Accounting for ecosystem services in Life Cycle Assessment, Part II: toward an ecologically based LCA

Development of an LCA characterization factor to account UHI local effect on terrestrial ecosystems damage category: Evaluation of European Bombus and Onthophagus genera heat-stress mortality

Life Cycle Assessment as currently implemented fails in detecting and measuring the interactions between urban climate and built environment, specifically the urban heat island, providing potentially misleading results. The present study offers an advancement in Life Cycle Assessment methodology, and specifically in ReCiPe2016 method, by (a) suggesting the implementation of the Local Warming Potential midpoint impact category where the variation of urban temperature converges; (b) developing a new characterization factor through the definition of damage pathways to assess the effect of urban heat island on terrestrial ecosystems damage category, specifically on European Bombus and Onthophagus genera; (c) defining local endpoint damage categories where environmental local impacts can be addressed. The developed characterization factor has been applied to the case study of an urban area in Rome, Italy. The results show that the evaluation of the effects of urban overheating on local terrestrial ecosystems is meaningful and may support urban decision-makers who want to holistically assess urban plans.

Life Cycle Assessment Applied to Nature-Based Solutions: Learnings, Methodological Challenges, and Perspectives from a Critical Analysis of the Literature

The use of life cycle assessment (LCA) allows work to go beyond the traditional scope of urban nature-based solutions (NBS), in which ecosystem services are provided to citizens, to include environmental impacts generated over the entire life cycle of the NBS, i.e., from raw material extraction, through materials processing, production, distribution, and use stages, to end-of-life management. In this work, we explored how LCA has been applied in the context of NBS through a critical analysis of the literature. Systems under review were not restricted to one typology of NBS or another, but were meant to cover a broad range of NBS, from NBS on the ground, water-related NBS, building NBS, to NBS strategies. In total, 130 LCA studies of NBS were analysed according to several criteria derived from the LCA methodology or from specific challenges associated with NBS. Results show that studies were based on different scopes, resulting in the selection of different functional units and system boundaries. Accordingly, we propose an innovative approach based on the ecosystem services (ES) concept to classify and quantify these functional units. We also identify and discuss two recent and promising approaches to solve multifunctionality that could be adapted for LCA of NBS.

Towards a comprehensive sustainability methodology to assess anthropogenic impacts on ecosystems: Review of the integration of Life Cycle Assessment, Environmental Risk Assessment and Ecosystem Services Assessment

Nowadays, a variety of methodologies are available to assess local, regional and global impacts of human activities on ecosystems, which include Life Cycle Assessment (LCA), Environmental Risk Assessment (ERA) and Ecosystem Services Assessment (ESA). However, none can individually assess both the positive and negative impacts of human activities at different geographical scales in a comprehensive manner. In order to overcome the shortcomings of each methodology and develop more holistic assessments, the integration of these methodologies is essential. Several studies have attempted to integrate these methodologies either conceptually or through applied case studies. To understand why, how and to what extent these methodologies have been integrated, a total of 110 relevant publications were reviewed. The analysis of the case studies showed that the integration can occur at different positions along the cause-effect chain and from this, a classification scheme was proposed to characterize the different integration approaches. Three categories of integration are distinguished: post-analysis, integration through the combination of results, and integration through the complementation of a driving method. The literature review highlights that the most recurrent type of integration is the latter. While the integration through the complementation of a driving method is more realistic and accurate compared to the other two categories, its development is more complex and a higher data requirement could be needed. In addition to this, there is always the risk of double-counting for all the approaches. None of the integration approaches can be categorized as a full integration, but this is not necessarily needed to have a comprehensive assessment. The most essential aspect is to select the appropriate components from each methodology that can cover both the environmental and socioeconomic costs and benefits of human activities on the ecosystems.

Global Assessment of Agricultural Productivity Losses from Soil Compaction and Water Erosion

To guide us toward a sustainable future, the impacts of human activities on natural resources need to be understood and quantified. In this study on global agriculture, we use a Life Cycle Assessment framework to estimate potential long-term soil productivity losses caused by soil compaction and water erosion due to agricultural crop production. We combine several data sets to model spatially resolved Life Cycle Inventory information at the global level and multiply results with characterization factors from a previous publication. The global picture shows a compaction-stressed "Global North" and an erosion-stressed "Global South", with some countries and regions in between, for example, China and parts of South America. Results show that both compaction and water erosion impacts matter at the global level and that overall potential long-term productivity losses of 10-20% can be expected, with high relative impacts on low input production systems. These losses might limit long-term agricultural productivity and lead to additional land use change. Our work adds to and extends the discussion of global assessments of soil degradation. Furthermore, we prove the suggested framework to be applicable and useful for Life Cycle Assessments and other studies and provide results that can be used in such global assessments.

