Emerging approaches, challenges and opportunities in life cycle assessment

Environmental, Economic and Social Impact Assessment: Study of Bridges in China's Five Major Economic Regions

The construction industry of all countries in the world is facing the issue of sustainable development. How to make effective and accurate decision-making on the three pillars (Environment; Economy; Social influence) is the key factor. This manuscript is based on an accurate evaluation framework and theoretical modelling. Through a comprehensive evaluation of six cable-stayed highway bridges in the entire life cycle of five provinces in China (from cradle to grave), the research shows that life cycle impact assessment (LCIA), life cycle cost assessment (LCCA), and social impact life assessment (SILA) are under the influence of multi-factor change decisions. The manuscript focused on the analysis of the natural environment over 100 years, material replacement, waste recycling, traffic density, casualty costs, community benefits and other key factors. Based on the analysis data, the close connection between high pollution levels and high cost in the maintenance stage was deeply promoted, an innovative comprehensive evaluation discrete mathematical decision-making model was established, and a reasonable interval between gross domestic product (GDP) and sustainable development was determined.

Life-Cycle Assessment of the Wastewater Treatment Technologies in Indonesia’s Fish-Processing Industry

In this paper, a comprehensive life-cycle assessment (LCA) is carried out in order to evaluate the multiple environmental-health impacts of the biological wastewater treatment of the fish-processing industry throughout its life cycle. To this aim, the life-cycle impact assessment method based on endpoint modeling (LIME) was considered as the main LCA model. The proposed methodology is based on an endpoint modeling framework that uses the conjoint analysis to calculate damage factors for human health, social assets, biodiversity, and primary production, based on Indonesia’s local data inventory. A quantitative microbial risk assessment (QMRA) is integrated with the LIME modeling framework to evaluate the damage on human health caused by five major biological treatment technologies, including chemical-enhanced primary clarification (CEPC), aerobic-activated sludge (AS), up-flow anaerobic sludge blanket (UASB), ultrafiltration (UF) and reverse osmosis (RO) in this industry. Finally, a life-cycle costing (LCC) is carried out, considering all the costs incurred during the lifetime. The LCA results revealed that air pollution and gaseous emissions from electricity consumption have the most significant environmental impacts in all scenarios and all categories. The combined utilization of the UF and RO technologies in the secondary and tertiary treatment processes reduces the health damage caused by microbial diseases, which contributes significantly to reducing overall environmental damage.

Assessing and Forecasting Cybersecurity Impacts

Cyberattacks constitute a major threat to most organizations. Beyond financial consequences, they may entail multiple impacts that need to be taken into account when making risk management decisions to allocate the required cybersecurity resources. Experts have traditionally focused on a technical perspective of the problem by considering impacts in relation with the confidentiality, integrity, and availability of information. We adopt a more comprehensive approach identifying a broader set of generic cybersecurity objectives, the corresponding set of attributes, and relevant forecasting and assessment models. These are used as basic ingredients for decision support in cybersecurity risk management.

Assessing the environmental performance for more local and more circular biowaste management options at city-region level

Biomass, biobased materials and food waste are considered priority areas for Europe's transition towards a circular economy (CE). Waste management is a central activity for this transition and offers multiple CE implementation options which should be evaluated from environmental perspective. The purpose of this work was to analyze the environmental consequences when redirecting biowaste flows from conventional to more circular management systems and to identify the CE option with the best environmental performance. We were particularly interested in studying the combined management of green and food waste, analyzing the challenges when introducing separate collection and different treatment processes, and evaluating the substitution potential for by-products. To determine environmental impacts, we performed a life cycle assessment (LCA) based on local data. Following the purpose analyzing a change in the system, we applied a consequential LCA and compared impacts from processes that are replaced with impacts from alternative management options such as co-composting, anaerobic digestion (AD) and decentralized composting. The LCA results show clear advantages for impacts on ecosystems and resource use for the local AD system with separate combined collection. The decentralized system shows reductions in resource use, whereas the industrial co-composting system has higher or similar impacts than the baseline scenario. We conclude that local systems with combined food and green waste management can show benefits if process emissions are properly managed and if by-products are used in applications with high substitution potentials. However, a change towards a CE does not necessarily result in environmental benefits. Our research highlights the complexity of biowaste systems and proposes a novel combination of local data, databases and models to handle this issue. With this research we are further contributing to the understanding of the combined management of food and green waste, which is a relevant, but so far under-researched, management option for cities.

Sprouting "sustainability" in chemical sciences curriculum

The purpose of this paper is to present a new viewpoint on how the curricula for higher education chemistry courses can be restructured, so that students understand the various dimensions of the sustainability concept and are equipped to work chemical sciences in a profitable, clean and societal friendly way, that is synthesis of materials (which collates CHNOPS-atomic symbols) in desired architecture and disperse them after their intended use, back into their natural reservoirs. A very novel idea of "sustainable chemical science facility", encompassing a teaching module capable of imparting strong fundamental Chemistry concepts, a virtual environment for undergoing the basic industrial training and a production unit with modular reactors for resource funding is proposed here. Often research is restricted to academic qualification, and a substantial band gap exists between the microscopic realm of academic research and the macroscopic domain of industrial chemistry, which thrives on research application. This band gap can be overcome by arming young chemists with training, tools and experience to possess complete control (synthetic and functional) on the materials they produce. The conceptual facility if turned into reality will definitely be the right step towards achieving materials with sustainable functionalities. We will have learning, training and production under one roof. Students will receive theoretical, practical and real-life experience of the production in industries, making them efficiently employable at a very young age. The idea is to bridge some critical engineering concepts with core chemistry, but with a clear distinction between chemical reactor engineering and core chemistry. This paper is a brainchild of the author and is more of a policy paper, needed to be elaborately discussed in academic and industrial forums.

