LCIA methods reference

Written by Jonathan Balsvik, last updated October 2026

A life cycle impact assessment (LCIA) method is a published set of characterization factors. Each factor turns one elementary flow (a substance emitted to air, water or soil, or a resource taken from nature) into a contribution to an indicator such as kilograms of CO2 equivalent. An impact score is the sum of every flow in the inventory multiplied by its factor [1]. Methods differ because their developers chose different impact categories, fate and effect models, reference substances, time horizons and spatial scales, and because each method is published against a particular list of flow names. This page describes nine methods and what "implementing" one means.

EF 3.1

Publisher: the European Commission's Joint Research Centre (JRC).

Version: 3.1, July 2022; EF 3.0 dates from December 2018 [3][4]. It is the method of the Product and Organisation Environmental Footprint (PEF and OEF) under Commission Recommendation (EU) 2021/2279 [5].

Categories: 16 midpoints. Climate change (kg CO2 eq, AR6 GWP100), ozone depletion (kg CFC-11 eq), human toxicity cancer and non-cancer (CTUh), particulate matter (disease incidence), ionizing radiation (kBq U-235 eq), photochemical ozone formation (kg NMVOC eq), acidification (mol H+ eq), eutrophication terrestrial (mol N eq), freshwater (kg P eq) and marine (kg N eq), freshwater ecotoxicity (CTUe), land use (soil quality index), water use (m3 world eq deprived), resource use minerals and metals (kg Sb eq) and fossils (MJ) [5][4]. Toxicity, land, water and resources carry the lowest robustness grade (III). PEF studies must also report normalized and weighted results and a single score [5][6].

Regionalization: country factors for land use, water use and, in 36 European countries, acidification and air-related categories, plus global defaults [7].

Flow list: the EF 3.1 reference list, 93,993 flows with UUIDs in ILCD format. EF 3.1 is the only method here published against its own flow list [7][8].

License: free download; no license text was found [7]. Required for PEF and OEF studies and, via the EN 15804 package, European construction EPDs [5][9].

Limits: synonyms and duplicates in the flow list carry the same factor [4].

Implementation: other databases map the EF flow list onto their own; ecoinvent, SimaPro, openLCA and the JRC package differ for water, land, particulates and toxicity [1][46].

ReCiPe 2016

Publisher: the Dutch National Institute for Public Health and the Environment (RIVM), with Radboud University, Leiden University and PRé.

Version: v1.1 (report update 2017, factor workbook January 2018); no newer release is listed by RIVM [12].

Categories: the RIVM web page says 17 midpoints; the v1.1 report and the SimaPro manual count 18, because photochemical ozone formation is split into human health and ecosystem indicators [12][2][13]. Three endpoints: human health (DALY), ecosystem quality (species.yr) and resource scarcity (US dollars) [2].

Level: midpoint and endpoint, in three perspectives (individualist, hierarchist, egalitarian) that group value choices such as time horizon [2].

Regionalization: global averages, with a separate country-factor workbook for some categories that ecoinvent does not implement and SimaPro applies only to water, at endpoint level [1][13].

Flow list: mixed. Toxicity by CAS and name, air pollutants by generic names, land use keyed to ecoinvent flow names, in RIVM's own compartments [12].

License: free; the report allows reproduction with acknowledgement, but no data license was found [12]. Customary for general LCA and academic work.

Limits: GWP values are AR5 with climate-carbon feedback (methane 34) [12].

Implementation: ecoinvent's ReCiPe is labeled "v1.03 (SimaPro)" because it was built from a SimaPro export [1].

CML-IA

Publisher: the Institute of Environmental Sciences at Leiden University (CML).

Version: 4.8, last updated August 2016 [14][1].

Categories: 11 baseline midpoints: abiotic depletion of elements (kg Sb eq) and of fossil fuels (MJ), climate change (kg CO2 eq), ozone depletion (kg CFC-11 eq), human toxicity and three ecotoxicity categories (kg 1,4-DCB eq), photochemical oxidant formation (kg ethylene eq), acidification (kg SO2 eq) and eutrophication (kg PO4 eq) [14][15]. Midpoint only, with normalization and no weighting; no regionalization [15][14].

Flow list: substance name plus CAS with main compartments only; no sub-compartments [14].