A Multifunctional Solution for Wicked Problems: Value-Chain Wide Facilitation of Legumes Cultivated at Bioregional Scales Is Necessary to Address the Climate-Biodiversity-Nutrition Nexus

Well-managed legume-based food systems are uniquely positioned to curtail the existential challenge posed by climate change through the significant contribution that legumes can make toward limiting Green House Gas (GHG) emissions. This potential is enabled by the specific functional attributes offered only by legumes, which deliver multiple co-benefits through improved ecosystem functions, including reduced farmland biodiversity loss, and better human-health and -nutrition provisioning. These three critical societal challenges are referred to collectively here as the “climate-biodiversity-nutrition nexus.” Despite the unparalleled potential of the provisions offered by legumes, this diverse crop group remains characterized as underutilized throughout Europe, and in many regions world-wide. This commentary highlights that integrated, diverse, legume-based, regenerative agricultural practices should be allied with more-concerted action on ex-farm gate factors at appropriate bioregional scales. Also, that this can be achieved whilst optimizing production, safeguarding food-security, and minimizing additional land-use requirements. To help avoid forfeiting the benefits of legume cultivation for system function, a specific and practical methodological and decision-aid framework is offered. This is based upon the identification and management of sustainable-development indicators for legume-based value chains, to help manage the key facilitative capacities and dependencies. Solving the wicked problems of the climate-biodiversity-nutrition nexus demands complex solutions and multiple benefits and this legume-focus must be allied with more-concerted policy action, including improved facilitation of the catalytic provisions provided by collaborative capacity builders—to ensure that the knowledge networks are established, that there is unhindered information flow, and that new transformative value-chain capacities and business models are established.

A new approach of ecologically based life cycle assessment for biological wastewater treatments focused on energy recovery goals

The energy potential of high-organic loaded agro-industrial effluents receiving biological treatment is often neglected, particularly in emergent regions, because of different technical and regulatory drawbacks. In addition, small alternative bioenergy sources are forced to compete disadvantageously with conventional energy supply, hindering their more extended exploitation. Thus, smart strategies to prove the environmental/economic potential of biogas and sludge produced in biological wastewater treatment systems (Bio-WWTs) are required to promote them as truly sustainable energy sources. In this view, the present study depicts a refined methodological framework for a more appropriate appraisal of Bio-WWTs promoting bioenergy recovery. Life cycle assessment (LCA) and emergy analysis (EmA) methods were merged around the statement of some identified and stated Principle-Criteria of Sustainability (PCS) for this kind of "water-energy nexus." As a result, a novel set of four single sustainability development indicators (SDIs) and one aggregated SDI were obtained to address sustainable conditions for valorization of bio-energy from agro-industrial Bio-WWTs. These indicators were made up of an environmental term coming from an LCA based on a system expansion approach as well as a second or "eco-economic" term obtained by means of EmA. This work introduces and shapes the "additionality" notion as an expression of overall sustainability and uses novel sustainability charts to interpret the obtained SDIs and their shifting or changes for different Bio-WWTs' life cycle scenarios. The "proof of concept" of this methodology is discussed along the obtained results for two case studies in Colombia.

A perspective on the role of uncertainty in sustainability science and engineering

The Trans-Atlantic Research and Development Interchange on Sustainability Workshop (TARDIS) is a meeting on scientific topics related to sustainability. The 2019 workshop theme was "On the Role of Uncertainty in Managing the Earth for Global Sustainability." This paper presents the perspectives on this topic derived from talks and discussions at the 2019 TARDIS workshop. There are four kinds of uncertainties encountered in sustainability ranging from clear enough futures to true surprises. The current state-of-the-art in assessing and mitigating these uncertainties is discussed.

Determining the net environmental performance of hydropower: A new methodological approach by combining life cycle and ecosystem services assessment

In the face of climate-ecological breakdown, it is well known that the world aims at developing renewable energies in order to replace fossil fuels. However, there is a great concern regarding their environmental-ecological issues specially with those ones that have a deep interplay with its immediate environment such the case of hydropower. Despite efforts, the existing environmental-ecological methodologies and approaches are incapable to encompass the wide impacts of hydropower. To bridge this knowledge gap, the goal of this paper is twofold: first, to propose a methodological approach that combines and balances two well-known environmental-ecological assessments: life cycle (LCA) and ecosystem services assessment (ESA). This way, the proposal enables a deeper look into the environmental-ecological performance. Second, to determine the total environmental-ecological accounting and hence the net environmental performance of hydropower. In order to expose the applicability of the proposed methodological approach, case studies of a dam and run-of-river hydropower plant located in Ecuador were examined. Analysis found a net environmental performance (NEP) of -0.98 $/kWh and -0.08 $/kWh, respectively. These results clearly indicate a marked environmental-ecological difference between these two hydropower schemes, awareness of which may be helpful for further decision-making and developing new energy policies in pursuit of sustainable development goals. What is more, this methodological approach may be applied and extended not only to other renewable energy technologies, but also to any other project or activity where the exploitation and use of natural resources are involved.

