Attributional & Consequential Life Cycle Assessment: Definitions, Conceptual Characteristics and Modelling Restrictions

Identifying the opportunities for sustainable bitumen production in India

The present study assessed the environmental impacts due to bitumen production in India using life cycle assessment approach. The impacts were calculated for production of 1 t of bitumen and system boundary covered extraction of resources, processing at refinery, transportation of bitumen and storage at the production site. In this study, five scenarios were considered to estimate the impacts reduction assuming different future electricity mix and thermal energy source. Crude oil extraction phase had contributed highest (91%) followed by refinery phase (4%), then transportation (3%) and at last storage of bitumen (2%). The normalization results found that the bitumen production had highest impacts on abiotic depletion fossil and lowest impact on eutrophication. Scenario S4 had the least environmental impacts and provided the overall reductions of 33% compared to the baseline scenario. Scenario S4 reduced the impacts significantly on acidification (51%), eutrophication (30%), and human toxicity (71%), but the reductions were not significant on global warming (11%) and increased the impacts on abiotic depletion fossil (1%). The results of sensitivity analysis found that thermal energy obtained from hard coal consumed during bitumen production is the most sensitive parameter for all the impact categories. The uncertainty analysis showed that the results of this study are reliable and had standard deviation less than 5% for all the impact categories. The findings of the present study will help the decision makers and concerned authorities to reduce the environmental impacts from bitumen production in India.

Life cycle assessment and industrial synergy for carbon reduction: A circular economy approach

In the face of the climate change crisis, circular economy (CE) is put forward as a promising key to the sustainable development goals (SDGs) riddle. In this context that affects developed and developing countries alike, circular initiatives arise, such is the case for Morocco where an industrial synergy based on the CE concept of 'waste is food' can be envisioned between the local phosphate and cement industries. In order to support and guide this initiative, a life cycle assessment (LCA) was conducted to compare the environmental performance of the production of ordinary Portland cement (OPC), limestone calcined clay cement (LC3) and a phosphate waste-based cement known as calcined marl cement (CMC). In addition to a mass-based functional unit (FU), a performance-based FU was adopted to account for the 'longer service lives' concept of CE, which necessitated the estimation of cements' service lives and CO2 uptake potentials. Results show that CMC and LC3 production respectively reduce impacts on global warming by 23 % and 60 %, while the country aims for a 18.3 % reduction by 2030; mineral resource scarcity is reduced by 30 % and 48 %; and other impacts by 10 % and 40 % compared with OPC. This is chiefly due to CMC and LC3's better durability performance and lower clinker content. Using LCA results, carbon tax was pre-estimated to drop by 9 and 18$/ton of cement for CMC and LC3. A life cycle costing and a social LCA must be conducted to comprehensively guide stakeholders in their decision-making process regarding a phosphate-cement synergy.

Residual biomasses at scale: Ensuring future bioeconomy uses outperform current baseline

To shift towards low-fossil carbon economies, making more out of residual biomass is increasingly promoted. Yet, it remains unclear if implementing advanced technologies to reuse these streams really achieves net environmental benefits compared to current management practices. By integrating spatially-explicit resource flow analysis, consequential life cycle assessment (LCA), and uncertainty analysis, we propose a single framework to quantify the residual biomass environmental baseline of a territory, and apply it to the case of France. The output is the environmental threshold that a future large-scale territorial bioeconomy strategy should overpass. For France, we estimate the residual biomass baseline to generate 18.4 ± 2.7 MtCO2-eq·y-1 (climate change), 255 ± 35 ktN-eq·y-1 (marine eutrophication), and 12,300 ± 800 disease incidences per year (particulate matter formation). The current use of crop residues and livestock effluents, being essentially a return to arable lands, was found to represent more than 90 % of total environmental impacts and uncertainties, uncovering a need for more certain data. At present, utilizing residual streams as organic fertilizers fulfills over half of France's total phosphorus (P) and potassium (K) demands. However, it only meets 6 % of the nitrogen demand, primarily because nitrogen is lost through air and water. This, coupled with the overall territorial diagnosis, led us to revisit the idea of using the current situation (based on 2018 data) as a baseline for future bioeconomy trajectories. We suggest that these should rather be compared to a projected baseline accounting for ongoing basic mitigation efforts, estimated for France at 8.5 MtCO2-eq·y-1.