License: "can be downloaded free of charge"; no explicit license [14]. Customary in EPDs under EN 15804+A1, and its abiotic depletion model survives in EN 15804+A2 [16][5].

Limits: GWP values are AR5 (methane 28) and the method has not changed since 2016 [14][27].

Implementation: ecoinvent and SimaPro each add their own rules [1][15].

TRACI 2.1 and 2.2

Publisher: the US Environmental Protection Agency (EPA).

Version: 2.2, workbook dated 2 March 2022, posted January 2024; the user manual is for 2.1 (2012) [17][18].

Categories: TRACI 2.1 has ten: ozone depletion (kg CFC-11 eq), global warming (kg CO2 eq), smog (kg O3 eq), acidification (kg SO2 eq), eutrophication (kg N eq), particulate matter (kg PM2.5 eq), cancer and non-cancer (CTUh), ecotoxicity (CTUe) and fossil fuel depletion [18]. TRACI 2.2 removed fossil fuels and replaced eutrophication with freshwater (kg P eq) and marine (kg N eq) factors resolved by country and US state [17][19][20]. Midpoint, developed by the EPA "specifically for the US" [20].

Flow list: CAS plus upper-case names with compartments in column headers.

License: public domain under US law [21]. Customary for North American EPDs: ISO 21930 requires five categories, and EPA's factors for them "are identical to those currently in TRACI v2.1" except GHGs, which use AR5 [22][23].

Limits: the 2.2 workbook keeps AR4-era GWPs (methane 25) [17].

Implementation: ecoinvent ships only 2.1 and does not map energy resources; SimaPro and openLCA ship 2.2 [1][20].

IPCC 2021 GWP

Publisher: the Intergovernmental Panel on Climate Change (IPCC), Sixth Assessment Report (AR6), Working Group I chapter 7.

"IPCC 2021" in software means the metrics in Table 7.15 and supplementary Table 7.SM.7 [24].

Categories: one, climate change in kg CO2 eq, for GWP20, GWP100, GWP500 and GTP100. Table 7.15 gives GWP100 of 29.8 for fossil methane, 27.0 for non-fossil methane and 273 for nitrous oxide [24]. Midpoint; no regionalization.

Flow list: species names for air only, with no compartments and no biogenic carbon convention, so every implementer adds its own carbon rules [24].

License: free report; IPCC copyright applies (the copyright page could not be fetched for this review) [25]. The GHG Protocol recommends the latest (AR6) 100-year values [26].

Limits: the printed 7.SM.7 has known errors for CFC-11 and CFC-12 [25].

Implementation: vendors ship several variants. The EF 3.1 workbook and ecoinvent 3.12 disagree on some gases, for example SF6 at 25,200 against 24,300 [7][1].

EN 15804+A2

Publisher: the European Committee for Standardization (CEN), technical committee 350.

Version: EN 15804:2012+A2:2019; approved 21 July 2019, mandatory for new construction EPDs from October 2022 [16]. This page relies on the JRC package and program rules, not the paid standard text.

Categories: 13 core and 6 additional. Core: the four climate change sub-indicators, ozone depletion, acidification, three eutrophication categories, photochemical ozone formation, abiotic depletion of minerals and metals and of fossil resources, and water use. Additional: particulate matter, ionizing radiation, freshwater ecotoxicity, human toxicity cancer and non-cancer, and land use [16][27]. Midpoint, no weighting; regionalized as EF, though EPD tools generally use global factors.

Flow list: the EF flow list, following a 2016 Commission mandate to align EN 15804 with the EF method. JRC publishes an "EN 15804 reference package" based on EF 3.1 (moved from EF 3.0 in February 2023) [9][28][29].

License: the standard costs money; the JRC package is freely downloadable [28]. Required for European construction EPDs: ECO Platform requires the latest JRC factors with a one-year transition, and EPD International states "CFs based on EF 3.1 shall be used" [23][29].

Differences from EF: biogenic CO2 counts +1 on emission and -1 on uptake, and the resource indicators keep the CML model. EF 3.0 toxicity results may not be carried into an EF 3.1 EPD [27][23][16].

Implementation: ecoinvent restricts these methods to its EN15804 system model; SimaPro's version inherits its EF 3.1 adaptations [1][27].