An improved life cycle impact assessment principle for assessing the impact of land use on ecosystem services

In order to consider the effects of land use, and the land cover changes it causes, on ecosystem services in life cycle assessment (LCA), a new methodology is proposed and applied to calculate midpoint and endpoint characterization factors. To do this, a cause-effect chain was established in line with conceptual models of ecosystem services to describe the impacts of land use and related land cover changes. A high-resolution, spatially explicit and temporally dynamic modeling framework that integrates land use and ecosystem services models was developed and used as an impact characterization model to simulate that cause-effect chain. Characterization factors (CFs) were calculated and regionalized at the scales of Luxembourg and its municipalities, taken as a case to show the advantages of the modeling approach. More specifically, the calculated CFs enable the impact assessment of six land cover types on six ecosystem functions and two final ecosystem services. A mapping and comparison exercise of these CFs allowed us to identify spatial trade-offs and synergies between ecosystem services due to possible land cover changes. Ultimately, the proposed methodology can offer a solution to overcome a number of methodological limitations that still exist in the characterization of impacts on ecosystem services in LCA, implying a rethinking of the modeling of land use in life cycle inventory.

Towards integrating the ecosystem services cascade framework within the Life Cycle Assessment (LCA) cause-effect methodology

The assessment of ecosystem services (ES) is covered in a fragmented manner by environmental decision support tools that provide information about the potential environmental impacts of supply chains and their products, such as the well-known Life Cycle Assessment (LCA) methodology. Within the flagship project of the Life Cycle Initiative (hosted by UN Environment), aiming at global guidance for life cycle impact assessment (LCIA) indicators, a dedicated subtask force was constituted to consolidate the evaluation of ES in LCA. As one of the outcomes of this subtask force, this paper describes the progress towards consensus building in the LCA domain concerning the assessment of anthropogenic impacts on ecosystems and their associated services for human well-being. To this end, the traditional LCIA structure, which represents the cause-effect chain from stressor to impacts and damages, is re-casted and expanded using the lens of the ES 'cascade model'. This links changes in ecosystem structure and function to changes in human well-being, while LCIA links the effect of changes on ecosystems due to human impacts (e.g. land use change, eutrophication, freshwater depletion) to the increase or decrease in the quality and/or quantity of supplied ES. The proposed cascade modelling framework complements traditional LCIA with information about the externalities associated with the supply and demand of ES, for which the overall cost-benefit result might be either negative (i.e. detrimental impact on the ES provision) or positive (i.e. increase of ES provision). In so doing, the framework introduces into traditional LCIA the notion of "benefit" (in the form of ES supply flows and ecosystems' capacity to generate services) which balances the quantified environmental intervention flows and related impacts (in the form of ES demands) that are typically considered in LCA. Recommendations are eventually provided to further address current gaps in the analysis of ES within the LCA methodology.

China's natural resources balance sheet from the perspective of government oversight: Based on the analysis of governance and accounting attributes

One of the top priorities of the Chinese government's oversight is to address the conflicts between economic growth and resource consumption and between economic development and ecological damage. In this regard, the advocacy and compilation of the natural resources balance sheet can boost the efficiency of the government's oversight and improve the quality of resource management. However, China's natural resources balance sheet is still at an exploratory stage, lacking the theoretical framework of balance sheet preparation, preparatory ideas, and a reporting system, which must be established urgently. First, the study states the purpose of compiling the natural resources balance sheet, and, subsequently, analyzes the theoretical basis, framework system, preparatory ideas, and sample sheet format, thereby offering theoretical and methodological support for its preparation. Moreover, the development, functions, deficits, and future development of the balance sheet are analyzed in the context of the Chinese system, which provides theoretical and methodological support for the preparation of the natural resources balance sheet and government oversight.