Evaluation of Climate-Aware Metrics Tools for Radiology Informatics and Artificial Intelligence: Toward a Potential Radiology Ecolabel

Radiology is a major contributor to health care's impact on climate change, in part due to its reliance on energy-intensive equipment as well as its growing technological reliance. Delivering modern patient care requires a robust informatics team to move images from the imaging equipment to the workstations and the health care system. Radiology informatics is the field that manages medical imaging IT. This involves the acquisition, storage, retrieval, and use of imaging information in health care to improve access and quality, which includes PACS, cloud services, and artificial intelligence. However, the electricity consumption of computing and the life cycle of various computer components expands the carbon footprint of health care. The authors provide a general framework to understand the environmental impact of clinical radiology informatics, which includes using the international Greenhouse Gas Protocol to draft a definition of scopes of emissions pertinent to radiology informatics, as well as exploring existing tools to measure and account for these emissions. A novel standard ecolabel for radiology informatics tools, such as the Energy Star label for consumer devices or Leadership in Energy and Environmental Design certification for buildings, should be developed to promote awareness and guide radiologists and radiology informatics leaders in making environmentally conscious decisions for their clinical practice. At this critical climate juncture, the radiology community has a unique and pressing obligation to consider our shared environmental responsibility in innovating clinical technology for patient care.

Synergies and gaps between circularity assessment and Life Cycle Assessment (LCA)

This article evaluates the synergies between circularity assessment and Life Cycle Assessment (LCA) by investigating their alignments, misalignments, and challenges in addressing sustainability. The analysis emphasizes the significance of a multi-level approach, positioning these methods at various levels, including philosophy, strategy, assessment, and communication. The findings demonstrate that both LCA and circularity assessment can serve as sustainability assessment methods for circularity strategies, despite existing gaps. However, neither approach can provide a complete picture of a system's environmental performance on its own. Data availability, diverse assumptions, spotlights and shadows (highlighted and neglected elements), multiple life cycles, products, functions, strategies, and as well as temporal aspects are identified as the main challenges in addressing sustainability. This article provides recommendations based on the lessons learned from each approach, suggesting the integration of their strengths and addressing challenges to achieve a comprehensive understanding of environmental sustainability and make informed decisions for a circular and sustainable future. These recommendations include using function-based models and the principles of prospective and dynamic LCAs for the development of future circularity assessments. Additionally, circularity assessment can be used to establish LCA models, aiding in identifying hotspots during the goal and scope definition, and determining allocation and weighting factors in both Life Cycle Inventory (LCI) and Life Cycle Impact Assessment (LCIA).

Biodiversity Impact Assessment Considering Land Use Intensities and Fragmentation

Land use is a major threat to terrestrial biodiversity. Life cycle assessment is a tool that can assess such threats and thereby support environmental decision-making. Within the Global Guidance for Life Cycle Impact Assessment (GLAM) project, the Life Cycle Initiative hosted by UN Environment aims to create a life cycle impact assessment method across multiple impact categories, including land use impacts on ecosystem quality represented by regional and global species richness. A working group of the GLAM project focused on such land use impacts and developed new characterization factors to combine the strengths of two separate recent advancements in the field: the consideration of land use intensities and land fragmentation. The data sets to parametrize the underlying model are also updated from previous models. The new characterization factors cover five species groups (plants, amphibians, birds, mammals, and reptiles) and five broad land use types (cropland, pasture, plantations, managed forests, and urban land) at three intensity levels (minimal, light, and intense). They are available at the level of terrestrial ecoregions and countries. This paper documents the development of the characterization factors, provides practical guidance for their use, and critically assesses the strengths and remaining shortcomings.