Addressing temporal considerations in life cycle assessment

In life cycle assessment (LCA), temporal considerations are usually lost during the life cycle inventory calculation, resulting in an aggregated "snapshot" of potential impacts. Disregarding such temporal considerations has previously been underlined as an important source of uncertainty, but a growing number of approaches have been developed to tackle this issue. Nevertheless, their adoption by LCA practitioners is still uncommon, which raises concerns about the representativeness of current LCA results. Furthermore, a lack of consistency can be observed in the used terms for discussions on temporal considerations. The purpose of this review is thus to search for common ground and to identify the current implementation challenges while also proposing development pathways. This paper introduces a glossary of the most frequently used terms related to temporal considerations in LCA to build a common understanding of key concepts and to facilitate discussions. A review is also performed on current solutions for temporal considerations in different LCA phases (goal and scope definition, life cycle inventory analysis and life cycle impact assessment), analysing each temporal consideration for its relevant conceptual developments in LCA and its level of operationalisation. We then present a potential stepwise approach and development pathways to address the current challenges of implementation for dynamic LCA (DLCA). Three key focal areas for integrating temporal considerations within the LCA framework are discussed: i) define the temporal scope over which temporal distributions of emissions are occurring, ii) use calendar-specific information to model systems and associated impacts, and iii) select the appropriate level of temporal resolution to describe the variations of flows and characterisation factors. Addressing more temporal considerations within a DLCA framework is expected to reduce uncertainties and increase the representativeness of results, but possible trade-offs between additional data collection efforts and the increased value of results from DLCAs should be kept in mind.

The U.S. consumer phosphorus footprint: where do nitrogen and phosphorus diverge?

Phosphorus (P) and nitrogen (N) are essential nutrients for food production but their excess use in agriculture can have major social costs, particularly related to water quality degradation. Nutrient footprint approaches estimate N and P release to the environment through food production and waste management and enable linking these emissions to particular consumption patterns. Following an established method for quantifying a consumer-oriented N footprint for the United States (U.S.), we calculate an analogous P footprint and assess the N:P ratio across different stages of food production and consumption. Circa 2012, the average consumer's P footprint was 4.4 kg P capita^-1 yr^-1 compared to 22.4 kg N capita^-1 yr^-1 for the food portion of the N footprint. Animal products have the largest contribution to both footprints, comprising >70% of the average per capita N and P footprints. The N:P ratio of environmental release based on virtual nutrient factors (kilograms N or P per kilogram of food consumed) varies considerably across food groups and stages. The overall N:P ratio of the footprints was lower (5.2 by mass) than for that of U.S. food consumption (8.6), reinforcing our finding that P is managed less efficiently than N in food production systems but more efficiently removed from wastewater. While strategies like reducing meat consumption will effectively reduce both N and P footprints by decreasing overall synthetic fertilizer nutrient demands, consideration of how food production and waste treatment differentially affect N and P releases to the environment can also inform eutrophication management.

Characterizing Land Use Impacts on Functional Plant Diversity for Life Cycle Assessments

Decision support tools such as life cycle assessment (LCA) increasingly aim to account for impacts on biodiversity. While taxonomic measures like species richness have been implemented, they do not fully grasp the impacts on ecosystem functioning. Functional diversity, derived from the species' traits, is more representative of ecosystem processes. This study provides a framework for developing characterization factors for functional diversity as affected by land use. It exploits the large databases on plant traits and species composition that have recently become available and allow bringing biodiversity impact assessment to the next level. Three functional diversity indices therein describe different aspects of functional diversity, namely richness, evenness, and divergence. Applying our framework to Germany as a proof of concept, we show significant losses in functional plant diversity when converting natural forests to agricultural land use. Consistently across different forests and agricultural systems, functional richness decreases steeply and functional divergence moderately upon occupation. In contrast, functional evenness exhibits opposite trends. The resulting characterization factors are likely to be representative of temperate regions. The framework is flexible and applicable to larger scales and other impact categories. As such, it facilitates harmonizing biodiversity impact assessments and better represents ecosystem functioning by incorporating functional diversity.

Environmental impacts of introducing cable cars in the Andean landscape: A case study for Kuelap, Peru

Cable cars have slowly become a popular means of transport beyond their classical use at ski resorts. In Latin America their use has thrived to access archaeological sites in the Andes, but also in urban environments for mass transit. Despite some apparent benefits of these systems, the current literature is scarce in terms of quantifying the environmental profile of cable cars. Hence, their environmental performance as compared to other means of transport remains essentially unexplored. Therefore, the main objective of this study was to provide a comparative environmental analysis, using Life Cycle Assessment (LCA) methodology, of the two existing transport methods to visit the Kuelap Archaeological Complex, in northern Peru: a recently built cableway system and the alternative unpaved winding road. An attributional LCA perspective was performed for several impact categories, including global warming and particulate matter formation. In addition, a scenario analysis and an uncertainty analysis, using Monte Carlo simulation, were conducted to account for deterministic and stochastic results interpretation. Results demonstrated that succulent environmental benefits are attained when cable cars substitute road transport in complex Andean orographic conditions. However, the rebound effects of reducing traveling times significantly, as well as social and biodiversity aspects, should be analyzed in further depth to complement the environmental analysis.

Sustainable utilization of crop residues for energy generation: A life cycle assessment (LCA) perspective

Modernization in the crop cultivation and development of high yielding varieties resulted in increased crop residues. A large portion of crop residues is not handled appropriately, which leads to environmental burden on society. The crop residues are rich in organic substances, which can be better utilized for various purposes, including energy generation. The utilization of crop residues for energy generation has partially contributed to resolve the inappropriate handling practices, thus reducing their environmental impacts. Life cycle assessment (LCA) is used as a tool to investigate environmental sustainability and can be explored to integrate with social and economic effects to quantify environmental impacts for energy generation from crop residues. This review will provide a comprehensive understanding on LCA inference for decision support to policy-makers and different relevant choices to various applications for sustainable energy generation from crop residues.

Energy System Pathways with Low Environmental Impacts and Limited Costs: Minimizing Climate Change Impacts Produces Environmental Cobenefits and Challenges in Toxicity and Metal Depletion Categories

Environmental indicators based on the life cycle assessment method are integrated into an energy system model. This integration allows for the generation of comprehensive environmental assessments of future energy systems and for determining energy scenarios with less environmental impacts and moderate cost increases. In Switzerland, which is used as a case study to demonstrate the feasibility of our approach, it is possible to generate pathways with a 5% cost increase on the cost-optimal situation, causing an impact score for climate change that is 2% higher than the minimum feasible solution. The minimization of life-cycle impacts on climate change generates substantial environmental cobenefits with regard to human health, air pollution, ozone depletion, acidification, and land transformation. However, this minimization also creates trade-offs that exacerbate the effects of metal depletion and human toxicity caused by upstream extraction and manufacturing linked to technologies such as solar panels and electric vehicles. Finally, ambitious reduction targets of 95% direct (i.e., within the country) CO₂ emissions for the year 2050 might still result in substantial climate change impacts should emissions embodied in the infrastructure and upstream supply chain not be jointly mitigated jointly.

