IMPACT World+
Version 2.1
A globally regionalized method for life cycle impact assessment (LCIA).
Table of Contents
New indicators
Plastic physical effect on biota
This indicator quantifies the impact of plastic resins released into aquatic environments (both freshwater and marine) on biota, expressed in PDF·m²·yr. It also includes a midpoint indicator measured in CTUe. This indicator is based on the work of the MarILCA working group.
Fisheries impact
This indicator quantifies the biodiversity impacts of fisheries activities, measured exclusively at the ecosystem quality damage level (in PDF·m²·yr). It is derived from the work of Stanford-Clark.
Marine & terrestrial ecotoxicity
These indicators quantify the ecotoxicity impacts on marine and terrestrial environments, assessed only at the damage level. They are based on an earlier version of USEtox (v2.02). As USEtox v3 is nearing release, all ecotoxicity and toxicity categories will be updated in the next version of IW+. These indicators complete the Freshwater ecotoxicity indicator that was already featured by previous versions of IMPACT World+.
Photochemical ozone formation, ecosystem quality
This indicator quantifies the impact of photochemical ozone formation, following the recommendations of the ReCiPe methodology. In their 2016 update, ReCiPe renamed this category from “Photochemical oxidant formation” to “Photochemical ozone formation”. Accordingly, the two corresponding damage-level impact categories are named “Photochemical ozone formation, human health” and “Photochemical ozone formation, ecosystem quality.” While the first one already existed in the method, the second one was added in version 2.1.
Updated indicators
All climate change indicators - biogenic carbon accounting
With the v2.1 update, users have the possibility to choose between two versions of IMPACT World+ corresponding to two different philosophies when it comes to quantifying the impacts of biogenic greenhouse gases (GHGs).
The carbon neutrality approach (0/0)
The carbon neutrality approach, which has always been the default in IMPACT World+, characterizes the effect of biogenic CO2 as neutral. Hence, for GWP100, CO2 biogenic flows have a null characterization factor. Biogenic CH4 has a lower CF than the fossil one. Considering the direct differentiation of CO into CO2, biogenic CO also has a null characterization factor.
The incl. CO2 uptake approach (-1/+1)
In the (incl. CO2 uptake) files, biogenic carbon is accounted just as fossil carbon. However, the uptake of carbon is characterized with a negative CF (-1) while the release is characterized with a positive CF (+1). Other biogenic GHGs (CH4 and CO) are also accounted as fossil GHGs, with the same characterization factor.
Within the (incl. CO2 uptake) version, each impact category related to climate change was separated into four sub-categories: fossil, biogenic, land transformation, CO2 uptake. This separation is recommended by various standards such as the PEF and GHG protocol.
Climate change, human health
These CFs were updated in version 2.1 to align with the AR6 recommendations from IPCC 2021, as was already done for midpoint indicators in the previous version of the method. The cumulative AGTP100 and AGTP500 used in their derivation was recalculated using updated equations provided by Yue He and Thomas Gasser from the International Institute for Applied Systems Analysis (IIASA). The effect factors were also revised, replacing older data from the World Health Organization (2003) with more recent sources.
Climate change, ecosystem quality
These CFs were updated with recalculated cumulative AGTP100 and AGTP500 values, similar to the human health indicators. However, the effect factors for this category have not yet been revised.
Particulate matter formation
These CFs were updated using the latest model by Fantke et al. (developed in this article and this article) which includes updates to fate and effect factors. The model introduces regionalized CFs for towns with populations over 100,000 to calculate the regional CFs that are used for the indicator. All national/regional (e.g., RER) and global CFs recalculated from town-level data are included in the development files and software versions.
Water availability, human health
These CFs were updated with the latest model from Debarre (2024), harmonizing methodologies for domestic and agricultural water use, updating exposure factors using recent Gross National Income data, and revising effect factors.
Water availability, terrestrial ecosystems
These CFs were updated with new regionalization data based on groundwater depth estimates from Jasechko (2021).
Water scarcity
These CFs were updated to incorporate the latest version of the AWARE model (AWARE2.0) developped by Seitfudem et al. (2024).
Fossil and nuclear energy use
These CFs were updated to align with the latest updates to Higher Heating Values (HHVs) in ecoinvent.
Ozone layer depletion
These CFs were updated using the latest data from the World Meteorological Organization (2022). The time horizon for this impact category was also extended indefinitely, replacing the previous 500-year limitation.
Precise report of changes
The precise reports of changes (flow by flow), for all software and database for which we provide an IW+ version, are available in the Documentation section.
Note that those reports depend on the database/software combination as software typically do not cover the same elementary flows and use different names.