Integrated life cycle assessment of biotreatment and agricultural use of domestic organic residues: Environmental benefits, trade-offs, and impacts on soil application

Extensive agricultural activities have been shown to degrade soils, promoting research into improving soil quality. One such method is to increase the amount of organic matter in the soil, and domestic organic residues (DOR) are commonly used for this purpose. The environmental impact of DOR-derived products, from production to agricultural application, remains unclear in current research. With the aim to have a more comprehensive understanding of the challenges and opportunities in DOR management and reuse, this study extended the boundaries of Life Cycle Assessment (LCA) to include the transport, treatment, and application of treated DOR on a national level while also quantifying soil carbon sequestration that has been less addressed in relevant LCA studies. This study focuses on The Netherlands, where incineration predominates, as a representative case to explore the benefits and trade-offs of moving towards more biotreatment for DOR. Two main biotreatments were considered, composting and anaerobic digestion. The results indicate that biotreatment of kitchen and yard residues generally has higher environmental impacts than incineration, including increased global warming and fine particulate matter formation. However, biotreatment of sewage sludge has lower environmental impacts than incineration. Substitution of nitrogen and phosphorus fertilisers with compost reduces mineral and fossil resource scarcity. In fossil-based energy systems like The Netherlands, replacing incineration with anaerobic digestion yields the highest benefit for fossil resource scarcity (61.93 %) due to energy recovery from biogas and the predominant use of fossil resources in the Dutch energy system. These findings indicate that replacing incineration with biotreatment of DOR may not benefit all impact categories in LCA. The environmental performance of substituted products can significantly influence the environmental benefits of increased biotreatment. Future studies or implementation of increased biotreatment should consider trade-offs and local context.

A framework for determining the life cycle GHG emissions of fossil marine fuels in countries reliant on imported energy through maritime transportation: A case study of South Korea

This research was motivated to address limitations in the current lifecycle assessment frameworks with the absence of proper guidelines for developing default lifecycle values of energies in consideration of supply chain activities and maritime transportation. Given this, it aims to evaluate the level of life cycle GHG emissions of heavy fuel oil, LNG, LPG and methanol as marine fuels produced and supplied in energy import-dependent countries, using South Korea as a case study. The analysis clearly shows that the impact of international shipping on Well-to-Tank (WtT) GHG emissions for energy carriers would be subject to several factors: propulsion system types, the quantify of energy transported, and the routes and distances of voyages. For instance, transportation emissions from LNG carriers for LNG fuel vary significantly depending on the country of import, ranging from 2.26 g CO2 eq./MJ (representing 12.2 % of Well-to-Tank (WtT) emissions for Malaysia) to 5.97 g CO2 eq./MJ (representing 33.3 % of WtT emissions for Qatar). As a preliminary study, an enhancement on the quality of the input/inventory data is imperative for obtaining a reliability of results. Nevertheless, the comparative analysis of different fuels and life stages provides valuable insights for stakeholders to develop effective policies and energy refueling plans for reducing life cycle GHG emissions from marine fuels. These findings could also enhance the current regulatory framework and provide meaningful lifecycle carbon footprints of marine fuels for energy importing countries. The study results also strongly suggest that default values of GHG emission for different countries relying on energy imports via international maritime transport should be further developed in consideration of the impact of regional differences, such as distance, from the importing country for successful arrival of LCA application on marine industry.

U.S. plastic waste exports: A state-by-state analysis pre- and post-China import ban

