Illustration impacts and criticalities of metals

Impacts and criticalities of metals: towards a hybrid approach combining LCA and qualitative analysis


As an expert firm specializing in the environmental and social performance of businesses, EVEA consistently engages in R&D, particularly in developing new services aligned with organizational needs. Collaboration with stakeholders such as public authorities, companies, and ACV-specialized associations is crucial for finding optimal solutions.


Life Cycle Assessment (LCA) has established itself as the benchmark quantitative environmental assessment method. It evaluates the potential impacts of a product, service, or activity throughout its life cycle using a multi-criteria approach.


Enhancing this analysis with methods offering a more precise perspective on specific environmental issues is highly beneficial, especially concerning the depletion of non-renewable mineral and metal resources.


In the contextual elements of the 2009 Guidelines for Social Life Cycle Assessment (SLCA), the United Nations Environment Programme (UNEP) summarizes its vision of sustainable development as follows: ‘(…) a society develops socially and economically within an environment-influenced context, and [that] this development passes through the political system. Furthermore, regardless of the place or time, a society maintains its cohesion through its cultural characteristics.’ (Mazijn, 1994b).


According to UNEP, natural capital thus conditions the development of other capitals (social/human, economic/financial, technological, etc.). Managing resource flows and consumption, which can be exploited unsustainably and generate significant pollution, is vital. This is where Life Cycle Assessment (LCA) becomes crucial. By modeling all inflows and outflows over the life cycle of a product/service, it provides an environmental impact assessment (multi-criteria) with a 'life cycle' perspective, offering insights into the sustainability of the evaluated product, service, or activity.




In its foreword, the 2019 ‘Global Resources Outlook report by the International Resource Panel (IRP, affiliated with UNEP) reveals key figures on raw materials:


  • Since 1970, GDP has quadrupled, the population has doubled, and resource consumption has tripled.
  • 90% of biodiversity loss, water stress, and 50% of greenhouse gas emissions are attributed to the extraction and processing of natural resources (biomass, fossil fuels, minerals, etc.).
  • The material footprint per capita in high-income countries is 60% higher that of middle-income countries and 13 times higher than that of low-income countries.


Material producitivity has increased less rapidly than labor and energy productivity. it even declined in the 2000s and has since plateaued (see graph below).


Regarding metals specifically, the average annual growth in consumption between 1970 and 2017 was 2.7% (3 to 9 billion tons).


Schéma de la Global material extraction and material productivity

Figure 1: extrait du "Global resources outlook" - UNEP et IRP - 2019




Metals may not be the most consumed resource globally, but they generate significant impacts.


In this regard, the authors of the report ‘Global Resource Outlook’ and those of the report titled ‘Mining Controversies - Putting an End to Certain Misrepresentations about Mining and Mineral Supply Chains’ by the Systext association in 2021 agree that extraction techniques lead to increasingly harmful impacts on the environment and human health due to the growing difficulty of accessing deposits (lower density, farther, deeper), requiring increased energy, chemical, and water consumption.


This also explains the criticality issues associated with raw materials, particularly metals.


Two criticality approaches are distinguished:


  • Economic and geopolitical approach: predominantly used to manage short- and medium-term supply risks, with a regularly updated list of critical materials.
  • Geological and physical approach: used to estimate the rarity or criticality of the resource (concentration in the Earth's crust). It is notably considered by BRGM to define what constitutes a critical substance (more or less rare and/or strategic from an economic perspective).


Evaluating the environmental impact related to the depletion of non-renewable resources in LCA relies on these different approaches, each aiming to measure and quantify the pressure exerted on these resources.


Each approach involves specific methodological choices.


For example, within the framework of the Environmental Footprint (EF) method by the European Commission, the "Resource use minerals and metals" indicator is based on the resource depletion rate. It estimates resource depletion by calculating a ratio between the resource extraction rate and the available reserves for it [used in the CML-IA and Anthropogenic stock extended Abiotic Depletion Potential (AADP) methods].


The characterization factors of these methods vary depending on the type of reserves studied (ultimate, reserve bases, economic).


Figure 2: EF method indicators and robustness levels – 'Development of a weighting approach for the Environmental Footprint' 2018


Nevertheless, experts from the European Commission who developed the EF method, in which this indicator is integrated, identified low robustness for it. This observation emphasizes the need to approach Life Cycle Assessment results with caution and the importance of enriching the analysis with complementary assessment tools or other impact models in LCA, such as the Recipe model, for instance.



Why does this indicator show low robustness?


Firstly, the lack of consensus within the scientific community regarding the characterization method to assess resource depletion creates inherent uncertainty in defining the environmental problem related to resource use in LCA. Secondly, the complexity of ensuring certainties about the real reserves of producing countries, especially for fossil resources, faces challenges such as the reliability of available data and geopolitical issues.

In this context, enriching environmental LCA with a comprehensive analysis encompassing other sustainability pillars proves relevant.




At EVEA, we offer three types of analyses complementary to "classic" environmental LCA:


Our three proposals to complement the environmental LCA:


  • Prospective LCA 2050: using characterization factors recalculated by Score LCA, focusing on the "depletion of mineral resources" indicator.
  • Social footprint: expertise and references in assessing social issues throughout the life cycle, with dedicated databases and methods (for more information, visit our ASCV-dedicated webpage).
  • Specific criticality analysis of your materials and business model: enhancing company resilience through sourcing and procurement using the appropriate criticality matrix (supply risks by country, company vulnerability).
  • Putting things into perspective by integrating other impact models in LCA analysis.





For further/complementary information, visit:


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