impacts two to five times as high as those of beef and swine farms, when extrapolated to the entire catchment. Multiple linear regressions based on an extended farm and LCA dataset were used to predict environmental impacts of dairy farms lacking LCA results, thus increasing their sample size before extrapolation. The inclusion of farm and LCA data from a neighbouring region did not contribute to the accuracy of predicted impacts, as determined by comparing them to those of the farm closest to the dairy cluster’s centre, but rather produced significantly larger coefficients of variation. Results of tests of including two extra-regional farm and LCA datasets helped determine decision rules for the decision flowchart. Modelling of innovative agricultural practices yielded regional impacts consistent with previous estimates.

Conclusions

This approach provides a generalisable approach for farm typologies, data handling and regional extrapolation of farm-level LCAs, applicable to estimate environmental impacts of any agricultural area if requirements of a representative farm sample are met. We demonstrate the utility of the method for estimating effects of innovative agricultural practices on a region’s impacts by modelling practices on virtual farms and extrapolating their results.

     

Bridge processes: a solution for LCI datasets independent of background databases

Introduction

New platforms are emerging that enable more data providers to publish life cycle inventory data.

Background

Providing datasets that are not complete LCA models results in fragments that are difficult for practitioners to integrate and use for LCA modeling. Additionally, when proxies are used to provide a technosphere input to a process that was not originally intended by the process authors, in most LCA software, this requires modifying the original process.

Results

The use of a bridge process, which is a process created to link two existing processes, is proposed as a solution.

Discussion

Benefits to bridge processes include increasing model transparency, facilitating dataset sharing and integration without compromising original dataset integrity and independence, providing a structure with which to make the data quality associated with process linkages explicit, and increasing model flexibility in the case that multiple bridges are provided. A drawback is that they add additional processes to existing LCA models which will increase their size.

Conclusions

Bridge processes can be an enabler in allowing users to integrate new datasets without modifying them to link to background databases or other processes they have available. They may not be the ideal long-term solution but provide a solution that works within the existing LCA data model.

     

Uncertainty in LCA case study due to allocation approaches and life cycle impact assessment methods

Purpose

Uncertainty is present in many forms in life cycle assessment (LCA). However, little attention has been paid to analyze the variability that methodological choices have on LCA outcomes. To address this variability, common practice is to conduct a sensitivity analysis, which is sometimes treated only at a qualitative level. Hence, the purpose of this paper was to evaluate the uncertainty and the sensitivity in the LCA of swine production due to two methodological choices: the allocation approach and the life cycle impact assessment (LCIA) method.

Methods

We used a comparative case study of swine production to address uncertainty due to methodological choices. First, scenario variation through a sensitivity analysis of the approaches used to address the multi-functionality problem was conducted for the main processes of the system product, followed by an impact assessment using five LCIA methods at the midpoint level. The results from the sensitivity analysis were used to generate 10,000 independent simulations using the Monte Carlo method and then compared using comparison indicators in histogram graphics.

Results and discussion

Regardless of the differences between the absolute values of the LCA obtained due to the allocation approach and LCIA methods used, the overall ranking of scenarios did not change. The use of the substitution method to address the multi-functional processes in swine production showed the highest values for almost all of the impact categories, except for freshwater ecotoxicity; therefore, this method introduced the greater variations into our analysis. Regarding the variation of the LCIA method, for acidification, eutrophication, and freshwater ecotoxicity, the results were very sensitive. The uncertainty analysis with the Monte Carlo simulations showed a wide range of results and an almost equal probability of all the scenarios be the preferable option to decrease the impacts on acidification, eutrophication, and freshwater ecotoxicity. Considering the aggregate result variation across allocation approaches and LCIA methods, the uncertainty is too high to identify a statistically significant alternative.

Conclusions

The uncertainty analysis showed that performing only a sensitivity analysis could mislead the decision-maker with respect to LCA results; our analysis with the Monte Carlo simulation indicates no significant difference between the alternatives compared. Although the uncertainty in the LCA outcomes could not be decreased due to the wide range of possible results, to some extent, the uncertainty analysis can lead to a less uncertain decision-making by demonstrating the uncertainties between the compared alternatives.

     

A modeling framework to evaluate sustainability of building construction based on LCSA

Purpose

Life cycle sustainability assessment (LCSA) is a method that combines three life cycle techniques, viz. environmental life cycle assessment (LCA), life cycle costing (LCC), and social life cycle assessment (S-LCA). This study is intended to develop a LCSA framework and a case study of LCSA for building construction projects.