Current and emerging methodologies for estimating carbon sequestration in agricultural soils: A review

This review covers the current and emerging analytical methods used in laboratory, field, landscape and regional contexts for measuring soil organic carbon (SOC) sequestration in agricultural soil. Soil depth plays an important role in estimating SOC sequestration. Selecting appropriate sampling design, depth of soil, use of proper analytical methods and base line selection are prerequisites for estimating accurately the soil carbon stocks. Traditional methods of wet digestion and dry combustion (DC) are extensively used for routine laboratory analysis; the latter is considered to be the "gold standard" and superior to the former for routine laboratory analysis. Recent spectroscopic techniques can measure SOC stocks in laboratory and in-situ even up to a deeper depth. Aerial spectroscopy using multispectral and/or hyperspectral sensors located on aircraft, unmanned aerial vehicles (UAVs) or satellite platforms can measure surface soil organic carbon. Although these techniques' current precision is low, the next generation hyperspectral sensor with improved signal noise ratio will further improve the accuracy of prediction. At the ecosystem level, carbon balance can be estimated directly using the eddy-covariance approach and indirectly by employing agricultural life cycle analysis (LCA). These methods have tremendous potential for estimating SOC. Irrespective of old or new approaches, depending on the resources and research needed, they occupy a unique place in soil carbon and climate research. This paper highlights the overview, potential limitations of various scale-dependent techniques for measuring SOC sequestration in agricultural soil.

Ecosystem Services in Life Cycle Assessment: A novel conceptual framework for soil

Ecosystem Services (ES) are the direct and indirect contributions of ecosystems to human well-being, which include provision of food and water, regulation of flood and erosion processes, soil formation and non-material benefits such as recreation. The integration of ES impact modeling in Life Cycle Assessment (LCA) still has limitations regarding the typology embodied and some conceptual errors in not actually evaluating the benefits provided by ES. In this context, soil is an important resource and provides a wide diversity of ES. Therefore, this article aims to: (i) Review the evolution of ES assessment in LCA and the current methods used to study the biophysical aspects of ES; (ii) Compare the ES cascade model and LCA environmental mechanism for land use impacts; and (iii) Improve and synthesize a new conceptual framework for soil-ES assessment in LCA studies. Results show that the cascade model provides a useful framework for operationalizing ES assessment and should integrate LCA. Thus, this study proposes a new conceptual framework for soil-ES including the main soil processes, functions, services, benefits and values. Each of these cascade model steps is aligned with LCA terminology in order to match the usual midpoint or endpoint levels of modeling. Future works should focus on new indicators to measure the supply of ES and their benefit to humans as well as indicators to their value.

Virtual Water Scarcity Risk to the Global Trade System

Local water scarcity risk (LWSR, meaning potential economic output losses in water-using sectors due to physical water scarcity) can be transmitted to downstream economies through the globalized supply chains. To understand the vulnerability of the global economy to water scarcity, we examine the impacts of local water scarcity risk on the global trade system from 1995 to 2009. We observe increasingly intensified geographical separation between physical water scarcity and production losses due to water scarcity. We identify top nation-sectors in virtual water scarcity risk (VWSR) exports (indicating local water scarcity risk in each nation transmitted to foreign nations through its exports), including agriculture and utilities in major economies such as China, India, Spain, France, and Turkey. These nation-sectors are critical to the resilience of the global economy to water scarcity. We also identify top nation-sectors in virtual water scarcity risk imports (indicating each nation's vulnerability to foreign water scarcity risk through the global trade system), highlighting their vulnerability to distant water scarcity. Our findings reveal the need for nations to collaboratively manage and conserve water resources, and lay the foundation for firms in high VWSR-importing sectors to develop strategies to mitigate such risk.

LCIA framework and cross-cutting issues guidance within the UNEP-SETAC Life Cycle Initiative

Increasing needs for decision support and advances in scientific knowledge within life cycle assessment (LCA) led to substantial efforts to provide global guidance on environmental life cycle impact assessment (LCIA) indicators under the auspices of the UNEP-SETAC Life Cycle Initiative. As part of these efforts, a dedicated task force focused on addressing several LCIA cross-cutting issues as aspects spanning several impact categories, including spatiotemporal aspects, reference states, normalization and weighting, and uncertainty assessment. Here, findings of the cross-cutting issues task force are presented along with an update of the existing UNEP-SETAC LCIA emission-to-damage framework. Specific recommendations are provided with respect to metrics for human health (Disability Adjusted Life Years, DALY) and ecosystem quality (Potentially Disappeared Fraction of species, PDF). Additionally, we stress the importance of transparent reporting of characterization models, reference states, and assumptions, in order to facilitate cross-comparison between chosen methods and indicators. We recommend developing spatially regionalized characterization models, whenever the nature of impacts shows spatial variability and related spatial data are available. Standard formats should be used for reporting spatially differentiated models, and choices regarding spatiotemporal scales should be clearly communicated. For normalization, we recommend using external normalization references. Over the next two years, the task force will continue its effort with a focus on providing guidance for LCA practitioners on how to use the UNEP-SETAC LCIA framework as well as for method developers on how to consistently extend and further improve this framework.

