Exiobase 3.9.6: Methodology

Because EXIOBASE and Earthster utilize different naming taxonomies for environmental exchanges, we employ a specific mapping strategy to bridge the two systems. For the majority of substances, mapping occurs automatically when the chemical identity is identical. This is achieved through string matching supported by synonym reconciliation, such as mapping EXIOBASE’s CO2 to Earthster’s Carbon dioxide or CH4 to Methane. Where automated mapping is not possible, we apply the general assumptions described in the following sections.

By default, all Carbon dioxide, Methane, and Carbon monoxide exchanges in EXIOBASE are assumed to be of fossil origin. The following exceptions were mapped to biogenic or land-use contexts:

EXIOBASE reports Perfluorocarbons (PFC) and Hydrofluorocarbons (HFC) directly in CO2-equivalent units rather than mass units. Because GWP characterization factors vary by impact method, there is no single "correct" way to back-calculate the original mass for these generic categories.

To ensure Earthster results follow the EXIOBASE benchmarks as closely as possible, these flows are mapped directly to Carbon dioxide. While not chemically precise, this preserves the intended global warming impact assigned by the EXIOBASE team.

All EXIOBASE land-use flows represent land occupation (measured in area*time). These were mapped to the Land use flowable in Earthster, with the corresponding terrestrial contexts:

In previous versions (e.g., EXIOBASE 3.8.2), fossil fuel extraction was reported as a single aggregate flow: Domestic extraction used - Fossil fuels - total. Because that category combined fuels with vastly different energy densities—from Lignite (14 MJ/kg) to Natural Gas (50 MJ/kg) — we previously utilized Coal, anthracite as a conservative representative proxy (32 MJ/kg).

The current version provides granular data for specific fuel types. We have updated our mappings to match these specific energy carriers. Exiobase does not have, however, instructions on how to assign energetic values to each fossil fuels, and therefore we used Earthster’s standard energy contents (HHV) for these:

EXIOBASE often groups minerals and metals into categories that cover several substances. When a direct match was not possible, we mapped the flow to the representative mineral or metal in the group:

For the following cases, we did not map the exchanges to an Earthster alternative as they cover too broad a range of possible minerals:

As for ores, we mapped to their "pure" metal equivalents using a conversion factor approach. Mapping to the pure substance and then applying a conversion factor (the concentration of the substance found in the ore) is the preferred solution when the exact concentration of a metal/mineral is known. We applied the average global ore concentration factors from EXIOBASE (available here):

All resource extraction related to fisheries, primary crops, crop residues and forestry were mapped to Biomass resource/ground.

EXIOBASE distinguishes between water Withdrawal (the total volume of water taken from a source) and water Consumption (water not returned to the same source, such as through evaporation or product incorporation). In our implementation, we map EXIOBASE Water Consumption flows to the generic Earthster flowable Water (context: resource/water). This approach aligns with the assumptions of impact methods such as ReCiPe, EF3.1, ImpactWorld+, which prioritize the net balance of water removed from a watershed rather than the gross intake. Consequently, withdrawal-only flows are left unmapped to prevent double-counting and ensure that water scarcity and consumption results are not artificially inflated—a correction that is critical given that treating withdrawals as consumption can inflate results by a factor of over 400%.

EXIOBASE contains many flows that track the movement of money or the total supply of energy carriers (e.g., "Energy Carrier Supply: Total").

Our Treatment: These are "Accounting Flows" used for economic balancing. Since they do not represent a direct physical emission or a resource being removed from nature, they are not mapped to environmental impacts.

This release marks the migration to EXIOBASE 3.9.6, which introduces a more detailed inventory of environmental exchanges. The primary improvements result from Earthster’s mapping of these new, granular flows:

Version 3.8.2_e002 corrects many issues. The improvements are as follows:

Land Use: More resolution for land exchanges: Fodder crops now mapped to human-dominated/agricultural/pasture, man made instead of the more We corrected conversion factors for land-use flows and integrated generic human-dominated/agricultural