Life cycle assessment of nutrient recycling from wastewater: A critical review

Recovering resources from wastewater systems is increasingly being emphasised. Many technologies exist or are under development for recycling nutrients such as nitrogen and phosphorus from wastewater to agriculture. Planning and design methodologies are needed to identify and deploy the most sustainable solutions in given contexts. For the environmental sustainability dimension, life cycle assessment (LCA) can be used to assess environmental impact potentials of wastewater-based nutrient recycling alternatives, especially nitrogen and phosphorus recycling. This review aims to evaluate how well the LCA methodology has been adapted and applied for assessing opportunities of wastewater-based nutrient recycling in the form of monomineral, multimineral, nutrient solution and organic solid. We reviewed 65 LCA studies that considered nutrient recycling from wastewater for agricultural land application. We synthesised some of their insights and methodological practices, and discussed the future outlook of using LCA for wastewater-based nutrient recycling. In general, more studies suggested positive environmental outcomes from wastewater-based nutrient recycling, especially when chemical inputs are minimised, and source separation of human excreta is achieved. The review shows the need to improve methodological consistency (e.g., multifunctionality, fertiliser offset accounting, contaminant accounting), ensure transparency of inventory and methods, consider uncertainty in comparative LCA context, integrate up-to-date cross-disciplinary knowledge (e.g., agriculture science, soil science) into LCA models, and consider the localised impacts of recycled nutrient products. Many opportunities exist for applying LCA at various scales to support decisions on wastewater-based nutrient recycling - for instance, performing "product perspective" LCA on recycled nutrient products, integrating "process perspective" LCA with other systems approaches for selecting and optimising individual recovery processes, assessing emerging nutrient recovery technologies and integrated resource recovery systems, and conducting systems analysis at city, national and global level.

Sustainability and Life Cycle Assessment in Industrial Biotechnology: A Review of Current Approaches and Future Needs

The development and implementation of industrial biotechnology (IB) is associated with high expectations for reductions of environmental impacts and risks, particularly in terms of climate change and fossil resource depletion, positive socioeconomic effects, hopes for new competitive products and processes, and development in rural areas. However, not all products and processes are really advantageous with regard to sustainability criteria, and not all are economically successful and accepted by stakeholders. Sustainability and life cycle assessment can play an important role to assess IB products and processes, often accompanying development processes from the early stages onwards. Such assessments can identify key factors regarding sustainability criteria, enable a determination of both product and process performance, or aid in prospectively estimating such performance and its consequences. Thus, development processes, investment decisions, policymaking, and the communication with stakeholders can be supported. This contribution reviews the field of sustainability and life cycle assessment in IB. We explore relevant literature from a methodical and application perspective and categorise suitable methodologies, methods, and tools. We characterise IB from an assessment perspective and indicate challenges, discuss approaches to address these, and identify possible fields of future research. Thus, students, researchers, and practitioners in the field of IB will obtain an up-to-date overview, references to relevant fields of literature, and guidance for own studies in this important and fast-emerging topic.

Life Cycle Assessment for the Design of Chemical Processes, Products, and Supply Chains

Design in the chemical industry increasingly aims not only at economic but also at environmental targets. Environmental targets are usually best quantified using the standardized, holistic method of life cycle assessment (LCA). The resulting life cycle perspective poses a major challenge to chemical engineering design because the design scope is expanded to include process, product, and supply chain. Here, we first provide a brief tutorial highlighting key elements of LCA. Methods to fill data gaps in LCA are discussed, as capturing the full life cycle is data intensive. On this basis, we review recent methods for integrating LCA into the design of chemical processes, products, and supply chains. Whereas adding LCA as a posteriori tool for decision support can be regarded as established, the integration of LCA into the design process is an active field of research. We present recent advances and derive future challenges for LCA-based design.

Potential formation of PCDD/Fs in triclosan wastewater treatment: An overall toxicity assessment under a life cycle approach

Wastewater may contain a diverse group of unregulated pollutants known as emerging pollutants, such as pharmaceuticals and personal care products (PPCPs). Triclosan (TCS) is a personal care product widely used as an antiseptic or preservative in cosmetics, hand wash, toothpaste and deodorant soaps. Advanced oxidation processes (AOPs) have been used as effective and alternative treatments for complex wastewater. However, an important criterion for the assessment of AOPs and their operation conditions could be the potential formation of new toxic secondary products, such as polychlorinated dibenzo-p-dioxins and furans (PCDD/Fs), especially when emerging pollutants are present in the media. If these are omitted from environmental management studies, the real environmental impacts of a WWTPs (wastewater treatment plants) may be underestimated. Consequently, the current study aims to evaluate the environmental impacts derived from electrooxidation (EOX), one of the most effective oxidation technologies, of emerging pollutants using Life Cycle Assessment. The analyses were performed for the treatment of effluents containing TCS, firstly without considering the formation of PCDD/Fs and, thereafter, considering the effects of these compounds. Total toxicity, calculated through different methods and corresponding impact factors, were evaluated for each stage of the process when different electrolytes are used, including PCDD/Fs formation. Finally, a sensitivity analysis was carried out to study i) the effect of the TCS initial concentration on the environmental impacts associated to ecotoxicity for the different life cycle methods and ii) the influence of changing the organic pollutant on PCDD/Fs formation employing 2-chlorophenol (2-CP). As a result, LCIA methods demonstrate that they are not fully adapted to the computation of PCDD/Fs in the water compartment, since only 2,3,7,8-tetraclorodibenzo-p-dioxina (2,3,7,8-TCDD) is present as a substance in the impact categories assessed, ignoring the remaining list of PCDD/Fs.