USEEIO: a New and Transparent United States Environmentally-Extended Input-Output Model

National-scope environmental life cycle models of goods and services may be used for many purposes, not limited to quantifying impacts of production and consumption of nations, assessing organization-wide impacts, identifying purchasing hotspots, analyzing environmental impacts of policies, and performing streamlined life cycle assessment. USEEIO is a new environmentally-extended input-output model of the United States fit for such purposes and other sustainable materials management applications. USEEIO melds data on economic transactions between 389 industry sectors with environmental data for these sectors covering land, water, energy and mineral usage and emissions of greenhouse gases, criteria air pollutants, nutrients and toxics, to build a life cycle model of 385 US goods and services. In comparison with existing US models, USEEIO is more current with most data representing year 2013, more extensive in its coverage of resources and emissions, more deliberate and detailed in its interpretation and combination of data sources, and includes formal data quality evaluation and description. USEEIO is assembled with a new Python module called the IO Model Builder capable of assembling and calculating results of user-defined input-output models and exporting the models into LCA software. The model and data quality evaluation capabilities are demonstrated with an analysis of the environmental performance of an average hospital in the US. All USEEIO files are publicly available bringing a new level of transparency for environmentally-extended input-output models.

Assessment of Life Cycle Impacts on Ecosystem Services: Promise, Problems, and Prospects

The analysis of ecosystem services (ES) is becoming a key-factor to implement policies on sustainable technologies. Accordingly, life cycle impact assessment (LCIA) methods are more and more oriented toward the development of harmonized characterization models to address impacts on ES. However, such efforts are relatively recent and have not reached full consensus yet. We investigate here on the transdisciplinary pillars related to the modeling of LCIA on ES by conducting a critical review and comparison of the state-of-the-art in both LCIA and ES domains. We observe that current LCIA practices to assess impacts on "ES provision" suffer from incompleteness in modeling the cause-effect chains; the multifunctionality of ecosystems is omitted; and the "flow" nature of ES is not considered. Furthermore, ES modeling in LCIA is limited by its static calculation framework, and the valuation of ES also experiences some limitations. The conceptualization of land use (changes) as the main impact driver on ES, and the corresponding approaches to retrieve characterization factors, eventually embody several methodological shortcomings, such as the lack of time-dependency and interrelationships between elements in the cause-effect chains. We conclude that future LCIA modeling of ES could benefit from the harmonization with existing integrated multiscale dynamic integrated approaches.

Techno-ecological synergy: a framework for sustainable engineering

Even though the importance of ecosystems in sustaining all human activities is well-known, methods for sustainable engineering fail to fully account for this role of nature. Most methods account for the demand for ecosystem services, but almost none account for the supply. Incomplete accounting of the very foundation of human well-being can result in perverse outcomes from decisions meant to enhance sustainability and lost opportunities for benefiting from the ability of nature to satisfy human needs in an economically and environmentally superior manner. This paper develops a framework for understanding and designing synergies between technological and ecological systems to encourage greater harmony between human activities and nature. This framework considers technological systems ranging from individual processes to supply chains and life cycles, along with corresponding ecological systems at multiple spatial scales ranging from local to global. The demand for specific ecosystem services is determined from information about emissions and resource use, while the supply is obtained from information about the capacity of relevant ecosystems. Metrics calculate the sustainability of individual ecosystem services at multiple spatial scales and help define necessary but not sufficient conditions for local and global sustainability. Efforts to reduce ecological overshoot encourage enhancement of life cycle efficiency, development of industrial symbiosis, innovative designs and policies, and ecological restoration, thus combining the best features of many existing methods. Opportunities for theoretical and applied research to make this framework practical are also discussed.

