Earthster provides life cycle impact assessment (LCIA) results that are transparent, methodologically sound, and consistent with established reference implementations.

For most impact assessment methods, LCIA results calculated from ecoinvent 3.12 life cycle inventories in Earthster are closely aligned with results obtained directly from ecoinvent via ecoQuery (check tables 1 and 2 below).

Where differences occur, they are systematic and explainable. They arise from a limited number of well‑understood causes, including:

This page documents these differences in detail to ensure full transparency and reproducibility.

This section presents a systematic comparison of life cycle impact assessment (LCIA) results calculated in Earthster against the corresponding results provided by ecoinvent ecoQuery, using identical ecoinvent 3.12 life cycle inventories.

In this context, a benchmark refers to a one-to-one comparison of LCIA results produced by Earthster and ecoQuery:

Differences therefore reflect LCIA implementation choices only (e.g. characterization factors, context mapping, proxy selection), and not differences in inventory data.

For each impact category, differences are summarized statistically (mean, median, and maximum), allowing both typical and extreme deviations to be identified.

The benchmark results fall into two broad groups:

These groups are presented separately below.

Table 1 summarizes all impact categories for which no differences in impact results occur between Earthster and ecoQuery across any of the 26,533 ecoinvent datasets.

These categories demonstrate full alignment between Earthster’s LCIA implementation and ecoinvent ecoQuery.

Table 1. Impact categories with identical results across all ecoinvent datasets

Not all impact categories were included in the benchmark comparison. Exclusions were applied deliberately to avoid misleading or redundant comparisons and are explained below.

Endpoint categories (e.g. ReCiPe 2016 Endpoint H/I/E) were excluded because they are aggregations of midpoint categories. Their benchmark behavior therefore directly reflects that of their underlying midpoints and does not provide additional insight.

An exception was made for ImpactWorld+ endpoint categories. Because ecoinvent does not provide benchmarks for most ImpactWorld+ midpoint categories, two endpoints were benchmarked as proxies for the non-benchmarked midpoints.

All water consumption–type categories were excluded from the benchmarks. ecoinvent applies an overridden methodology for these categories that differs fundamentally from standard LCIA implementations, making direct numerical comparison with Earthster methodologically inconsistent and not meaningful.

The category ReCiPe 2016 – Resource use, fossils was excluded due to an issue in ecoinvent’s implementation, where characterization factors intended for Cesium are also attributed to Cerium. This misattribution leads to substantially inflated impacts for Cerium-related models—sometimes approaching an order of magnitude difference relative to results obtained in Earthster.

Including this category would distort the benchmark comparison and was therefore avoided.

Four ecoinvent datasets were excluded because ecoQuery results exhibit floating-point numerical imprecision, leading to non-zero impacts where no impacts should occur. These datasets were excluded to prevent spurious benchmark deviations.

Impact methods or categories not provided through ecoinvent ecoQuery were also excluded, including:

Since EN15804+A2 and ECI are based on EF 3.1, their numerical behavior and reasons for divergence closely mirror those observed for EF 3.1 categories and are documented accordingly.

The impact categories listed below show systematic differences between Earthster and ecoinvent ecoQuery LCIA results across the benchmarked datasets.

To improve readability, the information is split into two tables:

Impact methods ReCiPe and TRACI leave ambiguities in how characterization factors should be assigned to specific emission contexts.

For example:

Because of these gaps, different databases and software systems apply different mapping rules.

Earthster follows the context mapping curated by FEDEFL, which aims to be conservative and method‑consistent.

In total, 251 substances are affected by these context mapping differences.

Many inventory substances do not appear explicitly in LCIA methods. Both Earthster and ecoinvent address this gap using proxy mapping, but the approaches differ in scope and resolution.

Many inventory substances do not appear explicitly in LCIA methods. Both Earthster and ecoinvent address this gap using proxy mapping, but the approaches differ in coverage and specificity.

This means that, while both systems use proxies when necessary, Earthster reduces gaps in characterization factors and more consistently reflects the chemical or functional role of inventory substances. This can lead to differences in calculated impacts where ecoinvent’s CFs are incomplete.

In cases where both Earthster and ecoinvent apply proxies, Earthster selects proxies that are more chemically or functionally specific, rather than broader or more generic matches.

For example, ecoinvent may map a substance to a generic category such as “herbicides”, while Earthster maps the same substance to a specific herbicide that better reflects its chemical behavior or functional role. This approach reduces potential distortion in impact results and provides a more accurate representation of the inventory substance.