Methods

A LCSA framework is proposed to combine the three life cycle techniques. In the modeling phases, three life cycle models are used in the LCSA framework, namely the environmental model of construction (EMoC), cost model of construction (CMoC), and social-impact model of construction (SMoC). A residential building project is applied to the proposed LCSA framework from “cradle to the end of construction” processes to unveil the limitations and future research needs of the LCSA framework.

Results and discussion

It is found that material extraction and manufacturing account for over 90 % to the environmental impacts while they contribute to 61 % to the construction cost. In terms of social impacts, on-site construction performs better than material extraction and manufacturing, and on-site construction has larger contributions to the positive social impacts. The model outcomes are validated through interviews with local experts in Hong Kong. The result indicates that the performance of the models is generally satisfactory.

Conclusions

The case study has confirmed that LCSA is feasible. Being one of the first applications of LCSA on building construction, this study fulfills the current research gap and paves the way for future development of LCSA.

     

Streamlining scenario analysis and optimization of key choices in value chains using a modular LCA approach

Purpose

The environmental performance of products or services is often a result of a number of key decisions that shape their life cycles (e.g., techology choices). This paper introduces a modular LCA approach that is capable of reducing the effort involved in performing scenario analyses and optimization when several key choices along a product’s value chain lead to many alternative life cycles.

Methods

The main idea is that the value chain of a product can be divided into interconnected but exchangeable modules, which together represent a full life cycle. A module is comprised of unit processes from the practitioner’s LCI database. The inputs, outputs, and system boundaries of each module can be tailored to the context of the studied system. Alternatives arise whenever multiple modules produce substitutable products. Unlike in conventional LCI databases, no copies are necessary to represent the same process with different inputs. A module-product matrix is used to store this information. It can be used as a basis for an automated scenario analysis of all alternatives or as an input to an optimization model.

Results and discussion

Our approach is illustrated in two case studies: (1) Passenger car fuel choices are modeled by 15 modules representing 33 alternative value chains for diesel, petrol, natural gas and electric cars. The automated comparison of LCA results indicates that electric mobility is often the preferable option from a climate perspective, but impacts depend strongly on the electricity source. (2) A dynamic optimization model including stocks is built from eight modules to analyze the optimal use of wood for material and energy applications. Results indicate that although direct substitution benefits are higher for energy applications, cascading use of wood can maximize environmental performance over the entire life cycle.

Conclusions

The modular LCA approach permits an efficient modeling and comparison of alternative product life cycles, enabling practitioners to focus on key decisions. It can be applied to exploit a potential that is hidden in LCI databases, which is that they contain many specific inventories but not all useful combinations in the context of scenario analyses. The user-defined level of abstraction that is introduced through modules can be helpful in the communication of LCA results. The modular approach also facilitates the integration of LCA and optimization as well as other industrial ecology methods. An open source software is provided to enable others to apply and further develop our implementation of a modular LCA approach.

     

Choice of land reference situation in life cycle impact assessment

Purpose

Land use life cycle impact assessment is calculated as a distance to target value—the target being a desirable situation defined as a reference situation in Milà i Canals et al.’s (Int J Life Cycle Assess 12(1):2–4, 2007) widely accepted framework. There are several reference situations. This work aims to demonstrate the effect of the choice of reference situation on land impact indicators.

Methods

Various reference situations are reported from the perspective of the object of assessment in land in life cycle assessment (LCA) studies and the modeling choices used in life cycle land impact indicators. They are analyzed and classified according to additional LCA modeling requirements: the type of LCA approach (attributional or consequential), cultural perspectives (egalitarian, hierarchist or individualist), and temporal preference. Sets of characterization factors (CF) by impact pathway, land cover, and region are calculated for different reference situations. These sets of CFs by reference situation are all compared with a baseline set. A case study on different crop types is used to calculate impact scores from different sets of CFs and compare them.

Results and discussion

Comparing the rankings of the CFs from two different sets present inversions from 5% to 35% worldwide. Impact scores of the case study present inversions of 10% worldwide. These inversions demonstrate that the choice of a reference situation may reverse the LCA conclusions for the land use impact category. Moreover, these reference situations must be consistent with the different modeling requirements of an LCA study (approach, cultural perspective, and time preference), as defined in the goal and scope.

Conclusions

A decision tree is proposed to guide the selection of a consistent and suitable choice of reference situation when setting other LCA modeling requirements.