Emergy evaluation using the calculation software SCALE: case study, added value and potential improvements

This paper reports the emergy-based evaluation (EME) of the ecological performance of four water treatment plants (WTPs) using three different approaches. The results obtained using the emergy calculation software SCALE (EMESCALE) are compared with those achieved through a conventional emergy evaluation procedure (EMECONV), as well as through the application of the Solar Energy Demand (SED) method. SCALE's results are based on a detailed representation of the chain of technological processes provided by the lifecycle inventory database ecoinvent®. They benefit from a higher level of details in the description of the technological network as compared to the ones calculated with a conventional EME and, unlike the SED results, are computed according to the emergy algebra rules. The analysis delves into the quantitative comparison of unit emergy values (UEVs) for individual technospheric inputs provided by each method, demonstrating the added value of SCALE to enhance reproducibility, accurateness and completeness of an EME. However, SCALE cannot presently include non-technospheric inputs in emergy accounting, like e.g. human labor and ecosystem services. Moreover, SCALE is limited by the approach used to build the dataset of UEVs for natural resources. Recommendations on the scope and accuracy of SCALE-based emergy accounting are suggested for further steps in software development, as well as preliminary quantitative methods to account for ecosystem services and human labor.

Assessing the critical role of ecological goods and services in microalgal biofuel life cycles

This pioneering study utilizes a hierarchical thermodynamic-based resource aggregation scheme to quantify the contribution of ecosystem goods and services to emerging microalgal biofuels life cycles.

Revision and extension of Eco-LCA metrics for sustainability assessment of the energy and chemical processes

Ecologically based life cycle assessment (Eco-LCA) is an appealing approach for the evaluation of resources utilization and environmental impacts of the process industries from an ecological scale. However, the aggregated metrics of Eco-LCA suffer from some drawbacks: the environmental impact metric has limited applicability; the resource utilization metric ignores indirect consumption; the renewability metric fails to address the quantitative distinction of resources availability; the productivity metric seems self-contradictory. In this paper, the existing Eco-LCA metrics are revised and extended for sustainability assessment of the energy and chemical processes. A new Eco-LCA metrics system is proposed, including four independent dimensions: environmental impact, resource utilization, resource availability, and economic effectiveness. An illustrative example of comparing assessment between a gas boiler and a solar boiler process provides insight into the features of the proposed approach.

Quantifying the environmental impact of an integrated human/industrial-natural system using life cycle assessment; a case study on a forest and wood processing chain

Life Cycle Assessment (LCA) is a tool to assess the environmental sustainability of a product; it quantifies the environmental impact of a product's life cycle. In conventional LCAs, the boundaries of a product's life cycle are limited to the human/industrial system, the technosphere. Ecosystems, which provide resources to and take up emissions from the technosphere, are not included in those boundaries. However, similar to the technosphere, ecosystems also have an impact on their (surrounding) environment through their resource usage (e.g., nutrients) and emissions (e.g., CH4). We therefore propose a LCA framework to assess the impact of integrated Techno-Ecological Systems (TES), comprising relevant ecosystems and the technosphere. In our framework, ecosystems are accounted for in the same manner as technosphere compartments. Also, the remediating effect of uptake of pollutants, an ecosystem service, is considered. A case study was performed on a TES of sawn timber production encompassing wood growth in an intensively managed forest ecosystem and further industrial processing. Results show that the managed forest accounted for almost all resource usage and biodiversity loss through land occupation but also for a remediating effect on human health, mostly via capture of airborne fine particles. These findings illustrate the potential relevance of including ecosystems in the product's life cycle of a LCA, though further research is needed to better quantify the environmental impact of TES.

Accounting for the biogeochemical cycle of nitrogen in input-output life cycle assessment

Nitrogen is indispensable for sustaining human activities through its role in the production of food, animal feed, and synthetic chemicals. This has encouraged significant anthropogenic mobilization of reactive nitrogen and its emissions into the environment resulting in severe disruption of the nitrogen cycle. This paper incorporates the biogeochemical cycle of nitrogen into the 2002 input-output model of the U.S. economy. Due to the complexity of this cycle, this work proposes a unique classification of nitrogen flows to facilitate understanding of the interaction between economic activities and various flows in the nitrogen cycle. The classification scheme distinguishes between the mobilization of inert nitrogen into its reactive form, use of nitrogen in various products, and nitrogen losses to the environment. The resulting inventory and model of the US economy can help quantify the direct and indirect impacts or dependence of economic sectors on the nitrogen cycle. This paper emphasizes the need for methods to manage the N cycle that focus not just on N losses, which has been the norm until now, but also include other N flows for a more comprehensive view and balanced decisions. Insight into the N profile of various sectors of the 2002 U.S. economy is presented, and the inventory can also be used for LCA or Hybrid LCA of various products. The resulting model is incorporated in the approach of Ecologically-Based LCA and available online.

