The concepts of Safe by Design (SbD) and Safe and Sustainable by Design (SSbD) are receiving increasing attention. The definitions of both concepts include the term ‘life cycle’ in combination with... Show moreThe concepts of Safe by Design (SbD) and Safe and Sustainable by Design (SSbD) are receiving increasing attention. The definitions of both concepts include the term ‘life cycle’ in combination with the terms ‘chemical’, ‘material’ and ‘product’, but their meanings are not further elaborated and defined in scholarly publications on SbD/SSbD. Here, we address two research questions: (1) How are the terms chemical, material and product used and defined in the scholarly literature on SbD and SSbD; (2) How are life cycles defined and which are considered in the scholarly literature on SbD/SSbD? We found largely consistent, though still confusing, uses of the terms product, material and chemical and we found four types of life cycles in the reviewed papers. Using consistent definitions of the terms product, material and chemical, we reduce the four types of life cycles found to three types of distinctive life cycles: (1) the life cycle of a product; (2) the life cycle of a chemical in a specific product; (3) the life cycle of a chemical in all its product applications. We discuss the different trade-offs that each of these life cycle approaches canidentify and argue that they are complementary and should preferably all be applied in SbD/SSbD studies. Show less
Why are both A-1${\mathbf{A}}<^>{-1}$ and (I-A)-1${(\mathbf{I}-\mathbf{A})}<^>{-1}$ used in life cycle assessment (LCA) matrix computations? This is a question that, in our experience... Show moreWhy are both A-1${\mathbf{A}}<^>{-1}$ and (I-A)-1${(\mathbf{I}-\mathbf{A})}<^>{-1}$ used in life cycle assessment (LCA) matrix computations? This is a question that, in our experience of teaching LCA, students often wonder about and struggle with. A brief survey of the literature suggests that the question can also confuse experienced LCA practitioners. Here, we seek to unify the computational structures of the two LCA approaches to achieve greater clarity and consistency, especially to make them easier to teach. We first show how small but crucial differences in the set-up of the two approaches lead to the use of A$\mathbf{A}$ versus I-A$\mathbf{I}-\mathbf{A}$. Then, we discuss the options to unify the presentations in a coherent way. We do not prescribe one way or the other. A larger point we hope to stress is the importance of unification, which may have both pedagogical and methodological benefits. Show less
Introduction Many methodological papers report a comparison of methods for LCA, for instance comparing different impact assessment systems, or developing streamlined methods. A popular way to do so... Show moreIntroduction Many methodological papers report a comparison of methods for LCA, for instance comparing different impact assessment systems, or developing streamlined methods. A popular way to do so is by studying the differences of results for a number of products. We refer to such studies as quasi-empirical meta-comparisons. Review of existing approaches A scan of the literature reveals that many different methods and indicators are employed: contribution analyses, Pearson correlations, Spearman correlations, regression, significance tests, neural networks, etc. Critical discussion We critically examine the current practice and conclude that some of the widely used methods are associated with important deficits. A new approach Inspired by the critical analysis, we develop a new approach for meta-comparative LCA, based on directional statistics. We apply it to several real-world test cases, and analyze its performance vis-a-vis traditional regression-based approaches. Conclusion The method on the basis of directional statistics withstands the tests of changing the scale and unit of the training data. As such, it holds a promise for improved method comparisons. Show less
Over the past years, an increasing number of scholarly papers have used the planetary boundaries (PBs) within life cycle assessment (LCA) to determine if the life cycle impacts of a product system... Show moreOver the past years, an increasing number of scholarly papers have used the planetary boundaries (PBs) within life cycle assessment (LCA) to determine if the life cycle impacts of a product system fit within those PBs and thereby establish the absolute sustainability of the product system. This type of LCA is nowadays coined as LCA-based Absolute Environmental Sustainability Assessment (AESA). "Absolute" thereby refers to methods enabling the comparison of environmental impacts of products, companies, nations, and so on, with an assigned share of environmental carrying capacity for various impact categories. A recent review of LCA-based AESA methods and their applications characterized 47 studies "according to their intended application, impact categories, basis of carrying capacity estimates, spatial differentiation of environmental model and principles for assigning carrying capacity." However, the review and the majority of studies reviewed did not, or only to a limited extent, discuss potential temporal issues of assigning carrying capacity to product systems. Several of the carrying capacity estimates have a time dimension while LCA results lack a time dimension. In this article, we show that assigning PBs to product systems is only technically possible when adopting several fundamental though unrealistic assumptions, and conclude that even product LCA-based AESA is relative. This should not withhold scholars from developing approaches applying the PBs in LCA, but it should prevent them from claiming and using the term "absolute." Show less