     

Geopolitical-related supply risk assessment as a complement to environmental impact assessment: the case of electric vehicles

Purpose

Introducing a geopolitical-related supply risk (GeoPolRisk) into the life cycle sustainability assessment (LCSA) framework adds a criticality aspect to the current life cycle assessment (LCA) framework to more meaningfully address direct impacts on Natural Resource AoP. The weakness of resource indicators in LCA has been the topic of discussion within the life cycle community for some time. This paper presents a case study on how to proceed towards the integration of resource criticality assessment into LCA under the LCSA. The paper aims at highlighting the significance of introducing the GeoPolRisk indicator to complement and extend the established environmental LCA impact categories.

Methods

A newly developed GeoPolRisk indicator proposed by Gemechu et al., J Ind Ecol (2015) was applied to metals used in the life cycle of an electric vehicle, and the results are compared with an attributional LCA of the same resources. The inventory data is based on the publication by Hawkins et al., J Ind Ecol 17:53–64 (2013), which provides a current, transparent, and detailed life cycle inventory data of a European representative first-generation battery small electric vehicle.

Results and discussion

From the 14 investigated metals, copper, aluminum, and steel are the most dominant elements that pose high environmental impacts. On the other hand, magnesium and neodymium show relatively higher supply risk when geopolitical elements are considered. While, the environmental indicator results all tend to point the same hotspots which arise from the substantial use of resources in the electric vehicle’s life cycle, the GeoPolRisk highlights that there are important elements present in very small amounts but crucial to the overall LCSA. It provides a complementary sustainability dimension that can be added to conventional LCA as an important extension within LCSA.

Conclusions

Resource challenges in a short-term time perspective can be better addressed by including social and geopolitical factors in addition to the conventional indicators which are based on their geological availability. This is more significant for modern technologies such as electronic devices in which critical resources contribute to important components. The case study advances the use of the GeoPolRisk assessment method but does still face certain limitations that need further elaboration; however, directions for future research are promising.

     

Social life cycle assessment of average Irish dairy farm

Purpose

The majority of sustainability studies of dairy farms focused on environmental performance and profitability; however, social aspect has been hardly assessed. This study aims to investigate the social impacts of dairy farm via a case study using a social life cycle assessment framework.

Methods

The assessment was carried out applying the social LCA Guideline by UNEP-SETAC. Nineteen suitable social indicators were selected from four stakeholder categories of the guideline. Characterization and normalization were further developed based on data availability. National farm survey data was used as foreground data for farm activities, supplemented with background data from public database and life cycle working environment (LCWE) data by Gabi database. All indicators were divided into three groups: functional unit-related quantitative indicators, non-functional unit-related quantitative indicators and semi-quantitative indicators.

Results and discussion

Irish dairy farming has positive social impacts on value chain actors and society, predominantly positive impacts for local community and generally positive values for workers. The main negative impacts are health and safety issue, equal opportunity for workers, and safe and healthy living conditions for the local community. Possible actions to improve the social performance include introducing more efficient and robotic milk production systems; applying better handling methods and using real time decision support to operational management for emissions reduction.

Conclusions

This study is the first attempt of social LCA in Ireland. It demonstrated a possible method to carry out SLCA for Irish dairy sector. The results identified the positive and negative social hotspot of dairy farm with recommendation for future improvement.

     

Review: life cycle assessments in Nigeria,Ghana, and Ivory Coast

Purpose

Life cycle assessments (LCAs) are considered common quantitative environmental techniques to analyze the environmental impact of products and/or services throughout their entire life cycle. A few LCA studies have been conducted in West Africa. This study aimed to discuss the availability of LCA (and similar) studies in Nigeria, Ghana, and Ivory Coast.

Methods

An online literature review of reports published between 2000 and 2016 was conducted using the following keywords: “life cycle assessment,” “carbon footprinting,” “water footprinting,” “environmental impact,” “Nigeria,” “Ghana” and “Ivory Coast.”

Results and discussion

A total of 31 LCA and environmental studies in Nigeria, Ghana, and Ivory Coast were found; all but one were conducted after 2008. These were mainly academic and most were publicly available. The industries studied included energy sector, waste management, real estate, food sector, and others such as timber and gold. The minimal number of studies on LCAs and environmental impacts in these West African states could be because companies are failing to promote quantitative environmental studies or studies are kept internally for the use of other assessment techniques. Furthermore, it could be that academic research institutions lack cutting-edge research resources for LCA, environmental impact, carbon, and water footprinting studies.