LCA and emergy accounting of aquaculture systems: towards ecological intensification

An integrated approach is required to optimise fish farming systems by maximising output while minimising their negative environmental impacts. We developed a holistic approach to assess the environmental performances by combining two methods based on energetic and physical flow analysis. Life Cycle Assessment (LCA) is a normalised method that estimates resource use and potential impacts throughout a product's life cycle. Emergy Accounting (EA) refers the amount of energy directly or indirectly required by a product or a service. The combination of these two methods was used to evaluate the environmental impacts of three contrasting fish-farming systems: a farm producing salmon in a recirculating system (RSF), a semi-extensive polyculture pond (PF1) and an extensive polyculture pond (PF2). The RSF system, with a low feed-conversion ratio (FCR = 0.95), had lower environmental impacts per tonne of live fish produced than did the two pond farms, when the effects on climate change, acidification, total cumulative energy demand, land competition and water dependence were considered. However, RSF was clearly disconnected from the surrounding environment and depended highly on external resources (e.g. nutrients, energy). Ponds adequately incorporated renewable natural resources but had higher environmental impacts due to incomplete use of external inputs. This study highlighted key factors necessary for the successful ecological intensification of fish farming, i.e., minimise external inputs, lower the FCR, and increase the use of renewable resources from the surrounding environment. The combination of LCA and EA seems to be a practical approach to address the complexity of optimising biophysical efficiency in aquaculture systems.

Multi-scale modeling for sustainable chemical production

With recent advances in metabolic engineering, it is now technically possible to produce a wide portfolio of existing petrochemical products from biomass feedstock. In recent years, a number of modeling approaches have been developed to support the engineering and decision-making processes associated with the development and implementation of a sustainable biochemical industry. The temporal and spatial scales of modeling approaches for sustainable chemical production vary greatly, ranging from metabolic models that aid the design of fermentative microbial strains to material and monetary flow models that explore the ecological impacts of all economic activities. Research efforts that attempt to connect the models at different scales have been limited. Here, we review a number of existing modeling approaches and their applications at the scales of metabolism, bioreactor, overall process, chemical industry, economy, and ecosystem. In addition, we propose a multi-scale approach for integrating the existing models into a cohesive framework. The major benefit of this proposed framework is that the design and decision-making at each scale can be informed, guided, and constrained by simulations and predictions at every other scale. In addition, the development of this multi-scale framework would promote cohesive collaborations across multiple traditionally disconnected modeling disciplines to achieve sustainable chemical production.

Techno-ecological synergy as a path toward sustainability of a North American residential system

For any human-designed system to be sustainable, ecosystem services that support it must be readily available. This work explicitly accounts for this dependence by designing synergies between technological and ecological systems. The resulting techno-ecological network mimics nature at the systems level, can stay within ecological constraints, and can identify novel designs that are economically and environmentally attractive that may not be found by the traditional design focus on technological options. This approach is showcased by designing synergies for a typical American suburban home at local and life cycle scales. The objectives considered are carbon emissions, water withdrawal, and cost savings. Systems included in the design optimization include typical ecosystems in suburban yards: lawn, trees, water reservoirs, and a vegetable garden; technological systems: heating, air conditioning, faucets, solar panels, etc.; and behavioral variables: heating and cooling set points. The ecological and behavioral design variables are found to have a significant effect on the three objectives, in some cases rivaling and exceeding the effect of traditional technological options. These results indicate the importance and benefits of explicitly including ecosystems in the design of sustainable systems, something that is rarely done in existing methods.

A meta-analytic review of life cycle assessment and flow analyses studies of palm oil biodiesel

This work reviews and performs a meta-analysis of the recent life cycle assessment and flow analyses studies palm oil biodiesel. The best available data and information are extracted, summarized, and discussed. Most studies found palm oil biodiesel would produce positive energy balance with an energy ratio between 2.27 and 4.81, and with a net energy production of 112 GJ ha(-1) y(-1). With the exception of a few studies, most conclude that palm oil biodiesel is a net emitter of greenhouse gases (GHG). The origin of oil palm plantation (planted area) is the foremost determinant of GHG emissions and C payback time (CPBT). Converting peatland forest results in GHG emissions up to 60 tons CO(2) equivalent (eq) ha(-1) y(-1) leading to 420 years of CPBT. In contrast, converting degraded land or grassland for plantation can positively offset the system to become a net sequester of 5 tons CO(2) eq ha(-1) y(-1). Few studies have discussed cradle-to-grave environmental impacts such as acidification, eutrophication, toxicity, and biodiversity, which open opportunity for further studies.

