Summary
The diversity of raw materials used in modern products, compounded by the risk of supply disruptions—due to uneven geological distribution of resources, along with socioeconomic factors like ...production concentration and political (in)stability of raw material producing countries—has drawn attention to the subject of raw material “criticality.” In this article, we review the state of the art regarding the integration of criticality assessment, herein termed “product‐level supply risk assessment,” as a complement to environmental life cycle assessment. We describe and compare three methods explicitly developed for this purpose—Geopolitical Supply Risk (GeoPolRisk), Economic Scarcity Potential (ESP), and the Integrated Method to Assess Resource Efficiency (ESSENZ)—based on a set of criteria including considerations of data sources, uncertainties, and other contentious methodological aspects. We test the methods on a case study of a European‐manufactured electric vehicle, and conclude with guidance for appropriate application and interpretation, along with opportunities for further methodological development. Although the GeoPolRisk, ESP, and ESSENZ methods have several limitations, they can be useful for preliminary assessments of the potential impacts of raw material supply risks on a product system (i.e., “outside‐in” impacts) alongside the impacts of a product system on the environment (i.e., “inside‐out” impacts). Care is needed to not overlook critical raw materials used in small amounts but nonetheless important to product functionality. Further methodological development could address regional and firm‐level supply risks, multiple supply‐chain stages, and material recycling, while improving coverage of supply risk characterization factors.
Purpose
The safeguard subject of the Area of Protection “natural Resources,” particularly regarding mineral resources, has long been debated. Consequently, a variety of life cycle impact assessment ...methods based on different concepts are available. The Life Cycle Initiative, hosted by the UN Environment, established an expert task force on “Mineral Resources” to review existing methods (this article) and provide guidance for application-dependent use of the methods and recommendations for further methodological development (Berger et al. in Int J Life Cycle Assess,
2020
).
Methods
Starting in 2017, the task force developed a white paper, which served as its main input to a SETAC Pellston Workshop® in June 2018, in which a sub-group of the task force members developed recommendations for assessing impacts of mineral resource use in LCA. This article, based mainly on the white paper and pre-workshop discussions, presents a thorough review of 27 different life cycle impact assessment methods for mineral resource use in the “natural resources” area of protection. The methods are categorized according to their basic impact mechanisms, described and compared, and assessed against a comprehensive set of criteria.
Results and discussion
Four method categories have been identified and their underlying concepts are described based on existing literature: depletion methods, future efforts methods, thermodynamic accounting methods, and supply risk methods. While we consider depletion and future efforts methods more “traditional” life cycle impact assessment methods, thermodynamic accounting and supply risk methods are rather providing complementary information. Within each method category, differences between methods are discussed in detail, which allows for further sub-categorization and better understanding of what the methods actually assess.
Conclusions
We provide a thorough review of existing life cycle impact assessment methods addressing impacts of mineral resource use, covering a broad overview of basic impact mechanisms to a detailed discussion of method-specific modeling. This supports a better understanding of what the methods actually assess and highlights their strengths and limitations. Building on these insights, Berger et al. (Int J Life Cycle Assess,
2020
) provide recommendations for application-dependent use of the methods, along with recommendations for further methodological development.
Purpose
In this paper, we summarize the discussion and present the findings of an expert group effort under the umbrella of the United Nations Environment Programme (UNEP)/Society of Environmental ...Toxicology and Chemistry (SETAC) Life Cycle Initiative proposing natural resources as an Area of Protection (AoP) in Life Cycle Impact Assessment (LCIA).
Methods
As a first step, natural resources have been defined for the LCA context with reference to the overall UNEP/SETAC Life Cycle Impact Assessment (LCIA) framework. Second, existing LCIA methods have been reviewed and discussed. The reviewed methods have been evaluated according to the considered type of natural resources and their underlying principles followed (use-to-availability ratios, backup technology approaches, or thermodynamic accounting methods).
Results and discussion
There is currently no single LCIA method available that addresses impacts for all natural resource categories, nor do existing methods and models addressing different natural resource categories do so in a consistent way across categories. Exceptions are exergy and solar energy-related methods, which cover the widest range of resource categories. However, these methods do not link exergy consumption to changes in availability or provisioning capacity of a specific natural resource (e.g., mineral, water, land etc.). So far, there is no agreement in the scientific community on the most relevant type of future resource indicators (depletion, increased energy use or cost due to resource extraction, etc.). To address this challenge, a framework based on the concept of stock/fund/flow resources is proposed to identify, across natural resource categories, whether depletion/dissipation (of stocks and funds) or competition (for flows) is the main relevant aspect.
Conclusions
An LCIA method—or a set of methods—that consistently address all natural resource categories is needed in order to avoid burden shifting from the impact associated with one resource to the impact associated with another resource. This paper is an important basis for a step forward in the direction of consistently integrating the various natural resources as an Area of Protection into LCA.
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.
Purpose
While many examples have shown unsustainable use of freshwater resources, existing LCIA methods for water use do not comprehensively address impacts to natural resources for future ...generations. This framework aims to (1) define freshwater resource as an item to protect within the Area of Protection (AoP) natural resources, (2) identify relevant impact pathways affecting freshwater resources, and (3) outline methodological choices for impact characterization model development.
Methods
Considering the current scope of the AoP natural resources, the complex nature of freshwater resources and its important dimensions to safeguard safe future supply, a definition of freshwater resource is proposed, including water quality aspects. In order to clearly define what is to be protected, the freshwater resource is put in perspective through the lens of the three main safeguard subjects defined by Dewulf et al. (
2015
). In addition, an extensive literature review identifies a wide range of possible impact pathways to freshwater resources, establishing the link between different inventory elementary flows (water consumption, emissions, and land use) and their potential to cause long-term freshwater depletion or degradation.
