Life Cycle Assessment (LCA)
Also known as: Life Cycle Analysis, Cradle-to-Grave Analysis, Ecobalance, Yaşam Döngüsü Değerlendirmesi
Life Cycle Assessment is a systematic, ISO-standardized methodology for quantifying the environmental impacts of a product, process, or service across its entire life span — from raw material extraction through production, use, and end-of-life disposal. Codified in ISO 14040 and ISO 14044, and comprehensively reviewed by Finnveden et al. (2009), LCA enables decision-makers to compare alternatives, identify environmental hotspots, and support eco-design, with applications spanning products, buildings, energy systems, and public policy.
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When to use it
Use LCA when you need a comprehensive, quantitative environmental profile of a product or system across multiple impact categories and life stages. It is appropriate for eco-design comparisons, environmental product declarations (EPDs), and policy support. Key assumptions include linearity of the inventory system and choice of impact assessment methodology (e.g., ReCiPe, CML). Limitations include data-intensive requirements, sensitivity to system-boundary choices, and difficulty capturing site-specific or social impacts. Alternatives include material flow analysis for resource stocks or carbon footprinting for a single impact.
Strengths & limitations
- Holistic coverage of the entire product life span avoids burden-shifting between life stages.
- Standardized under ISO 14040/14044, ensuring methodological transparency and comparability across studies.
- Supports multi-criteria environmental analysis across a wide range of impact categories simultaneously.
- Enables quantitative comparison of design alternatives, supporting evidence-based eco-design decisions.
- Highly data-intensive; background database quality and completeness critically affect result reliability.
- System boundary and functional unit choices are subjective and can substantially alter conclusions.
- Mid-point characterization factors carry scientific uncertainty, and endpoint aggregation involves value judgments.
- Spatial and temporal variability of environmental impacts is often poorly captured by average inventory data.
Frequently asked
What is a functional unit and why does it matter?
A functional unit is a quantified description of the function delivered by the system being studied — for example, '10 000 washing cycles at 40 °C.' It provides the common reference that makes two alternatives truly comparable. Without a well-defined functional unit, you may be comparing unlike things, such as a long-life LED bulb against a short-life incandescent, without accounting for the difference in service delivered.
What is the difference between attributional and consequential LCA?
Attributional LCA describes the environmental burden allocated to a product system using average, historical data — it answers 'what is the footprint of this product as produced today?' Consequential LCA uses marginal, forward-looking data to model how the system would change if a decision is made — it answers 'what happens to total environmental impacts if we switch to this alternative?' The choice has major implications for system boundary and database selection.
How reliable are LCA results given database and modeling uncertainties?
LCA results carry meaningful uncertainty from data quality, system-boundary choices, and characterization factors. Uncertainty analysis (Monte Carlo simulation) and sensitivity analysis are recommended by ISO 14044 to quantify and communicate this uncertainty. Results are best interpreted as order-of-magnitude comparisons and directional indicators rather than precise absolute values, especially when differences between alternatives are small relative to uncertainty ranges.
Sources
- Finnveden, G., et al. (2009). Recent developments in life cycle assessment. Journal of Environmental Management, 91(1), 1–21. DOI: 10.1016/j.jenvman.2009.06.018 ↗
How to cite this page
ScholarGate. (2026, June 2). Life Cycle Assessment (LCA). ScholarGate. https://scholargate.app/en/sustainability/life-cycle-assessment
Which method?
Set this method beside its closest kin and read them side by side — the library lays the books on the table; the choice is yours.
- Ecological FootprintSustainability↔ compare
- LMDI DecompositionSustainability↔ compare
- Material Flow AnalysisSustainability↔ compare