What are the limitations of LCA for assessing complex and dynamic systems?

1 Scope definition

One of the first challenges of LCA is to define the scope and boundaries of the system under study. This involves deciding what life cycle stages, processes, inputs, outputs, and impacts to include or exclude from the analysis. Depending on the goal and scope of the study, different choices can lead to different results and interpretations. For example, should LCA include the social and economic aspects of the system, or only focus on the environmental ones? Should LCA consider the upstream and downstream impacts of the system, or only the direct ones? Should LCA account for the temporal and spatial variations of the system, or use average or generic data?

2 Data availability and quality

Another challenge of LCA is to collect and use reliable and relevant data for the system under study. Data availability and quality can vary depending on the source, method, and level of detail of the data. For example, some data may be proprietary, confidential, or inaccessible, limiting the transparency and reproducibility of LCA. Some data may be outdated, incomplete, or inconsistent, affecting the accuracy and validity of LCA. Some data may be too aggregated or disaggregated, making it difficult to match the system boundaries and functional unit of LCA. Data quality can also influence the uncertainty and sensitivity of LCA results, requiring appropriate methods to handle and communicate them.

3 Impact assessment methods

A third challenge of LCA is to select and apply suitable impact assessment methods for the system under study. Impact assessment methods are used to translate the inventory data into indicators of potential environmental impacts, such as global warming, acidification, eutrophication, etc. However, there are many different methods available, each with its own assumptions, models, and value choices. For example, some methods may use different characterization factors, weighting factors, or normalization factors, resulting in different impact scores and rankings. Some methods may cover different impact categories, midpoint indicators, or endpoint indicators, reflecting different perspectives and priorities. Some methods may be more or less applicable to specific systems, regions, or contexts, affecting the relevance and completeness of LCA.

4 System dynamics and feedbacks

A fourth challenge of LCA is to account for the system dynamics and feedbacks that affect the system under study. System dynamics and feedbacks refer to the changes and interactions that occur within and between the system components over time, such as production, consumption, recycling, innovation, etc. These changes and interactions can influence the inputs and outputs of the system, as well as its environmental impacts. However, LCA often assumes a static and linear system, ignoring or simplifying the dynamic and nonlinear aspects of the system. For example, LCA may not capture the rebound effects, substitution effects, or learning effects that can occur as a result of changes in the system. LCA may also not account for the temporal and spatial heterogeneity of the system, such as seasonal variations, regional differences, or spatial allocation.

5 Trade-offs and optimization

A fifth challenge of LCA is to deal with the trade-offs and optimization that arise from the system under study. Trade-offs and optimization refer to the conflicts and synergies that exist among the different environmental impacts, as well as among the environmental, social, and economic aspects of the system. These conflicts and synergies can affect the decision-making and policy-making processes based on LCA results. However, LCA often does not provide a clear and consistent way to address these trade-offs and optimization. For example, LCA may not consider the preferences, values, and objectives of the stakeholders involved in the system. LCA may also not account for the uncertainty, variability, and complexity of the system, such as scenario analysis, multi-criteria analysis, or life cycle costing.

6 Improvement opportunities

A sixth challenge of LCA is to identify and implement improvement opportunities for the system under study. Improvement opportunities refer to the actions and strategies that can reduce the environmental impacts of the system, such as eco-design, eco-innovation, eco-efficiency, etc. These actions and strategies can help achieve the goals and benefits of LCA, such as environmental performance, cost savings, competitive advantage, etc. However, LCA often does not provide sufficient and specific guidance on how to identify and implement these improvement opportunities. For example, LCA may not consider the feasibility, acceptability, and effectiveness of the improvement options. LCA may also not account for the barriers, drivers, and incentives that can influence the adoption and diffusion of the improvement options.

7 Here’s what else to consider

This is a space to share examples, stories, or insights that don’t fit into any of the previous sections. What else would you like to add?