USEtox

Publisher: the USEtox team, formed under the UNEP/SETAC Life Cycle Initiative as a consensus model.

Version: 2.14 (20 August 2024); version 3.0 exists only as a beta whose factors are "for demonstration purposes only" [30][31][32].

Categories: human toxicity cancer and non-cancer (CTUh, cases per kg) and freshwater ecotoxicity (CTUe, PAF.m3.day per kg). Metals and dissociating substances carry "interim" factors [33]. Midpoint, with endpoint factors also provided; a global default with a nested continental scale [33][18].

Flow list: CAS-keyed substance databases in USEtox's own eight emission compartments [33].

License: free download; the license page could not be fetched, so terms are not stated here. "USEtox" is a registered trademark [30]. Recommended for toxicity in PEF, used in modified form in EF 3.1, and the basis of TRACI's toxicity categories [34][5][18].

Limits: high uncertainty for metals and inorganics [4][33].

Implementation: ecoinvent carries 2.13 and SimaPro 2.12, each with its own compartment mapping and metal rules [1][33].

AWARE

Publisher: the WULCA working group of the UNEP/SETAC Life Cycle Initiative.

Versions: 1.2 (bug fix June 2024) and 2.0 (April 2025) [35][36].

Categories: one, water scarcity in m3 world eq. Factors range from 0.1 to 100, with 1 as the world average; defaults for unknown location are 43 (unspecified), 20 (non-agricultural) and 46 (agricultural) [37]. Midpoint.

Regionalization: sub-watershed and month natively, aggregated to country and year, with agricultural and non-agricultural variants; AWARE 2.0 adds subnational tables and a single hydrological model [35][36].

Flow list: none as such. Factors apply to cubic meters of water consumed, by location [37].

License: AWARE 2.0 is CC BY 4.0 on Zenodo; none was found for 1.2 [36]. WULCA lists PEF/OEF and EPD International as recommending it, and it is the EF water use model [37][5].

Limits: results depend on knowing where and when water was consumed [38].

Implementation: EF uses country factors; ecoinvent applies only the global factor to evaporated water; SimaPro carries AWARE 2.0 country averages [7][1][38].

Ecological Scarcity 2021

Publisher: the Swiss Federal Office for the Environment (FOEN, German BAFU).

"Swiss Eco-Factors 2021", published 23 December 2021, succeeding the 2013 edition; FOEN updates the method about every 7 to 10 years [39][40].

Categories: 20, all in eco-points (UBP) so results can be summed, covering resources, land use, global warming, ozone depletion, air and water pollutants, heavy metals, pesticides, radioactivity, noise and waste; 2021 added plastics and marine fish [41][15]. Single score: each eco-factor combines characterization, normalization and distance-to-target weighting against Swiss policy targets [15][41].

Regionalization: country water factors (AWARE times 23 UBP per m3) and country and ecoregion land use [39][41].

Flow list: report tables by substance, CAS and compartment, aimed at the Swiss federal LCI data. ecoinvent received the factor file by e-mail and notes it may differ from the report [41].

License: free report; no data license beyond FOEN copyright was found [39]. FOEN calls it the reference method for Swiss LCAs [40]. The KBOB/ecobau construction data list, version 9.0, underpins the SIA standards 2032, 2039 and 390/1 [42].

Limits: weighting reflects Swiss policy targets [15], so the single score cannot be compared with single scores from other methods.

Implementation: ecoinvent adds factors for about 40 elements and global land factors the method lacks; SimaPro ships two variants, one "aligned with BAFU" [41][15].

A note on ReCiPe endpoints

ReCiPe's endpoints aggregate the midpoints into three damage categories: human health in disability-adjusted life years, ecosystem quality in species.yr and resource scarcity in dollars of surplus cost. Weighting across the three is a value choice. RIVM states that midpoint characterization "has a stronger relation to the environmental flows and a relatively low uncertainty, while the endpoint characterisation provides better information on the environmental relevance of the environmental flows, but is also more uncertain" [2]. The three perspectives alone shift climate change damage to ecosystems from 1.5E-14 to 6.8E-13 species.yr per kg CO2 [2]. Report the midpoints alongside any endpoint.