This study analyzes the regional implications of China's 2017 import ban on plastic waste by examining U.S. census data. A statistically significant decrease in total U.S. plastic waste exports was found, dropping from about 1.4 million tons to 0.6 million tons in the post-ban period. California remained the top exporter, throughout both pre- and post-ban periods, while South Carolina exhibited the highest per capita exports. Malaysia emerged as the largest importer of U.S. plastic waste, followed by Vietnam, Indonesia, and Thailand. The ban also led to a change in the composition of the exported plastic waste. Ethylene polymers increased from 32.6% of total exports in the pre-ban period to 46.9% in the post-ban period. Other plastics (vinyl chloride polymers, styrene polymers, and for plastics not elsewhere specified or included) decreased from 67.4% of total exports in the pre-ban period to 53.1% in the post-ban period. Moreover, we found that exporting plastic waste has significant environmental and human health impacts. For example, the Global Warming Potential (GWP) decreased from 20 million tons CO2-eq in the scenario where 100% of plastics are exported, or 25 million tons exported from the U.S. since 2002, to -11.1 million tons CO2-eq in the scenario where 100% of plastics are treated domestically. Transportation exacerbates these impacts for exported waste scenarios, increasing to 5.4 million tons CO2-eq when plastics are exported by ship while decreasing to 0.9 million tons CO2-eq for domestic treatment. Although exporting plastic waste is initially cost-effective, our study highlights that investing in domestic waste management can yield significant long-term benefits, considering the environmental and public health impacts. Therefore, it is crucial to prioritize context-specific solutions to address the challenges of the evolving global plastic waste landscape.

Consequential life cycle assessment of kraft lignin recovery with chemical recycling

The recovery of kraft lignin from black liquor allows an increasing of the pulp production of a kraft mill (marginal tonnage) and at the same time provide a valuable material that can be used as energy or chemical feedstock. However, because lignin precipitation is an energy- and material-consuming process, the environmental consequences from a life cycle perspective are under discourse. The aim of this study is to investigate, through the application of consequential life cycle assessment, the potential environmental benefits of kraft lignin recovery and its subsequent use as an energy or chemical feedstock. A newly developed chemical recovery strategy was assessed. The results revealed how the use of lignin as energy feedstock is not environmentally advantageous compared to producing energy directly from the pulp mill's recovery boiler. However, the best results were observed when lignin was used as a chemical feedstock in four applications to replace bitumen, carbon black, phenol, and bisphenol-A.

Transitioning to sustainable mobility in Lima, Peru. Are e-scooter sharing initiatives part of the problem or the solution?

Micro-mobility has increased in urban environments to reduce dependence on private vehicles. While electric micro-mobility alternatives are supposed to reduce environmental impacts, certain studies suggest that this can depend on the transport mode they substitute. In parallel, despite growing efforts, urban areas in developing and emerging economies struggle to implement sustainable mobility programs at a city-wide level. In March 2019 the first dockless e-scooter rental service appeared in the city of Lima, Peru. Although the social and environmental impacts of dockless e-scooters have been the center of multiple studies, these are mostly based in North America and Europe. Therefore, the main objective of the current study was to use Life Cycle Assessment (LCA) to address the environmental profile of e-scooter use in districts of central Lima. All stages of the life-cycle of e-scooters were modelled considering local conditions, from manufacture to end-of-life. A sensitivity analysis was conducted to account for the variability in environmental impact based on five parameters: lifespan, battery range, remaining battery charge, collection distance and collection vehicle. Results show that over two thirds of impacts are linked to manufacturing thanks to the low-carbon profile of electricity production in Peru, which lowers the burdens in the use phase, making e-scooter use competitive in the local market as compared to electric bikes or motorcycles. However, replacement trends show that net environmental gains are not always obtained. Poor maintenance and derived lifespan or battery range are important sources of variability for the impact categories assessed. Although e-scooters show potential for their implementation in developing cities with similar characteristics to Lima, we recommend that site-specific studies should be conducted to foster adaptive management strategies which take into account the means of transport being substituted by e-scooters.

Reflecting on the environmental impact of the captured carbon feedstock

Climate change mitigation potentials of carbon capture and utilization (CCU) closely depend on the energy and chemicals used to capture the chemically inert CO2. The potential environmental benefits of CCU are typically assessed using Life Cycle Assessment (LCA) methodology. Although LCA is a standardized method, modelling CO2 as a carbon feedstock instead of an emission introduces an ambiguous "multifunctionality issue". Inconsistent multifunctionality practices have been applied to deal with this methodological complexity in LCAs of CCU technologies. Using one method instead of another can lead to highly positive or negative carbon footprints for the same carbon source and CO2 capture process. A comprehensive guideline to clarify the best practices to conduct LCAs of CCU technologies was published in 2020 (and updated in March 2022) in a collaborative process involving over 40 experts. In this guideline and linked scientific articles from experts involved in its development, a so-called "substitution method" is recommended to avoid suboptimal choices of CO2 sources, improve comparability and harmonize decision-making. This article critically reviews the methodological formulation of the recommended method and suggests corrections to possible inaccuracies in a future update of the guideline. Furthermore, various illustrative examples of common CO2 feedstocks were used to illustrate the meaning of adopting such a method in practice. Economic-based benchmarking of the environmental impacts of CO2 feedstocks calculated with such a method was also broadly illustrated.