Mitigation Life Cycle Assessment: Best Practices from LCA of Energy and Water Infrastructure That Incurs Impacts to Mitigate Harm

Climate change will require societal-scale infrastructural changes. Balancing priorities for water, energy, and climate will demand that approaches to water and energy management deviate from historical practice. Infrastructure designed to mitigate environmental harm, particularly related to climate change, is likely to become increasingly prevalent. Understanding the implications of such infrastructure for environmental quality is thus of interest. Environmental life cycle assessment (LCA) is a common sustainability assessment tool that aims to quantify the total, multicriteria environmental impact caused by a functional unit. Notably, however, LCA quantifies impacts in the form of environmental “costs” of delivering the functional unit. In the case of mitigation infrastructures, LCA results can be confusing because they are generally reported as the harmful impacts of performing mitigation rather than as net impacts that incorporate benefits of successful mitigation. This paper argues for defining mitigation LCA as a subtype of LCA to facilitate better understanding of results and consistency across studies. Our recommendations are informed by existing LCA literature on mitigation infrastructure, focused particularly on stormwater and carbon management. We specifically recommend that analysts: (1) use a performance-based functional unit; (2) be attentive to burden shifting; and (3) assess and define uncertainty, especially related to mitigation performance.

Quantifying the handprint-Footprint balance into a single score: The example of pharmaceuticals

Life Cycle Assessment typically focuses on the footprint of products and services, expressed on three Areas of Protection (AoP): Human Health, Ecosystems and Resources. While the handprint is often expressed qualitatively, quantified handprints have recently been compared directly to the footprint concerning one AoP: Human Health. We propose to take this one step further by simultaneously comparing the quantified handprint and footprint on all AoPs through normalization and weighting of the results towards a single score. We discuss two example cases of a pharmaceutical treatment: mebendazole to treat soil-transmitted helminthiases and paliperidone palmitate to treat schizophrenia. Each time, treatment is compared to 'no treatment'. The footprint of health care is compared to the handprint of improved patient health. The handprint and footprint were normalized separately. To include sensitivity in the normalization step we applied four sets of external normalization factors for both handprint (Global Burden of Disease) and footprint (ReCiPe and PROSUITE). At the weighting step we applied 26 sets of panel weighting factors from three sources. We propose the Relative Sustainability Benefit Rate (RSBR) as a new metric to quantify the relative difference in combined handprint and footprint single score between two alternatives. When only considering the footprint, the first case study is associated with an increased single score burden of treatment compared to 'no treatment', while in the second case study treatment reduces the single score burden by 41.1% compared to 'no treatment'. Also including the handprint provided new insights for the first case study, now showing a decrease of 56.4% in single score burden for treatment compared to 'no treatment'. For the second case study the reduction of single score burden was confirmed as the handprint burden was also decreased because of treatment by 9.9%, reinforcing the findings.

How to Conduct Prospective Life Cycle Assessment for Emerging Technologies? A Systematic Review and Methodological Guidance

Emerging technologies are expected to contribute to environmental sustainable development. However, throughout the development of novel technologies, it is unknown whether emerging technologies can lead to reduced environmental impacts compared to a potentially displaced mature technology. Additionally, process steps suspected to be environmental hotspots can be improved by process engineers early in the development of the emerging technology. In order to determine the environmental impacts of emerging technologies at an early stage of development, prospective life cycle assessment (LCA) should be performed. However, consistency in prospective LCA methodology is lacking. Therefore, this article develops a framework for a prospective LCA in order to overcome the methodological inconsistencies regarding prospective LCAs. The methodological framework was developed using literature on prospective LCAs of emerging technologies, and therefore, a literature review on prospective LCAs was conducted. We found 44 case studies, four review papers, and 17 papers on methodological guidance. Three main challenges for conducting prospective LCAs are identified: Comparability, data, and uncertainty challenges. The issues in defining the aim, functionality, and system boundaries of the prospective LCAs, as well as problems with specifying LCIA methodologies, comprise the comparability challenge. Data availability, quality, and scaling are issues within the data challenge. Finally, uncertainty exists as an overarching challenge when applying a prospective LCA. These three challenges are especially crucial for the prospective assessment of emerging technologies. However, this review also shows that within the methodological papers and case studies, several approaches exist to tackle these challenges. These approaches were systematically summarized within a framework to give guidance on how to overcome the issues when conducting prospective LCAs of emerging technologies. Accordingly, this framework is useful for LCA practitioners who are analyzing early-stage technologies. Nevertheless, further research is needed to develop appropriate scale-up schemes and to include uncertainty analyses for a more in-depth interpretation of results.

Effects of Spatial Scale on Life Cycle Inventory Results

Efforts to compile life cycle inventory (LCI) data at more geographically refined scales or resolutions are growing. However, it remains poorly understood as to how the choice of spatial scale may affect LCI results. Here, we examine this question using U.S. corn as a case study. We compile corn production data at two spatial scales, state and county, and compare how their LCI results may differ for state and national level analyses. For greenhouse gas (GHG) emissions, estimates at the two scales are similar (<20% of difference) for most state-level analyses and are basically the same (<5%) for national level analysis. For blue water consumption, estimates at the two scales differ more. Our results suggest that state-level analyses may be an adequate spatial scale for national level GHG analysis and for most state-level GHG analyses of U.S. corn, but may fall short for water consumption, because of its large spatial variability. On the other hand, although county-based LCIs may be considered more accurate, they require substantially more effort to compile. Overall, our study suggests that the goal of a study, data requirements, and spatial variability are important factors to consider when deciding the appropriate spatial scale or pursuing more refined scales.

A Framework for Modelling Consumption-Based Energy Demand and Emission Pathways

Energy demand in global climate scenarios is typically derived for sectors - such as buildings, transportation, and industry - rather than from underlying services that could drive energy use in all sectors. This limits the potential to model household consumption and lifestyles as mitigation options through their impact on economy-wide energy demand. We present a framework to estimate the economy-wide energy requirements and carbon emissions associated with future household consumption, by linking Industrial Ecology tools and Integrated Assessment Models (IAM). We apply the framework to assess final energy and emission pathways for meeting three essential and energy-intensive dimensions of basic well-being in India: food, housing and mobility. We show, for example, that nutrition-enhancing dietary changes can reduce emissions by a similar amount as meeting future basic mobility in Indian cities with public transportation. The relative impact of energy demand reduction measures compared to decarbonization differs across these services, with housing having the lowest and food the highest. This framework provides complementary insights to those obtained from IAM by considering a broader set of consumption and well-being-related interventions, and illustrating trade-offs between demand and supply-side options in climate stabilization scenarios.