Coming methods

GLAM

The UNEP Life Cycle Initiative launched the Global LCIA Method (GLAM 1.0.2024.10) in October 2024, reporting about one million factors for 14,000 flows across 22 impact categories and three areas of protection [43]. Beta releases 1.1 (latest June 2026) are on Zenodo under CC BY 4.0, matched to the EF 3.1 substances and compartments, and marked "not intended to be cited" [44]. No ecoinvent, SimaPro or openLCA implementation was confirmed.

EF 4.0

The Commission projects EF 4.0 for 2028 and describes it as under development; interim guidance covers 2025 to 2028 [10][11]. A 2025 JRC report says the EF method "is under revision and is considering the inclusion of novel methods for the assessment of microplastic release and biodiversity impacts" [45]. No list of category, factor or flow-list changes has been published.

AWARE 2.0 is published and in SimaPro; EF 3.1 still uses the older AWARE factors [36][38].

Comparison table

How to choose

Which method does my program require?

PEF and OEF: EF 3.1 with all 16 categories, normalization and weighting [5]. European construction EPD: the JRC EN 15804 package, currently EF 3.1 based [23][29]. North American EPD: ISO 21930 categories with TRACI factors [22]. Swiss buildings: the KBOB/ecobau list behind the SIA standards [42]; Swiss LCAs generally: Ecological Scarcity 2021 [40]. Corporate GHG inventory: AR6 GWP100 [26].

Do I need endpoint results?

Only ReCiPe offers endpoints, and Ecological Scarcity offers a single score. Show the midpoints alongside either [2].

Does my software carry the official implementation or an adapted one?

SimaPro states that its "EF 3.1 (adapted)" method "is not suitable for conducting EF-compliant studies" and ships the unmodified method separately; ecoinvent states that its implementation "may differ from implementations provided by LCA software" [46][1].

Are my results comparable with a study that used another version?

Not without checking. EF 3.0 to 3.1 changed climate change, acidification, ozone formation and all toxicity categories [4]. TRACI 2.1 to 2.2 changed eutrophication and dropped fossil fuels [17][20].

Are the categories I care about regionalized in my tool?

ecoinvent applies global factors only and warns that "implementation of global CFs can affect results a lot" for land and water [1].

What flow list is my inventory on?

Mapping a method to another flow list loses unmatched flows and adds proxy factors. Ask the vendor for the mapping file and its version [27].

FAQ

What is the difference between a midpoint and an endpoint method?

A midpoint factor stops part way along the cause-effect chain, for example at kg SO2 eq. An endpoint factor continues to damage, such as species lost. Endpoints are easier to communicate and harder to defend [2].

Why do EF 3.1 results differ between ecoinvent, SimaPro and openLCA?

Each vendor maps the JRC factors onto its own flow list and makes its own choices about water accounting, particulate classes, heating values and regional factors. Climate change usually agrees; water, land, particulates and toxicity often do not [46][1].

Is EN 15804+A2 the same as EF 3.1?

Nearly. It uses the EF flow list and factors, but biogenic CO2 is +1 on emission and -1 on uptake instead of 0, and the resource indicators keep the CML model [27][16].

Which GWP values should I use?

For PEF and EN 15804 EPDs, the values inside EF 3.1, which are AR6 based. For GHG Protocol reporting, the latest IPCC 100-year values. CML-IA, ReCiPe 2016 and TRACI still carry AR4 or AR5 values [12][14][17].

Can I redistribute these factor tables in my own tool?

TRACI is public domain; AWARE 2.0 and GLAM are CC BY 4.0. ReCiPe, CML-IA, EF, USEtox and Ecological Scarcity are free to download, but no explicit data license was found on their download pages [21][36][44][12][14][7][30][39].

How do I record which implementation I used?

Note the method name and version, the implementing vendor and its release (for example "EF 3.1, ecoinvent 3.12 mapped, corrected"), the flow list of the inventory and the date.

Related reference

• LCI databases compared: the main inventory databases, their flow lists and licenses, and what must match before combining them.
• LCIA method selection: how to choose between ReCiPe, CML, TRACI and EF 3.1 for a study.
• LCA glossary: definitions of the terms used on this page.