Carbon footprint calculation in one of the largest Gas Refinery Companies in the Middle East

Rapid technological advances in the natural gas industry raised access to natural gas reserves, related to increased greenhouse gas emissions, including CO2 and CH4. This study calculates greenhouse gas emissions (CO2 and CH4) according to sources (direct and indirect) in one of the largest gas Refinery Companies in the Middle East to analyze the carbon footprint for the first time. All computational frameworks for estimating carbon footprint and greenhouse gas emissions (CO2 and CH4) in different sectors were carried out after determining direct sources (combustion, processes, and fugitive) and indirect ones (import from National Grid's electricity) according to the requirement guide and organizations' report involved in the operational activities of the oil industry. The carbon footprint for this refinery, leading to the emission of CO2 and CH4, is in the range of 1507.1 Gg CO2/yr and 0.003 Gg CH4/yr. The highest CO2 emissions are related to the gas-sweetening unit from GHG direct emission sources, and the lowest CO2 emissions are related to fugitive ones. For methane gas, the highest CH4 emissions are related to fugitive emissions. In addition, the emission of CH4 from the gas sweetening unit and waste combustion equipment is estimated to be very small and close to zero. This study showed that it is necessary to carry out more studies in different regions to give a more comprehensive insight into gas emissions and their adverse health effects on human populations.

Upgrading agrifood co-products via solid fermentation yields environmental benefits under specific conditions only

Transforming residual biomass into edible ingredients is increasingly promoted to alleviate the environmental impacts of food systems. Yet, these approaches mostly rely on emerging technologies and constrained resources, and their environmental benefits remain unclear. By combining process-based consequential life cycle analysis, uncertainty assessment and biomass resource estimation, we quantified the impacts of deploying waste-to-nutrition pathways, here applied to the upgrading of agrifood co-products by solid-state fermentation (SSF). The benefits of reducing the demand for soybean meal by enhancing the protein concentration of feed through SSF do not compensate for the environmental burdens induced by the process on climate change, water depletion and land use. Besides unlocking feed markets to low-feed-quality streams, SSF outperforms energy valorization for most environmental impacts but is less competitive to mitigate climate change. Yet, SSF yields overall environmental benefits when unlocking food markets rather than supplying feed and energy services. Systematic methodological harmonization is required to assess the potential of novel ingredients, as outcomes vary according to the displaced food and feed baskets, and related land use changes.

Life cycle assessment of struvite recovery and wastewater sludge end-use: A Flemish illustration

Phosphate rock (PR) has been designated as a Critical Raw Material in the European Union (EU). This has led to increased emphasis on alternative P recovery (APR) from secondary streams like wastewater sludge (WWS). However, WWS end-use is a contentious topic, and EU member states prefer different end-use pathways (land application/incineration/valorisation in cement kilns). Previous Life Cycle Assessments (LCA) on APRs from WWS reached contrasting conclusions; while most considered WWS as waste and highlighted a net benefit relative to PR mining and beneficiation, others viewed WWS as a resource and highlighted a net burden of the treatment. We used a combined functional unit (that views WWS from a waste as well as a resource perspective) and applied it on a Flemish wastewater treatment plant (WWTP) with struvite recovery as APR technology. Firstly, a retrospective comparison was performed to measure the WWTP performance before and after struvite recovery and the analysis was complemented by uncertainty and global sensitivity analyses. The results showed struvite recovery provides marginal environmental benefits due to improved WWS dewatering and reduced polymer use. Secondly, a prospective LCA approach was performed to reflect policy changes regarding WWS end-use options in Flanders. Results indicated complete mono-incineration of WWS, ash processing to recover P and the subsequent land application appears to be less sustainable in terms of climate change, human toxicity, and terrestrial acidification relative to the status quo, i.e., co-incineration with municipal solid waste and valorisation at cement kilns. Impacts on fossil depletion, however, favour mono-incineration over the status quo.