Improving Policy Evidence Base for Agricultural Sustainability and Food Security: A Content Analysis of Life Cycle Assessment Research

Life cycle assessment is a widespread method for measuring and monitoring the environmental impacts of production processes, thereby allowing the comparison of business-as-usual with more ecological scenarios. Life cycle assessment research can support evidence-based policy making by comparing and communicating the environmental impacts of agricultural and food systems, informing about the impact of mitigating interventions and monitoring sectoral progress towards sustainable development goals. This article aims at improving the contribution of science to evidence-based policies for agricultural sustainability and food security, while facilitating further research, by delivering a content-analysis based literature review of life cycle assessment research in agricultural and food economics. Results highlight that demand-side and system-level approaches need further development, as policies need to support redesigned agricultural systems and newly conceived dietary guidelines, which combine environmental protection and health benefits, without reducing productivity. Similarly, more research effort towards consequential life cycle assessment and multidimensional assessment may benefit policy makers by considering the rebound effects associated with the large-scale implementation of impact-mitigating interventions. Promising interventions involve the promotion of waste circularization strategies, which could also improve the profitability of agriculture. For effective policy making towards agricultural sustainability and food security worldwide, countries with the greatest expected population growth and raise of urbanization rates need more attention by researchers.

Substitution modelling in life cycle assessment of municipal solid waste management

Life cycle assessment (LCA) is gaining importance worldwide in guiding waste management policies. The capacity of co-products such as recycled materials and recovered energy to avoid primary production of equivalent products largely determines the environmental performance of waste treatment technologies. Estimating the reductions in resource use, emissions, and impacts enabled by this substitution of primary production is often the most influential and controversial factor in quantifying the overall environmental performance of a waste management strategy. This study aims to critically evaluate the modelling of substitution in LCAs of recovered material from municipal solid waste management systems (MSWMS) by answering two questions. First, to what extent is substitution modelling transparently documented in the literature? Second, are the substitution ratios justified to represent physically realistic replacement of one product by another? To address these questions, we performed a systematic analysis of 51 LCA studies on MSWMS published in the peer-reviewed literature. We found that 22% of the substitution ratios are only implicitly expressed. A significant proportion of substitution ratios is not justified (65%), while for the remaining 35%, justifications do not represent physically realistic substitutions. We call for more rigor and transparency, and we propose guidance for the documentation of substitution ratios, with the aim of reaching more credible and robust analyses. For the justification of a substitution ratio to be considered physically realistic, information should notably be provided concerning loss of quality, the function performed by substitutable materials, and the sector of use.

An Integrated Approach to Determining the Capacity of Ecosystems to Supply Ecosystem Services into Life Cycle Assessment for a Carbon Capture System

In the life cycle assessment (LCA) method, it is not possible to carry out an integrated sustainability analysis because the quantification of the biophysical capacity of the ecosystems to supply ecosystem services is not taken into account. This paper considers a methodological proposal connecting the flow demand of a process or system product from the technosphere and the feasibility of the ecosystem to supply based on the sink capacity. The ecosystem metabolism as an analytical framework and data from a case study of an LCA of combined heat and power (CHP) plant with and without post-combustion carbon capture (PCC) technology in Mexico were applied. Three scenarios, including water and energy depletion and climate change impact, are presented to show the types of results obtained when the process effect of operation is scaled to one year. The impact of the water–energy–carbon nexus over the natural infrastructure or ecological fund in LCA is analyzed. Further, the feasibility of the biomass energy with carbon capture and storage (BECCS) from this result for Mexico is discussed. On the supply side, in the three different scenarios, the CHP plant requires between 323.4 and 516 ha to supply the required oil as stock flow and 46–134 ha to supply the required freshwater. On the sink side, 52–5,096,511 ha is necessary to sequester the total CO2 emissions. Overall, the CHP plant generates 1.9–28.8 MW/ha of electricity to fulfill its function. The CHP with PCC is the option with fewer ecosystem services required.

Bridging the Data Gap in the Water Scarcity Footprint by Using Crop-Specific AWARE Factors

The assessment of the water scarcity footprint of products emerged as an important step in supporting water management strategies. Among others, the AWARE methodology was published as a consensus-based indicator to perform such an assessment at a watershed level and monthly scale. The need to adopt such a detailed resolution, however, collides with the availability of data, so that general year and country-wide factors are commonly used. The objective of this study is to develop and verify the applicability of 26 crop-specific water scarcity characterization factors to help assess the water scarcity footprint when data and information availability is limited. To do so, a weighted average consumption approach was adopted, starting from local AWARE characterization factors and local crop-specific water consumption. The resulting factors, ranging from 0.19 m3/ton eq for “other perennial crop” in Brunei to 9997 m3/ton eq for “other annual crop” in Mauritania, illustrate the large variability of potential water scarcity impacts. Factors were applied to the water consumption of selected crops to assess their water scarcity footprint. The results of the study confirmed that the use of crop-specific factors is recommended as they are a better proxy of water scarcity in a region when compared to their national generic counterparts.