Sources

1. ecoinvent, Implementation of Life Cycle Impact Assessment Methods in the ecoinvent Database v3.12 (2025), sections 2, 6.5, 6.6, 8, 14, 15.3, 16.3, 19, 20 and 21: https://support.ecoinvent.org/hubfs/Knowledge%20Base/Database/Releases/3.12/LCIA%20Implementation%20v3.12.pdf
2. RIVM, ReCiPe 2016 report 2016-0104, sections 1.1 to 1.3, Tables 1.2 and 1.4: https://www.rivm.nl/bibliotheek/rapporten/2016-0104.pdf ; v1.1 update: https://www.rivm.nl/sites/default/files/2018-11/Report%20ReCiPe_Update_20171002_0.pdf
3. JRC, Updates to the Guide for EF compliant data sets for EF 3.1 (2022): https://eplca.jrc.ec.europa.eu/permalink/EF_Data_Guide_EF3.1_addendum.pdf
4. JRC, Updated characterisation and normalisation factors for the Environmental Footprint 3.1 method (JRC130796, 2023): https://publications.jrc.ec.europa.eu/repository/bitstream/JRC130796/JRC130796_01.pdf
5. Commission Recommendation (EU) 2021/2279, Annex I, Table 2 and section 5: https://eur-lex.europa.eu/legal-content/EN/TXT/PDF/?uri=CELEX:32021H2279 ; http://data.europa.eu/eli/reco/2021/2279/oj
6. JRC, EF 3.1 normalisation and weighting factors: https://eplca.jrc.ec.europa.eu/permalink/EF3_1/Normalisation_Weighting_Factors_EF_3.1.xlsx
7. JRC EF 3.1 characterisation factor workbook: https://eplca.jrc.ec.europa.eu/permalink/EF3_1/EF-LCIAMethod_CF(EF-v3.1).xlsx
8. European Commission, EF reference package 3.1: https://knowledge-for-policy.ec.europa.eu/european-platform-life-cycle-assessment-eplca/life-cycle-data-network-lcdn/reference-package_en
9. European Commission, EF LCIA method for EN 15804: https://knowledge-for-policy.ec.europa.eu/european-platform-life-cycle-assessment-eplca/topic/ef-lcia-method-en-15804_en
10. European Commission, Data for EF methods (EF 4.0 projected for 2028): https://green-forum.ec.europa.eu/green-business/environmental-footprint-methods/data-ef-methods_en
11. European Commission, Guidance on the implementation of Recommendation 2021/2279 in the context of lower availability of EF-compliant datasets (April 2026): https://op.europa.eu/en/publication-detail/-/publication/8fe38f0b-4829-11f1-8095-01aa75ed71a1/language-en
12. RIVM, ReCiPe page and downloads: https://www.rivm.nl/en/life-cycle-assessment-lca/recipe ; https://www.rivm.nl/en/life-cycle-assessment-lca/downloads
13. PRé Sustainability, SimaPro database manual, Methods library (March 2026 edition), section 5.3: https://simapro.com/wp-content/uploads/2026/04/DatabaseManualMethods.pdf
14. Leiden University, CML-IA characterisation factors: https://www.universiteitleiden.nl/en/research/research-output/science/cml-ia-characterisation-factors
15. PRé Sustainability, SimaPro database manual, sections 4.1 (CML-IA), 4.2 and 4.3 (Ecological Scarcity 2021): as in 13
16. One Click LCA, EN 15804+A2: what the changes mean for EPDs: https://oneclicklca.com/en/resources/articles/en-15804-changes-epds
17. US EPA, TRACI page and TRACI 2.2 workbook: https://www.epa.gov/chemical-research/tool-reduction-and-assessment-chemicals-and-other-environmental-impacts-traci ; https://www.epa.gov/system/files/documents/2024-01/traci_2_2.xlsx
18. US EPA, TRACI 2.1 User's Manual (EPA/600/R-12/554, 2012), Table 1 and Impact Category Headings: https://cfpub.epa.gov/si/si_public_record_report.cfm?LAB=NRMRL&dirEntryID=274755
19. Federal LCA Commons, TRACI 2.2 released: https://www.lcacommons.gov/traci-22-life-cycle-impact-assessment-method-released
20. PRé Sustainability, SimaPro database manual, section 6.2 (TRACI 2.2): as in 13 ; GreenDelta, TRACI 2.2 in openLCA (2024): https://nexus.openlca.org/ws/files/36003
