What Is a Life Cycle Assessment and Why Does It Matter for Recycling?
Discussions regarding environmental impacts of products or technologies often refer to something called a “Life Cycle Assessment,” or LCA.
LCAs are widely used to help evaluate potential environmental impacts of products, materials, and processes over their lifetime. LCAs have recently been used to assess performance attributes of advanced recycling technologies such as pyrolysis, depolymerization, and dissolution.
What Does an LCA Measure?
LCAs typically look at different stages of a product or process, which may include:
raw material extraction
manufacturing
transportation
product use
recycling
and end-of-life management
Depending on the study, an LCA may evaluate environmental impact on categories such as:
Air (e.g., greenhouse gas emissions, global warming potential, ozone depletion, smog formation),
· Energy (e.g., resource use, fossil fuel depletion)
· Water (overall consumption, eutrophication, acidification)
· Human health impacts (e.g., respiratory effects, toxicity)
· Ecotoxicity
LCAs, when conducted transparently with clearly stated assumptions, system boundaries, methodologies, and context for interpreting results, can help researchers, companies, and policymakers better understand tradeoffs, identify opportunities for improvement, and compare different approaches within complex systems.
Why Can Different LCAs Reach Different Conclusions?
One of the most important things to understand about LCAs is that results depend heavily on the assumptions, data sources, and boundaries used in the study.
Three factors often have a particularly significant influence on LCA results:
System Boundaries: What stages of the product or process are included or excluded from the analysis?
Mass and Energy Inventories: What data is used to represent material inputs, energy consumption, emissions, and process performance?
Database and Modeling Assumptions: Which life-cycle inventory database and version is used, and what underlying assumptions are embedded within those datasets?
Even when evaluating the same technology, different assumptions can lead to different results. This is why transparency and context are essential when interpreting LCA findings.
Understanding “Avoided Emissions”
One concept that often appears in LCAs for advanced recycling is “avoided emissions.”
This refers to emissions that may be reduced when one process replaces another. For example, some studies evaluate whether advanced recycling could reduce emissions compared to landfill disposal, incineration, or producing materials from virgin resources.
These comparisons can provide useful insights, but they also depend heavily on:
system boundaries
baseline assumptions
energy sources
conversion efficiencies
and how outputs are ultimately used
Because of this, avoided emissions calculations should be interpreted carefully and transparently.
LCAs Are One Tool, Not the Entire Answer
LCAs can provide valuable information, but they also have limitations and uncertainties. In complex interdependent systems, there is rarely a single metric or study that captures all environmental, economic, and societal tradeoffs. Traditional LCAs focus primarily on environmental impact categories and do not include life cycle costing, life cycle economics, or societal life cycle assessment metrics, unless those are conducted separately. Consequently, LCAs should be viewed as one component of a broader decision-making framework, rather than a comprehensive measure or assessment of overall systems' performance.
Because LCAs are influenced by assumptions, system boundaries, data sources, methodologies, and interpretation, they are most useful as decision-support tools, rather than definitive measures of the environmental performance. Their greatest value lies in helping decision-makers better understand tradeoffs, identify opportunities for improvement, and evaluate potential consequences across a system.
As discussions around advanced recycling continue evolving, LCAs will undoubtedly remain an important tool for evaluating technologies, understanding tradeoffs, and supporting more informed discussions around recycling and waste management systems.