Conclusions

Further quantitative environmental studies should be conducted in Nigeria, Ghana, and Ivory Coast to increase the understanding of environmental impacts. In these countries, the existence of LCA studies (and by association the localized life cycle inventory (LCI) datasets) is crucial as more companies request this information to feed into background processes.

     

Salinisation impacts in life cycle assessment: a review of challenges and options towards their consistent integration

Purpose

Salinisation is a threat not only to arable land but also to freshwater resources. Nevertheless, salinisation impacts have been rarely and only partially included in life cycle assessment (LCA) so far. The objectives of this review paper were to give a comprehensive overview of salinisation mechanisms due to human interventions, analyse the completeness, relevance and scientific robustness of existing published methods addressing salinisation in LCA and provide recommendations towards a comprehensive integration of salinisation within the impact modelling frameworks in LCA.

Methods

First, with the support of salinisation experts and related literature, we highlighted multiple causes of soil and water salinisation and presented induced effects on human health, ecosystems and resources. Second, existing life cycle impact assessment (LCIA) methods addressing salinisation were analysed against the International Reference Life Cycle Data System analysis grid of the European Commission. Third, adopting a holistic approach, the modelling options for salinisation impacts were analysed in agreement with up-to-date LCIA frameworks and models.

Results and discussion

We proposed a categorisation of salinisation processes in four main types based on salinisation determinism: land use change, irrigation, brine disposal and overuse of a water body. For each salinisation type, key human management and biophysical factors involved were identified. Although the existing methods addressing salinisation in LCA are important and relevant contributions, they are often incomplete with regards to both the salinisation pathways they address and their geographical validity. Thus, there is a lack of a consistent framework for salinisation impact assessment in LCA. In analysing existing LCIA models, we discussed the inventory and impact assessment boundary options. The land use/land use change framework represents a good basis for the integration of salinisation impacts due to a land use change but should be completed to account for off-site impacts. Conversely, the land use/land use change framework is not appropriate to model salinisation due to irrigation, overuse of a water body and brine disposal. For all salinisation pathways, a bottom-up approach describing the environmental mechanisms (fate, exposure and effect) is recommended rather than an empirical or top-down approach because (i) salts and water are mobile and theirs effects are interconnected; (ii) water and soil characteristics vary greatly spatially; (iii) this approach allows the evaluation of both on- and off-site impacts and (iv) it is the best way to discriminate systems and support a reliable eco-design.

Conclusions

This paper highlights the importance of including salinisation impacts in LCA. Much research effort is still required to include salinisation impacts in a global, consistent and operational manner in LCA, and this paper provides the basis for future methodological developments.

     

ONE TWO WE—life cycle management in canteens together with suppliers,customers and guests

Purpose

Private food consumption accounts for 30 % of total environmental impacts caused by the final consumption of Swiss households. The private expenses for gastronomy and hotels account for another 6 %. Therefore, it is necessary to investigate and better understand the environmental impacts of food consumption and the possibilities for a reduction of these impacts. This was the starting point for the collaboration between the canteen operator SV Group, the life cycle assessment (LCA) consultancy ESU-services, the energy supplier ewz and the World Wide Fund for Nature (WWF) in Switzerland focusing on food consumption in canteens.

Methods

In a first step, an LCA study was used to analyse the environmental impacts of about 20 million meals served in 240 canteens in 2011. LCA data for 160 food items were linked to the food amounts of about 10,000 articles purchased in this year. This was supplemented by data on canteen operation and resulted in a full organisational LCA.

Results and discussion

The impacts of food purchases are about four times higher than the direct impacts due to the operation of the canteens. The most important product groups are meat and dairy products. Improvement potentials have been identified within 14 different themes by the project group. They include measures in the canteen operation (e.g. reduction of food waste or energy-efficient appliances); measures in the supply chain, e.g. a reduction of vegetables grown in heated greenhouses; or the abandonment of air-transported products. But also dietary choices such as a reduction of the average amount of meat per meal are considered as an option. The results and recommendations of the detailed LCA as well as information by other partners have been used by the SV Group to develop the programme ONE TWO WE. It assists the customers (companies who commission the operation of canteens in their premises) to reach improved levels of environmental performance. The programme aims for a 20 % cut on GHG emissions after full implementation in the participating canteens.

Conclusions

The programme started successfully with many customers positively convinced by the proposed changes in the provision of canteen meals. An initial reduction of greenhouse gas emissions compared to the baseline was achieved. This LCA study is a good example for the value of calculating a full organisational environmental footprint for a company in the gastronomy sector and for using the results of such a study to bring down the overall environmental impacts.