21. US EPA, Standard Open Data License: https://edg.epa.gov/epa_data_license.html
22. US EPA, Characterization Factors for Construction Material EPD Indicators (ISO21930-LCIA-US) v0.1 (2024): https://catalog.data.gov/dataset/characterization-factors-for-construction-material-epd-indicators-iso21930-lcia-us-v0-1
23. ECO Platform, LCA Calculation Rules V2.0 (December 2024), sections 2.9 and 2.13: https://www.eco-platform.org/files/download/Documents/2025/LCA%20Calculation%20Rules%20V2.0.pdf
24. IPCC AR6 WGI, Chapter 7 (Forster et al., 2021), Table 7.15: https://www.ipcc.ch/report/ar6/wg1/downloads/report/IPCC_AR6_WGI_Chapter07.pdf
25. IPCC WGI chapter 7 authors' metrics file and notes on 7.SM.7 errors: https://github.com/IPCC-WG1/Chapter-7
26. GHG Protocol, Global Warming Potential Values v2.0 (August 2024): https://ghgprotocol.org/sites/default/files/2024-08/Global-Warming-Potential-Values%20(August%202024).pdf
27. ecoinvent, EN15804+A2 core and additional mapped files (3.12): https://github.com/ecoinvent/lcia ; PRé, SimaPro database manual, section 4.6 (EN 15804+A2 adapted, Table 2): as in 13
28. European Commission, EN 15804 reference package (EF 3.1 based): https://knowledge-for-policy.ec.europa.eu/european-platform-life-cycle-assessment-eplca/life-cycle-data-network-lcdn/en-15804-reference_en
29. EPD International, GPI 5, characterisation factors: https://www.environdec.com/services/environmental-performance-indicators/gpi-5
30. USEtox, home page (official 2.14 model and factors, trademark): https://usetox.org/
31. USEtox 2.14 release page (20 August 2024): https://usetox.org/model/download/usetox2.14
32. USEtox 3.0 beta 8a (demonstration factors only): https://usetox.org/model/download/usetox-3.0beta8a
33. PRé Sustainability, SimaPro database manual, section 7.11 (USEtox): as in 13
34. UNEP Life Cycle Initiative, The USEtox Model: https://www.lifecycleinitiative.org/applying-lca/usetox/
35. WULCA, AWARE factor downloads and version history: https://wulca-waterlca.org/what-is-aware/download-aware-factors/
36. Seitfudem, Berger, Müller Schmied, Boulay, AWARE2.0 data (Zenodo, CC BY 4.0; v1.0.0 April 2025, v1.0.2 July 2026): https://zenodo.org/records/15133241 ; https://zenodo.org/records/21708463 ; paper: https://doi.org/10.1111/jiec.70023
37. WULCA, What is AWARE: https://wulca-waterlca.org/what-is-aware/
38. PRé Sustainability, SimaPro database manual, section 8.1 (AWARE): as in 13
39. FOEN, Swiss Eco-Factors 2021 according to the Ecological Scarcity Method (23 December 2021): https://www.bafu.admin.ch/en/publications-economy-and-consumption
40. BAFU, Ökobilanzierung (UBP method updated every 7 to 10 years; reference method for Switzerland): https://www.bafu.admin.ch/de/oekobilanzierung
41. ecoinvent, Implementation of LCIA Methods v3.12, section 14 (Ecological Scarcity): as in 1
42. ecobau, Ökobilanzen (KBOB/ecobau list version 9.0, SIA standards): https://www.ecobau.ch/de/instrumente/oekobilanzen
43. UNEP Life Cycle Initiative, GLAM: https://www.lifecycleinitiative.org/activities/life-cycle-assessment-data-and-methods/global-guidance-for-life-cycle-impact-assessment-indicators-and-methods-glam/
44. GLAM 1.1.2026.06.24 beta (Zenodo, CC BY 4.0): https://zenodo.org/records/20630461
45. JRC143211 (2025), footnote on EF method revision: https://publications.jrc.ec.europa.eu/repository/bitstream/JRC143211/JRC143211_01.pdf
46. PRé Sustainability, SimaPro database manual, section 4.4 (Environmental Footprint 3.1 adapted): as in 13