Projection of National Carbon Footprint in Japan with Integration of LCA and IAMs

In order to achieve target greenhouse gas (GHG) emissions, such as those proposed by each country by nationally determined contributions (NDCs), GHG emission projections are receiving attention around the world. Generally, integrated assessment models (IAMs) are used to estimate future GHG emissions considering both economic structure and final energy consumption. However, these models usually do not consider the entire supply chain, because of differences in the aims of application. In contrast, life cycle assessment (LCA) considers the entire supply chain but does not cover future environmental impacts. Therefore, this study aims to evaluate the national carbon footprint projection in Japan based on life cycle thinking and IAMs, using the advantages of each. A future input–output table was developed using the Asia-Pacific integrated model (AIM)/computable general equilibrium (CGE) model (Japan) developed by the National Institute for Environmental Studies (NIES). In this study, we collected the fundamental data using LCA databases and estimated future GHG emissions based on production-based and consumption-based approaches considering supply chains among industrial sectors. We targeted fiscal year (FY) 2030 because the Japanese government set a goal for GHG emissions in 2030 in its NDC report. Accordingly, we set three scenarios: FY2005 (business as usual (BAU)), FY2030 (BAU), and FY2030 (NDC). As a result, the carbon footprint (CFP) in FY2030 will be approximately 1097 megatons of carbon dioxide equivalent (MtCO₂eq), which is 28.5% lower than in FY2005. The main driver of this reduction is a shift in energy use, such as the introduction of renewable energy. According to the results, the CFP from the consumption side, fuel combustion in the use stage, transport and postal services, and electricity influence the total CFP, while results of the production side showed the CFP of the energy and material sectors, such as iron and steel and transport, will have an impact on the total CFP. Moreover, carbon productivity will gradually increase and FY2030 (NDC) carbon productivity will be higher than the other two cases.

Human Health and Ecosystem Impacts of Deep Decarbonization of the Energy System

Global warming mitigation strategies are likely to affect human health and biodiversity through diverse cause-effect mechanisms. To analyze these effects, we implement a methodology to link TIMES energy models with life cycle assessment using open-source software. The proposed method uses a cutoff to identify the most relevant processes. These processes have their efficiencies, fuel mixes, and emission factors updated to be consistent with the TIMES model. The use of a cutoff criterion reduces exponentially the number of connection points between models, facilitating the analysis of scenarios with a large number of technologies involved. The method is used to assess the potential effects of deploying low-carbon technologies to reduce combustion emissions in the province of Quebec (Canada). In the case of Quebec, the reduction of combustion emissions is largely achieved through electrification of energy services. Global warming mitigation efforts reduce the impact on human health and ecosystem quality, mainly because of lower global warming, water scarcity, and metal contamination impacts. The TIMES model alone underestimated the reduction of CO_2eq by 21% with respect to a full account of emissions.

Proposed Green Development Reporting Framework for Enterprises from a Life-Cycle Perspective and a Case Study in China

Green development is becoming prioritized in industrial settings and manufacturing. Under the current trend of green development, the status of the green development of enterprises is not clear. Evaluation indicators of green development are required, especially given that China has issued many green development policies, as well as special funding support. Reporting is an important tool to foster communication among governments, the public, enterprises, and stakeholders, as well as to assess advances in, and provide guidance, toward realizing green development. The purpose of the present study was to establish a green development report framework and green development indicators for enterprises, with an application to a case study of a textile company in China. The green development reporting framework was based on a life-cycle assessment method, which is an index system constructed to combine quantitative and qualitative indicators, process control and outcome-oriented indicators within the scope of both life-cycle and factory boundaries. This index system included definitions and calculations methods of environmental and resource indicators that can comprehensively reflect green development. By using empirical data from 2017 in the case study, the framework and indicators were further described, and the effects of relevant terms were noted. The green development reporting framework and case study herein can help enterprises understand the concept of green development, self-inspection, self-comparison, communicate advancements, and ultimately improve their level of green development.

Knowledge Mapping of Carbon Footprint Research in a LCA Perspective: A Visual Analysis Using CiteSpace

Carbon emissions are inevitably linked to lifestyle and consumption behaviours, and the concept of “carbon footprinting” is now well-recognised beyond academia. Life cycle assessment (LCA) is one of the primary tools for assessing carbon footprints. The aim of this paper is to present a systematic review of literatures focusing on carbon footprint calculated with life cycle assessment. We used CiteSpace software to draw the knowledge map of related research to identify and trace the knowledge base and frontier terminology. It was found that the LCA application in respects of carbon footprint studies was completed mainly for the following aspect: beef production and dairy industry, seafood and fishery, nutrition, urban structure and energy use. The CiteSpace analysis showed the development path of the above aspects, for example, beef production and dairy industry has been a long-term topic in this kind of research, while the topic of nutrition appeared in recent years. There was also a cluster of literature discussing footprint evaluation tools, such as comparing LCA with input–output analysis. The CiteSpace analysis indicated that earlier methodological literature still plays an important role in recent research. Moreover, through the analysis of burst keywords, it was found that agriculture productions (dairy, meat, fish, crop) as well as global climate issues (greenhouse gases emission, global warming potential) have always been the areas of concern, which matches the result of co-citation analysis. Building materials (low-carbon building, natural buildings, sustainable buildings) and soil issues (soil carbon sequestration, soil organic carbon) are the topics of recent concern, which could arouse the attention of follower-up researchers.

Enhancing waste management strategies in Latin America under a holistic environmental assessment perspective: A review for policy support

Waste remains a serious environmental and human health hazard in developing nations, including those in Latin America and the Caribbean (LA&C). Despite important breakthroughs in waste management in LA&C, the region still faces many challenges that require special attention, such as the existence of uncontrolled open dumpsters (33%) or the low recovery rates of waste fractions (below 4%). Moreover, the adoption of sophisticated waste management technologies, such as incineration or anaerobic digestion, is still lagging. This review paper provides environmentally-sound and relevant policy support for municipal solid waste management stakeholders through a critical review of the current situation of the waste management sector in LA&C from an environmental perspective. Thereafter, Life Cycle Assessment (LCA) bibliography linked to waste management, namely collection, sorting, recycling and landfilling applications and technologies worldwide, is used in order to understand potential alternative waste management strategies in LA&C, as well as the potential environmental benefits that could be attained. Finally, based on the holistic review and analysis, the adoption of more sophisticated technologies in landfill sites (e.g. landfill gas flaring), waste-to-energy, as well as higher recycling rates, would enhance waste management in the region and mitigate environmental impacts. A holistic view to support policy formulations, including climate action, for the adoption of integrated waste management strategies in LA&C is imperative.