Gennaria diphylla (Link) Parl. is a terrestrial, inconspicuous green orchid. Its distribution includes the central and western Mediterranean region as well as the Canary Islands and Madeira.... Show moreGennaria diphylla (Link) Parl. is a terrestrial, inconspicuous green orchid. Its distribution includes the central and western Mediterranean region as well as the Canary Islands and Madeira. Investigations on its pollination biology are scarce. In literature, there are mentions of autogamy and of allogamy. Pollination and pollen import and export were studied on Tenerife and Madeira. The investigations showed autogamy plays a less important role than thought, although a caging experiment showed that the species is well capable of self-pollination. The orchid is pollinated by a variety of small moths, especially of the families Geometridae, Pyralidae and Crambidae. It is flowering in a period when few other plants flower, so there is little competition for pollinators. Complemented by autogamy this seems to be a successful strategy, as the species shows a relatively high average fruit set of 73 %. Show less
Limited and uneven distributed water resources have become one of the main obstacles to China's sustainable development, and the "virtual water hypothesis" (VWH) is expected to help mitigate water... Show moreLimited and uneven distributed water resources have become one of the main obstacles to China's sustainable development, and the "virtual water hypothesis" (VWH) is expected to help mitigate water stress. This study discusses the virtual water transfer pattern and water resources stress in China from the VWH perspective. Economic sectors in China are divided into land-dependent sectors and non-land-dependent sectors according to their dependence on specific local land types. Furthermore, the water resources withdrawal and utilization corresponding to these sectors are divided into land-dependent water resources (LDW) and non-land-dependent water resources (NLDW). Results show that the virtual LDW flows from economically poor to relatively developed regions, while the virtual NLDW flows in the opposite direction. LDW dominates Chinese water stress (78.2%) and virtual water flow (74.5%). Furthermore, the virtual water dominated by LDW ameliorates national water stress (the population under unsustainable water stress declined by 0.21 billion) but aggravates the imbalance of water resources between North and South. The transfer of virtual NLDW alleviates this imbalance slightly. Suitable land conditions play a decisive role in LDW withdrawal, which then cannot be replenished by virtual water. However, the withdrawal and transfer of NLDW are flexible, which should be a focus. The results point out that the possibility of water-rich regions as virtual water exporters is the key to alleviating the North-South water resource imbalance in China with VWH theory. Improvement of land productivity and water efficiency can be helpful to alleviate water stress. These findings may provide new insight into China's virtual water transfer pattern from the VWH perspective. Show less
In economics, opportunity cost is defined as the benefit foregone by choosing another course of action. Considering opportunity costs enables the improved handling of trade-offs to better support... Show moreIn economics, opportunity cost is defined as the benefit foregone by choosing another course of action. Considering opportunity costs enables the improved handling of trade-offs to better support strategic decision-making. We introduce the concept of opportunity cost into life cycle assessment (LCA). In our framework, opportunity cost extends the system expansion paradigm to support better alignment with a circular economy (CE). Opportunity cost thinking is considered to be most useful for the efficient allocation of scarce economic capital for the creation of economic value. In the environmental domain, we use such thinking to account for the implications of 'wasting waste'. In this paper, we consider a case of treated wastewater sludge being used as a source of nutrients as a vehicle to study the points at which LCA can support a CE. Our conclusions, however, have wider repercussions because there are many more situations in which product systems are analytically demarcated from the web of connections in which they are embedded. Show less