Improvements to Emergy evaluations by using Life Cycle Assessment

Life Cycle Assessment (LCA) is a widely recognized, multicriteria and standardized tool for environmental assessment of products and processes. As an independent evaluation method, emergy assessment has shown to be a promising and relatively novel tool. The technique has gained wide recognition in the past decade but still faces methodological difficulties which prevent it from being accepted by a broader stakeholder community. This review aims to elucidate the fundamental requirements to possibly improve the Emergy evaluation by using LCA. Despite its capability to compare the amount of resources embodied in production systems, Emergy suffers from its vague accounting procedures and lacks accuracy, reproducibility, and completeness. An improvement of Emergy evaluations can be achieved via (1) technical implementation of Emergy algebra in the Life Cycle Inventory (LCI); (2) selection of consistent Unit Emergy Values (UEVs) as characterization factors for Life Cycle Impact Assessment (LCIA); and (3) expansion of the LCI system boundaries to include supporting systems usually considered by Emergy but excluded in LCA (e.g., ecosystem services and human labor). Whereas Emergy rules must be adapted to life-cycle structures, LCA should enlarge its inventory to give Emergy a broader computational framework. The matrix inversion principle used for LCAs is also proposed as an alternative to consistently account for a large number of resource UEVs.

Assessing resource intensity and renewability of cellulosic ethanol technologies using eco-LCA

Recognizing the contributions of ecosystem services and the lack of their comprehensive accounting in life cycle assessment (LCA), an in-depth analysis of their contribution in the life cycle of cellulosic ethanol derived from five different feedstocks was conducted, with gasoline and corn ethanol as reference fuels. The relative use intensity of natural resources encompassing land and ecosystem goods and services by cellulosic ethanol was estimated using the Eco-LCA framework. Despite being resource intensive compared to gasoline, cellulosic ethanol offers the possibility of a reduction in crude oil consumption by as much as 96%. Soil erosion and land area requirements can be sources of concern for cellulosic ethanol derived directly from managed agriculture. The analysis of two broad types of thermodynamic metrics, namely: various types of physical return on investment and a renewability index, which indicate competitiveness and sustainability of cellulosic ethanol, respectively, show that only ethanol from waste resources combines a favorable thermodynamic return on investment with a higher renewability index. However, the production potential of ethanol from waste resources is limited. This finding conveys a possible dilemma of biofuels: combining high renewability, high thermodynamic return on investment, and large production capacity may remain elusive. A plot of renewability versus energy return on investment is suggested as one of the options for providing guidance on future biofuel selection.

Resource management as a key factor for sustainable urban planning

Due to fast urbanization and increasing living standards, the environmental sustainability of our global society becomes more and more questionable. In this historical review we investigate the role of resources management (RM) and urban planning (UP) and propose ways for integration in sustainable development (SD). RM follows the principle of circular causation, and we reflect on to what extent RM has been an element for urban planning. Since the existence of the first settlements, a close relationship between RM, urbanization and technological development has been present. RM followed the demand for urban resources like water, energy, and food. In history, RM has been fostered by innovation and technology developments and has driven population growth and urbanization. Recent massive resource demand, especially in relation to energy and material flows, has altered natural ecosystems and has resulted in environmental degradation. UP has developed separately in response to different questions. UP followed the demand for improved living conditions, often associated to safety, good manufacturing and trading conditions and appropriate sanitation and waste management. In history UP has been a developing research area, especially since the industrial era and the related strong urbanization at the end of the 18th century. UP responded to new emerging problems in urban areas and became increasingly complex. Nowadays, UP has to address many objectives that are often conflicting, including, the urban sustainability. Our current urban un-sustainability is rooted in massive resource consumption and waste production beyond natural limits, and the absence of flows from waste to resources. Therefore, sustainable urban development requires integration of RM into UP. We propose new ways to this integration.

Solar energy demand (SED) of commodity life cycles

The solar energy demand (SED) of the extraction of 232 atmospheric, biotic, fossil, land, metal, mineral, nuclear, and water resources was quantified and compared with other energy- and exergy-based indicators. SED represents the direct and indirect solar energy required by a product or service during its life cycle. SED scores were calculated for 3865 processes, as implemented in the Ecoinvent database, version 2.1. The results showed that nonrenewable resources, and in particular minerals, formed the dominant contribution to SED. This large share is due to the indirect solar energy required to produce these resource inputs. Compared with other energy- and exergy-based indicators, SED assigns higher impact factors to minerals and metals and smaller impact factors to fossil energetic resources, land use, and nuclear energy. The highest differences were observed for biobased and renewable energy generation processes, whose relative contribution of renewable resources such as water, biomass, and land occupation was much lower in SED than in energy- and exergy-based indicators.