Development of a pragmatic framework to help food and drink manufacturers select the most sustainable food waste valorisation strategy

Food waste is a significant contemporary issue in the UK, with substantial environmental, social and economic costs to the nation. Whilst efforts to reduce food waste are laudable, a significant proportion of food and drink manufacturer waste is unavoidable. On the one hand, there is a drive from industry to reclaim as much value from this waste as possible, for example, by conversion to valuable products in what is known as "valorisation". At the same time, growing social and legislative pressures mean that any attempts to valorise food waste must be performed in a sustainable manner. However, for every company and its specific food wastes, there will be multiple valorisation possibilities and few tools exist that allow food and drink manufacturers to identify which is most profitable and sustainable for them. Such a decision would need to not only consider environmental, social and economic performance, but also how ready the technology is and how well it aligns with that company's strategy. In response, this paper develops and presents a hybrid framework that guides a company in modelling the volumes/seasonality of its wastes, identifying potential valorisation options and selecting appropriate indicators for environmental, social and economic performance as well as technological maturity and alignment with company goals. The framework guides users in analyzing economic and environmental performance using Cost-Benefit Analysis and Life Cycle Assessment respectively. The results can then be ranked alongside those for social performance, technological maturity and alignment with company goals using a weighted sum model variant of Multi-Criteria Decision Analysis to facilitate easy visual comparison. This framework is demonstrated in the form of a case study with a major UK fruit consolidator to identify the optimal strategy for managing their citrus waste. Possibilities identified included sale of imperfect but still edible waste via wholesale at a significantly reduced profit and the investment in facilities to extract higher value pectin from the same waste stream using a microwave assisted pectin extraction process. Results suggest that continued sale of waste to wholesale markets is currently the most beneficial in terms of economic viability and environmental performance, but that in the medium to long term, the projected growth in the market for pectin suggests this could become the most viable strategy.

The Future of Ex-Ante LCA? Lessons Learned and Practical Recommendations

Every decision-oriented life cycle assessment (LCAs) entails, at least to some extent, a future-oriented feature. However, apart from the ex-ante LCAs, the majority of LCA studies are retrospective in nature and do not explicitly account for possible future effects. In this review a generic theoretical framework is proposed as a guideline for ex-ante LCA. This framework includes the entire technology life cycle, from the early design phase up to continuous improvements of mature technologies, including their market penetration. The compatibility with commonly applied system models yields an additional aspect of the framework. Practical methods and procedures are categorised, based on how they incorporate future-oriented features in LCA. The results indicate that most of the ex-ante LCAs focus on emerging technologies that have already gone through some research cycles within narrowly defined system boundaries. There is a lack of attention given to technologies that are at a very early development stage, when all options are still open and can be explored at a low cost. It is also acknowledged that technological learning impacts the financial and environmental performance of mature production systems. Once technologies are entering the market, shifts in market composition can lead to substantial changes in environmental performance.

An Approach for Describing the Effects of Grazing on Soil Quality in Life-Cycle Assessment

Describing the impact of farming on soil quality is challenging, because the model should consider changes in the physical, chemical, and biological status of soils. Physical damage to soils through heavy traffic was already analyzed in several life-cycle assessment studies. However, impacts on soil structure from grazing animals were largely ignored, and physically based model approaches to describe these impacts are very rare. In this study, we developed a new modeling approach that is closely related to the stress propagation method generally applied for analyzing compaction caused by off-road vehicles. We tested our new approach for plausibility using a comprehensive multi-year dataset containing detailed information on pasture management of several hundred Swiss dairy farms. Preliminary results showed that the new approach provides plausible outcomes for the two physical soil indicators “macropore volume” and “aggregate stability”.

Environmental impacts of resource recovery from wastewater treatment plants

Conventional wastewater treatment plants (WWTPs) clean wastewater and minimize water pollution; but, while doing so, they also contribute to air pollution and need energy/material input with associated emissions. However, energy recovery (e.g. anaerobic digestion) and resource recovery (e.g. water reuse) allow us to offset the adverse environmental impacts of wastewater treatment. Life cycle assessments (LCA) have been used more and more to evaluate the environmental impacts of WWTPs and to suggest improvement options. There is a need to search for resource recovery applications that genuinely realize a net-zero impact on the total environment of WWTPs. In this work, a scheme with highly efficient energy and resource recovery (especially for thermal energy) is proposed and evaluated. The environmental impact of a conventional WWTP in comparison with the scheme proposed here, with energy/resource recovery included, was calculated, and discussed with reference to LCA methodology. In the process of using LCA, it was necessary to choose a regional situation to focus on. In this case, a Chinese situation was focused as a reference, but the qualitative information gained is of worldwide relevance. The results clearly revealed that conventional WWTP does not benefit the total environment as a whole while the new scheme benefited the total environment via resource/energy recovery-based processes. Among others, thermal energy recovery played a significant role towards a net-zero LCA analysis (contributing around 40%) which suggests that more attention and research should be focused on it.

Bio-Based Production Systems: Why Environmental Assessment Needs to Include Supporting Systems

The transition to a bio-based economy is expected to deliver substantial environmental and economic benefits. However, bio-based production systems still come with significant environmental challenges, and there is a need for assessment methods that are adapted for the specific characteristics of these systems. In this review, we investigated how the environmental aspects of bio-based production systems differ from those of non-renewable systems, what requirements these differences impose when assessing their sustainability, and to what extent mainstream assessment methods fulfil these requirements. One unique characteristic of bio-based production is the need to maintain the regenerative capacity of the system. The necessary conditions for maintaining regenerative capacity are often provided through direct or indirect interactions between the production system and surrounding “supporting” systems. Thus, in the environmental assessment, impact categories affected in both the primary production system and the supporting systems need to be included, and impact models tailored to the specific context of the study should be used. Development in this direction requires efforts to broaden the system boundaries of conventional environmental assessments, to increase the level of spatial and temporal differentiation, and to improve our understanding of how local uniqueness and temporal dynamics affect the performance of the investigated system.

