Life Cycle Impact Assessment (LCIA)

LCIA converts Life Cycle Inventory (LCI) flows—materials, energy, water, and emissions—into quantitative environmental impact indicators. It translates tonnes of CO₂, grams of NOₓ, or cubic metres of water into understandable impact categories such as climate change, resource depletion, or water scarcity, enabling comparison and prioritisation of eco-design improvements.

Objectives of LCIA

• Understand the magnitude and relevance of potential impacts associated with a product or process.
• Identify critical hotspots where reduction actions will be most effective.
• Assess alternatives in materials, energy, or logistics under a common metric.
• Communicate results in EPDs, CSRD reports, or Digital Product Passports (DPPs).

Main Stages According to ISO 14044

1. Selection of impact categories: climate change, water scarcity (AWARE), acidification, eutrophication, toxicity, resource depletion, etc.
2. Classification: assign each inventory flow to relevant categories (CO₂ → climate change; NOₓ → acidification).
3. Characterisation: multiply each flow by a characterisation factor (GWP100, AP, EP, AWARE) and sum to obtain total contributions.
4. (Optional) Normalisation: express results relative to reference loads (e.g. annual per-capita footprint in Europe).
5. (Optional) Weighting: apply weights to aggregate categories into a single index based on political or scientific relevance.
6. Interpretation: analyse uncertainty, sensitivity, and consistency with goal and scope.

Most Widely Used LCIA Methods

• IPCC GWP100 (climate change).
• ReCiPe 2016 (18 midpoint categories plus endpoint damage indicators).
• EF 3.1 (PEF) by the European Commission for Environmental Product Declarations.
• TRACI 2.1 (US EPA).
• CML-IA Baseline (Leiden University).
• AWARE for scarcity-adjusted water footprint.
• USEtox 2.1 for human toxicity and ecotoxicity.

Characterisation Factors: CO₂ and Water Examples

• CO₂ → GWP100: 1 kg CO₂e per kg CO₂.
• CH₄ → GWP100: 27.9 kg CO₂e per kg CH₄ (AR6).
• N₂O → GWP100: 273 kg CO₂e per kg N₂O.
• Water consumption in the Segura basin: AWARE factor 23 → 1 m³ × 23 = 23 m³ water scarcity equivalent.

Compatible Tools and Software

• SimaPro, OpenLCA, GaBi, Brightway2, One Click LCA with databases such as ecoinvent, EF 3.1, Agri-footprint.
• Cloud LCA APIs: Ecochain, Earthster, GreenDelta services.
• BIM plug-ins integrating ReCiPe and ILCD for the construction sector.

Best Practices

• Method–goal consistency: use ReCiPe for general comparisons; EF 3.1 for EPDs under PEFCRs.
• Transparency: clearly state factors used and update year (IPCC AR6 vs AR5).
• Sensitivity analysis: vary key flows by ±20% to test robustness.
• External critical review for publicly disclosed studies.
• Avoid double counting between blue water use and water scarcity indicators.

Synergies with Regulations and Standards

• ESPR Regulation: requires Cradle-to-Gate LCIA and disclosure via the Digital Product Passport.
• ISO 14068: Net-Zero claims require LCIA evidence of real emission reductions.
• LEED / BREEAM: LCA credits and impact reductions versus reference scenarios.
• CSRD / ESRS E1–E5: quantified disclosure of key environmental impact categories.

Emerging Challenges

• Dynamic LCA: incorporating temporal variations in electricity mixes and climate conditions.
• Social impacts (S-LCA): integrating the social dimension with environmental LCIA.
• Data interoperability: shared ontologies, APIs, and blockchain-based exchange.
• Combined footprints: simultaneous accounting of carbon, water, and biodiversity without overlaps.

Life Cycle Impact Assessment translates raw inventory data into actionable indicators for decision-making. Selecting appropriate methods, maintaining transparency, and addressing uncertainty are essential pillars of a robust LCIA that supports sustainable innovation and regulatory compliance.