For several decades structural modelling has assisted decision makers with the cognitive burden of exploring and interpreting complex situations. Three well-known techniques - labelled collectively... Show moreFor several decades structural modelling has assisted decision makers with the cognitive burden of exploring and interpreting complex situations. Three well-known techniques - labelled collectively here as semi-quantitative problem structuring and modelling (SPSM) - include ISM (Interpretive Structural Modelling); MICMAC (Matrice d'Impacts Croises-Multiplication Appliquee a un Classement); and DEMATEL (DEcision MAking Trial and Evaluation Laboratory). SPSM approaches pioneered the joint application of graph-theoretical principles and human-computer interaction. Yet today a template-style research approach prevails, focusing on the application context rather than seeking to advance or critically assess the individual techniques in their own right. This paper develops a unifying methodological view of SPSM, currently missing in the literature, by comparing and contrasting - for each technique - analytical and procedural aspects typically taken for granted. The paper's findings highlight: (1) Previously unnoticed overlaps between techniques that up to now have been deemed mutually exclusive, and incongruences between those that are often applied jointly; 2) Potential issues that arise when key analytical principles of SPSM are either applied uncritically or dispensed with altogether; 3) The need to leverage human-computer interaction, a prominent aspect in early SPSM research that is now surprisingly neglected. These findings are illustrated by a review of SPSM applications in the context of supply chain risk management. Show less
Dairy farms are systems with multiple dependent variables whose practices influence their economic and environmental performances. Decisions made and actions taken to improve environmental... Show moreDairy farms are systems with multiple dependent variables whose practices influence their economic and environmental performances. Decisions made and actions taken to improve environmental performances of dairy farms carry the risk of decreasing farm profitability. Correlations among multiple variables must therefore be considered to reliably assess risks of improving environmental performances of farms. We applied copula models to a dataset of conventional dairy farms surveyed in France to decscribe relationships among their characteristics, such as forage dry matter (DM) production, milk production, and greenhouse gas (GHG) emissions. By modeling relationships among farm characteristics, copula models can identify the characteristics' joint distributions, unlike other statistical methods. For dairy farms, copula models are useful for estimating probabilities of reaching a milk production goal or not exceeding a regulatory emission limit as a function of forage production. For instance, when a farm produced at least 4,500 kg DM/livestock unit/year of maize silage, the probability of producing at least 7,000 l milk/cow/year was 75%, while the probability of emitting less than 7,000 kg CO2 eq./farm/year (a value close to the mean of 6669 kg CO2 eq./farm/year for all of the farms) was 48%. When the same amount of grass from pasture was produced, these probabilities changed to 48% and 78%, respectively (i.e., decreased probability of reaching a production goal, but increased probability of not exceeding an emission threshold). Farmers must make trade-offs, since increased milk production goals are likely to increase GHG emissions per farm and/or reduce GHG emission intensities per l of milk, but are less likely to be reached for a given amount of forage DM. By providing information about relationships among farm characteristics that other statistical approaches cannot, copula models are useful for investigating these trade-offs. Show less
Pramanik, D.; Spaans, M.; Kranenburg, T.; Bogarin Chaves, D.G.; Heijungs, R.; Lens, F.P.; ... ; Gravendeel, B. 2022
Phalaenopsis is an important ornamental pot plant for the global horticultural market. The inflorescences of Phalaenopsis horticultural hybrids require support from a stick during plant... Show morePhalaenopsis is an important ornamental pot plant for the global horticultural market. The inflorescences of Phalaenopsis horticultural hybrids require support from a stick during plant cultivation because of the weight of multiple large flowers. Developing a horticultural hybrid with a sufficiently lignified inflorescence stem that does not require additional support could be a way to reduce the costs of production. This study aimed to (i) determine the orientation and degree of lignification in the inflorescence stem of different species and horticultural hybrids of Phalaenopsis and investigate whether these lignification patterns follow any (ii) topological or (iii) phylogenetic pattern of interest to further explore in genetic precision breeding. Inflorescences of comparable devel- opmental stages of six species and 17 horticultural hybrids of flowering Phalaenopsis orchids were sampled. The orientation of the inflorescence varied from erect, sub-erect, arching, to pendant. The degree of lignification was measured with ImageJ using stained microscopic tissue sections and statistically analyzed. A molecular phylogeny of the species of Phalaenopsis was reconstructed based on plastid and nuclear ribosomal DNA sequences to analyze phylogenetic patterns. Our results show a significant difference in the degree of lignification between the different Phalaenopsis species and hybrids, between peduncle and rachis, and among the six different inflorescence positions analyzed. We found a positive correlation between inflorescence orientation and the proportion of lignified area per total stem area and the proportional thickness of the lignified fiber walls in the peduncle. We conclude that the degree of lignification is heritable, as we observed among our sample size a higher positive correlation between stem lignification variables among closely related taxa compared to more distantly related ones. However, a larger species sampling is needed to further validate our results. Show less