Life cycle assessment (LCA) of food waste treatment in Hong Kong: On-site fermentation methodology

"Smart Food Waste Recycling Bin" (S-FRB) systems have recently been developed to facilitate the transformation of food waste into an end-product suitable for use as an energy resource following circular economy principles. This decentralized waste decomposition system utilizes fermentative microorganisms for the treatment of organic food waste and has emerged as a possible solution for coping with both landfill capacity and greenhouse gas emissions issues. This paper utilizes Life Cycle Assessment (LCA) to determine the environmental impacts associated with this S-FRB technology and identify environmental hotspots to reduce these impacts. In this paper, we have conducted an on-site pilot-scale study for 2 months at a canteen located at the City University of Hong Kong, which resulted in a 90% reduction in the mass of food waste treated in the S-FRB system. Based on this pilot-scale study hypothetical scenarios were developed to determine potential environmental impacts potential scaled-up deployments of the S-FRB instrument based on varied assumptions. Examination of the LCAs of these different scenarios demonstrated the potential for further reduction in CO₂ equivalent emissions during food waste treatment. Cumulative Energy Demand (CED) and Energy Return on Investment (EROI) were also investigated to understand the energy balance energy of the S-FRB technology. Finally, using current waste treatment methods in Hong Kong as a benchmark, the environmental impacts of the S-FRB are compared with the conventional food waste treatment approaches such as landfilling and organic waste treatment facilities (OWTF).

The Third Wave of LCA as the “Decade of Consolidation”

Several authors have pointed out the importance of systems thinking, and have considered both environmental and social aspects (holistic perspective) of sustainability assessment in the past. Sustainability assessment tools which integrate different aspects (e.g., environmental/social aspects) in order to identify negative impacts have already been developed. Common tools used to assess environmental, social, or economic impacts include the life cycle assessment (LCA), social life cycle assessment (S-LCA), life cycle costing (LCC) and life cycle sustainability assessment (LCSA) approaches. The goal of the present study was to investigate how and to what extent the three dimensions of sustainability (environmental, social, economic; holistic sustainability perspective) have been integrated into the field of LCA. A topic modeling method was applied to examine whether the emphasis placed on integrating environmental, social, and economic aspects in sustainability assessment has resulted in a more comprehensive application of the LCA approach. The results show that topics related to energy and infrastructure are currently prevailing, and that topics related to methods have been decreasing since 1997. A minor discussion of social aspects and a lack of discussion on economic aspects were identified in the present study. These results do not support the predicted “decade of life cycle sustainability assessment.” Consequently, a new period of LCA extension and application is predicted, namely, the third wave of LCA as the “decade of consolidation.” During this period, the LCA framework will be enhanced to reduce existing practical and methodological difficulties and integrate environmental and social aspects in a sustainability assessment to support global sustainable development.

Climate change mitigation potential of carbon capture and utilization in the chemical industry

Chemical production is set to become the single largest driver of global oil consumption by 2030. To reduce oil consumption and resulting greenhouse gas (GHG) emissions, carbon dioxide can be captured from stacks or air and utilized as alternative carbon source for chemicals. Here, we show that carbon capture and utilization (CCU) has the technical potential to decouple chemical production from fossil resources, reducing annual GHG emissions by up to 3.5 Gt CO2-eq in 2030. Exploiting this potential, however, requires more than 18.1 PWh of low-carbon electricity, corresponding to 55% of the projected global electricity production in 2030. Most large-scale CCU technologies are found to be less efficient in reducing GHG emissions per unit low-carbon electricity when benchmarked to power-to-X efficiencies reported for other large-scale applications including electro-mobility (e-mobility) and heat pumps. Once and where these other demands are satisfied, CCU in the chemical industry could efficiently contribute to climate change mitigation.

Time Value of Greenhouse Gas Emissions in Life Cycle Assessment and Techno-Economic Analysis

Life cycle assessment is a fundamental tool used to evaluate the environmental impact of products. Standard life cycle assessment methodology ignores the impact of greenhouse gases relative to when they are emitted. In this paper, we present a method for leveraging the social cost of greenhouse gases to account for the temporal impacts of emissions in life cycle assessment and techno-economics. To demonstrate, we use this method to analyze the present value of the monetized impacts of emissions across multiple electricity generation technologies. Results show that accounting for time increases the present value across all but one of the technologies considered. Carbon intensive technologies show the highest increase, with coal rising between 26% and 62% depending on social cost scenario. Additionally, we demonstrate a second method that combines temporally resolved greenhouse gas emissions with techno-economic analysis. Considering temporal impacts of emissions within techno-economic analysis increases the levelized cost of electricity (LCOE) across all technologies considered. Carbon intensive technologies increase significantly, with the LCOE from coal rising between 37% and 263% depending on the social cost scenario. The proposed methods show that temporal resolution in life cycle assessment is critical for comparing the monetized impacts of greenhouse gas emissions across technologies.

Integrating Protein Quality and Quantity with Environmental Impacts in Life Cycle Assessment

Life cycle assessment (LCA) evaluates environmental impacts of a product from material extraction through disposal. Applications of LCA in evaluating diets and foods indicate that plant-based foods have lower environmental impacts than animal-based foods, whether on the basis of total weight or weight of the protein content. However, LCA comparisons do not differentiate the true biological value of protein bioavailability. This paper presents a methodology to incorporate protein quality and quantity using the digestible indispensable amino acid score (DIAAS) when making comparisons using LCA data. The methodology also incorporates the Food and Drug Administration’s (FDA) reference amounts customarily consumed (RACCs) to best represent actual consumption patterns. Integration of these measures into LCA provides a mechanism to identify foods that offer balance between the true value of their protein and environmental impacts. To demonstrate, this approach is applied to LCA data regarding common protein foods’ global warming potential (GWP). The end result is a ratio-based score representing the biological value of protein on a GWP basis. Principal findings show that protein powders provide the best efficiency while cheeses, grains, and beef are the least efficient. This study demonstrates a new way to evaluate foods in terms of nutrition and sustainability.

Advances in Sustainable Catalysis: A Computational Perspective

The enormous challenge of moving our societies to a more sustainable future offers several exciting opportunities for computational chemists. The first principles approach to "catalysis by design" will enable new and much greener chemical routes to produce vital fuels and fine chemicals. This prospective outlines a wide variety of case studies to underscore how the use of theoretical techniques, from QM/MM to unrestricted DFT and periodic boundary conditions, can be applied to biocatalysis and to both homogeneous and heterogenous catalysts of all sizes and morphologies to provide invaluable insights into the reaction mechanisms they catalyze.