Results and discussion
Freshwater as a resource has a particular status in LCA resource assessment. First, it exists in the form of three types of resources: flow, fund, or stock. Then, in addition to being a resource for human economic activities (e.g., hydropower), it is above all a non-substitutable support for life that can be affected by both consumption (source function) and pollution (sink function). Therefore, both types of elementary flows (water consumption and emissions) should be linked to a damage indicator for freshwater as a resource. Land use is also identified as a potential stressor to freshwater resources by altering runoff, infiltration, and erosion processes as well as evapotranspiration. It is suggested to use the concept of recovery period to operationalize this framework: when the recovery period lasts longer than a given period of time, impacts are considered to be irreversible and fall into the concern of freshwater resources protection (i.e., affecting future generations), while short-term impacts effect the AoP ecosystem quality and human health directly. It is shown that it is relevant to include this concept in the impact assessment stage in order to discriminate the long-term from the short-term impacts, as some dynamic fate models already do.
Conclusions
This framework provides a solid basis for the consistent development of future LCIA methods for freshwater resources, thereby capturing the potential long-term impacts that could warn decision makers about potential safe water supply issues in the future.
There are currently limited life cycle impact assessment methods existing for assessing impacts on the natural resource soil. In this paper, we develop methods for the assessment of compaction and ...water erosion impacts within one framework, which can be expanded with additional degradation processes in the future. Our methods assess potential long-term impacts from agricultural activities on the production capacity of soils and are able to distinguish between different management choices such as machinery selection and tillage practices. Characterization factors are provided as global raster data sets at high spatial resolution (∼1 km) and for larger geographic units including uncertainties of spatial aggregation. Uncertainties due to variability of climate and weather are provided where possible. The application of the methods is demonstrated and discussed in a simplified case study. Results show that in a highly mechanized scenario of global agriculture without any conservation measures, long-term yearly soil productivity losses due to compaction and water erosion can amount to up to double-digit percentages for major crops. This confirms the relevance of compaction and water erosion impacts for agricultural LCAs.
The concept of criticality has been used to assess whether a resource may become a limiting factor to economic activities. It has been primarily applied to nonrenewable resources, in particular to ...metals. However, renewable resources such as water may also be overused and become a limiting factor. In this paper, we therefore developed a water criticality method that allows for a new, user-oriented assessment of water availability and accessibility. Comparability of criticality across resources is desirable, which is why the presented adaptation of the criticality approach to water is based on a metal criticality method, whose basic structure is maintained. With respect to the necessary adaptations to the water context, a transparent water criticality framework is proposed that may pave the way for future integrated criticality assessment of metals, water, and other resources. Water criticality scores were calculated for 159 countries subdivided into 512 geographic units for the year 2000. Results allow for a detailed analysis of criticality profiles, revealing locally specific characteristics of water criticality. This is useful for the screening of sites and their related water criticality, for indication of water related problems and possible mitigation options and water policies, and for future water scenario analysis.
Maintaining biotic capacity is of key importance with regard to global food and biomass provision. One reason for productivity loss is soil compaction. In this paper, we use a statistical empirical ...model to assess long-term yield losses through soil compaction in a regionalized manner, with global coverage and for different agricultural production systems. To facilitate the application of the model, we provide an extensive dataset including crop production data (with 81 crops and corresponding production systems), related machinery application, as well as regionalized soil texture and soil moisture data. Yield loss is modeled for different levels of soil depth (0–25cm, 25–40cm and >40cm depth). This is of particular relevance since compaction in topsoil is classified as reversible in the short term (approximately four years), while recovery of subsoil layers takes much longer. We derive characterization factors quantifying the future average annual yield loss as a fraction of the current yield for 100years and applicable in Life Cycle Assessment studies of agricultural production. The results show that crops requiring enhanced machinery inputs, such as potatoes, have a major influence on soil compaction and yield losses, while differences between mechanized production systems (organic and integrated production) are small. The spatial variations of soil moisture and clay content are reflected in the results showing global hotspot regions especially susceptible to soil compaction, e.g. the South of Brazil, the Caribbean Islands, Central Africa, and the Maharashtra district of India. The impacts of soil compaction can be substantial, with highest annual yield losses in the range of 0.5% (95% percentile) due to one year of potato production (cumulated over 100y this corresponds to a one-time loss of 50% of the present yield). These modeling results demonstrate the necessity for including soil compaction effects in Life Cycle Impact Assessment.
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•Presentation of a method to assess soil compaction in Life Cycle Impact Assessment•Quantification of the soil compaction impact in % yield loss for crop production•Applicability of the method to various spatial scales and production systems•Adapting the crop in mechanized systems is effective in reducing compaction impact.•Vulnerability to compaction impact is highest in moist soil with high clay content.
Although metals and minerals represent a prominent asset for sustainable development, continuous population growth and the current accelerations in energy and mobility transitions are increasing ...concerns regarding their accessibility for current and future generations. As recent insights have identified access rather than depletion to be the dominant factor for resources, this paper elaborates on the (in)accessibility concept of such raw materials once they have entered the technosphere. It identifies six human actions that compromise accessibility: emitting, landfilling, tailing, downcycling, hoarding and abandoning. It analyses the degree of the generated inaccessibility and proposes estimated duration of inaccessibility as a proxy. It further explores how current sustainability management tools like material flow analysis and life cycle analysis could be further developed to address resource (in)accessibility. Finally, the paper presents a case study on cobalt in the EU, where five compromising actions make 70% of the extracted cobalt inaccessible due to tailings (21.3%), landfilling (31.2%), downcycling (11.6%), dissipation (1.4%) and hoarding (4.3%); only 30% is used to expand the functional stock.
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