In some cases, when the LCIA method provides characterization factors for the exact substance, Earthster uses them directly, whereas ecoinvent assigns the values of a broader proxy.

This distinction explains part of the systematic differences observed between Earthster and ecoinvent in certain toxicity- and resource-use–related categories.

In several LCIA implementations, ecoinvent includes characterization factors that cannot be traced back to official impact method documentation. Their methodological origin is unclear.

Examples in TRACI – Freshwater ecotoxicity which have characterization factors but those do not appear in the original method:

Earthster excludes such factors unless they can be clearly linked to official method sources.

Additional discrepancies arise from inconsistent CF attribution in ecoinvent, including:

Earthster applies CFs strictly according to method specifications.

In some cases, ecoinvent does not assign characterization factors (CFs) to substances that are explicitly included in the LCIA method. These omissions can occur even though the method provides CFs for the substance in principle.

Earthster addresses these gaps by assigning CFs wherever the LCIA method documentation allows a defensible match, ensuring that substances present in the method contribute appropriately to the impact assessment.

This approach reduces underestimation of impacts for affected substances and ensures greater consistency with the LCIA method specifications.

As a result, certain datasets may show higher impacts in Earthster than in ecoinvent. This approach aligns with best practices across LCIA methods and provides a more complete and methodologically consistent assessment.

Some impact methods contain duplicate or synonymous substances with different characterization factors. These inconsistencies originate in the methods themselves.

Depending on which synonym is matched, Earthster and ecoinvent may produce different results.

Examples include:

Differences in assumed energy content for uranium lead to systematic differences in energy-related impact categories, including:

The divergence arises from the assumed usable energy content per kilogram of uranium.

The FEDEFL value is consistent with figures reported by the World Nuclear Association and reflects a generic, globally applicable assumption.

Interpretation

The true energy content of uranium is not a fixed physical constant. It depends on several factors, including:

ecoinvent’s higher value is derived from efficiency assumptions representative of specific national reactor fleets (notably Germany). While valid for those contexts, this assumption may not be representative of global average conditions.

Earthster applies the FEDEFL assumption to avoid embedding country-specific reactor efficiencies into globally scoped LCIA results. This choice explains the approximately 12% lower impacts associated with uranium use compared to ecoinvent.

Earthster currently retains the FEDEFL assumption, while acknowledging the inherent uncertainty in uranium energy conversion and the legitimacy of alternative values.

Ecoinvent 3.12 introduces minor modifications to a small number of characterization factors in the IPCC 2016 and EF methods. These differences originate from inconsistencies between the main IPCC report and its supplementary materials, which do not always report identical values.

The resulting impact differences are generally very small (typically below 3%, and limited to a small number of exchanges).

Earthster applies the original characterization factors as documented in the main IPCC 2016 report and does not adopt these minor adjustments. Given their limited magnitude and unclear methodological justification, Earthster will retain the original values until future method revisions (e.g. EF 3.1) explicitly resolve these discrepancies.

ReCiPe distinguishes between Methane (34 kg CO₂-eq.) and Fossil methane (36 kg CO₂-eq.), but does not explicitly define a characterization factor for Methane, land use.

In Earthster, Methane, land use is treated as Fossil methane, consistent with the approach used in IPCC, EF, and ImpactWorld+. This reflects the assumption that land-use methane emissions originate from long-term carbon stocks in soils.

In ecoinvent, Methane, land use is instead mapped to Methane (biogenic). This difference in proxy selection leads to a small discrepancy of approximately 5% in calculated climate change impacts for land-use methane emissions, with Earthster reporting slightly higher impacts.

Earthster considers alignment with other major LCIA frameworks to be a more consistent and transparent choice than ecoinvent’s proxy mapping in this case.

ecoinvent’s implementation of ImpactWorld+ includes fisheries impacts as part of the Ecosystem quality damage endpoint. Earthster does not currently include this component, leading to slight differences in endpoint aggregation.

Similarly, ecoinvent accounts for thermally polluted water in Ecosystem quality damage. This component is not included in Earthster’s current implementation.

Differences between Earthster and ecoinvent LCIA results are limited in scope, well understood, and fully documented. They primarily reflect:

Where possible, Earthster follows official method documentation and applies conservative assumptions to avoid systematic underestimation of impacts.