Life Cycle Assessment and Preliminary Cost Evaluation of a Smart Packaging System

Smart food packaging (SP) is an innovative packaging system that can extend the shelf life of the product and reduce food waste. The objective of the study is the estimation of the environmental and economic sustainability of the overall life cycle of a SP including a chemical sensor able to detect modifications in the concentration of CO2, which is an indicator of food spoilage, and encapsulated oregano essential oil (OEO), capable of inhibiting the microbial growth. For this purpose, a life cycle assessment (LCA), following the ISO 14040 series and ReCiPe methodology, and an economic evaluation of SP, were performed. The environmental footprint (EF) of SP was compared to that of a conventional packaging (CP) in terms of packaging production, use and end of life (EoL) of both the packaging and the contained food product. The results demonstrated that the production of SP burdened by 67% the impact category of climate change. However, when adapting four use and EoL scenarios, namely the CP generates 30% food waste, whereas SP can generate 5% (optimistic scenario), 10% (realistic) or 20% (conservative) waste, SP proved to be environmentally superior in most impact categories.

Carbon Footprint Reduction by Transitioning to a Diet Consistent with the Danish Climate-Friendly Dietary Guidelines: A Comparison of Different Carbon Footprint Databases

Dietary transitions are important for combating many of the environmental challenges humanity is facing today and reducing the global burden of disease. Different dietary patterns are associated with substantially different carbon footprints (CFs). This study aims to estimate the potential CF reduction on a transition from the current Danish diet to a plant-rich diet consistent with the Danish food-based dietary guidelines (FBDG) and to compare results obtained from the use of two different CF databases. Dietary intake data for adults aged 18-64 years from the national dietary survey 2011-2013 were used to calculate the CF of the current diet, and this was compared with the estimated CF of the plant-rich diet modelled for the FBDG. Calculations were carried out using an attributional life cycle assessment (LCA) database (AU-DTU data) and compared to calculations using a top-down hybrid consequential LCA database (BCD data). The transition from the current diet to the plant-rich diet showed a substantial estimated CF reduction of 31% with AU-DTU data, and a greater reduction with BCD data (43%). Ruminant meat reduction was the largest contributor to this CF reduction, especially with the use of BCD data, and other animal-based foods also contribute considerably to the CF reduction, especially with AU-DTU data. These results indicate that the choice of LCA methodology and CF database is important in estimation of dietary CF and for the development of guidelines to promote dietary change.

Attributional and consequential LCAs of a novel bio-jet fuel from Dutch potato by-products

To mitigate the climate change impact of aviation, jet fuels from bio-based by-products are considered a promising alternative to conventional jet fuels. Life cycle assessment (LCA) is a commonly applied tool to determine the environmental impacts of bio-jet fuels. This article presents both attributional and consequential LCA models to assess an innovative bio-jet fuel produced from potato by-products in the Netherlands. The two models led to opposite conclusions regarding the overall environmental performance of this bio-jet fuel. The attributional LCA showed that this bio-jet fuel could offer about a 60% GHG emissions reduction compared to conventional jet fuel. In comparison, the consequential LCA estimated either a much lower climate change benefit (5-40%) if the potato by-products taken from the animal feed market are replaced with European animal feed or a 70% increase in GHG emissions if also imported soybean meals are used to replace the feed. Contrasting conclusions were also obtained for photochemical ozone formation. Conversely, the attributional and consequential LCAs agree on acidification, terrestrial eutrophication and depletion of fossil fuels. Although the consequential LCA was affected by higher uncertainties related to the determination of the actual product displaced, it allowed understanding the consequence of additional animal feed production. This process was not included in the system boundaries of the attributional LCA.