Understanding the spatiotemporal patterns of carbon footprints (CFs) of grains production is important to formulate regional heterogeneous greenhouse gas (GHG) mitigation strategies. This study... Show moreUnderstanding the spatiotemporal patterns of carbon footprints (CFs) of grains production is important to formulate regional heterogeneous greenhouse gas (GHG) mitigation strategies. This study evaluates the CFs, farm CFs (FCFs: CFs of per unit area), and production CFs (PCFs: CFs of per unit yield) of main grains production in China based on a new scale data set: agricultural statistics data of over 300 prefecture-level regions. A comparison of CFs of main grains production between main producing area (MPA) and non-main producing area (NMPA) are firstly discussed on a totally new scale. Results show that the CFs of main grains production of MPA accounts for 54-57% of country's total although the area of farmland of MPA only accounts for 42%. The PCF and FCF of rice production are higher in MPA, while those of wheat and maize production are lower in MPA. It implies that there are less GHG emission of rice (main paddy grain) productions in NMPA and less GHG emission of wheat and maize (main dryland grains) production in MPA. In additional, the PCF of rice shows growth, while that of wheat and maize shows decline from 2008 to 2017. The growth of PCF of rice is mainly driven by the rise of PCF in MPA. Findings are expected to improve the understanding patterns of China's CF of main grains production and subsequently contribute to GHG mitigation. Show less
Cucurachi, S.; Blanco Rocha, C.F.; Steubing, B.R.P.; Heijungs, R. 2021
Life cycle assessment (LCA) models and databases have increased in size, resolution, and complexity, requiring analysts to rely on an ever-increasing number of uncertain model inputs. Such... Show moreLife cycle assessment (LCA) models and databases have increased in size, resolution, and complexity, requiring analysts to rely on an ever-increasing number of uncertain model inputs. Such increased complexity calls for systematic approaches to assessing the uncertainty of the output results of LCA models and the sensitivity of LCA model outputs to the model's uncertain inputs. In this contribution, we provide a theoretical basis and present a practical software implementation that combines uncertainty analysis and moment-independent global sensitivity analysis, which can be readily applied to full-scale LCA models. We implemented our approach in the Activity-Browser open source LCA software and it is made available for use in LCA studies. We demonstrate the approach and software implementation with a case study of crystalline silicon photovoltaics. Show less
A continuous growth of international trade, especially between developing countries, has greatly increased carbon dioxide (CO2) emissions associated with energy consumption over the past two... Show moreA continuous growth of international trade, especially between developing countries, has greatly increased carbon dioxide (CO2) emissions associated with energy consumption over the past two decades. Given the more intensified intraregional cooperation and trade within the Belt and Road Initiative (BRI), this study aims to trace the imbalance of CO2 embodied in trade between nations in BRI and the rest of the world, providing new insights into the drivers of emissions growth by contrasting consumption, production and technological differences-based perspectives. Results indicate that the BRI contributed to over 50% of global carbon footprint and 92% of its increase in 1995–2015. The BRI was a net exporter of trade-embodied emissions, whose technological-adjusted carbon footprint remained remarkably large due to comparatively high carbon intensity. Geographically, carbon leakage has gradually moved from China and India to other BRI countries, especially to Southeast Asia, West Asia and Africa. Technological change was the key driver of emissions reduction, followed by the change in industrial structure. The growth in final demand per capita was the most important driver for the growth of CO2 emissions in BRI. Improving carbon efficiency remains a critical step for BRI nations to slow down not only emissions growth but also carbon leakage. The paper managed to provide novel insights into the carbon leakage in BRI by contrasting the consumption, production and technological differences-based perspectives, thus being able to better inform policymakers on region-specific low-carbon transition and global climate governance. Show less
