Annex A. IDA alternative with DMI

As an alternative to DMC, we measure the materials use with DMI (Domestic Materials Input). DMC is equal to domestic extraction plus imports minus exports, whereas DMI is equal to extraction plus imports. The idea behind measuring with DMI is that there is a more direct link with production with the use (input) of materials in this production. Also because of this direct link, it might be more appropriate to measure economic activity by (gross) production value rather than GDP. In the main text, we utilize the DMC indicator and GDP in the IDA.

However, data in the MFA do not distinguish re-export flows in the import and export data. By estimating DMC, the re-exports are cancelled out, though we do not know the exact size of these re-exports in the total of import or export. DMC is also more easily compared between countries as it accounts for exports and there is no double counting of material flows. By applying DMI, we actually take into account amounts of imports which will be re-exported and not used domestically. Re-exports do not become part of the domestic production process but are goods that enter and leave the Netherlands without hardly any processing. This gives a bias in interpreting the results based on DMI for the Netherlands. For instance, transport and storage of resources by refineries in the port of Rotterdam are partially re-exports.

With these caveats in mind, we observe the following. The DMI data show that primary abiotic resource input actually increased between 1996 and 2022 (see Figure A.1). This is in contrast to the decrease when resource use is measured with DMC (Figure 3.1 in the main text). This might partially be a data issue as DMI includes imports that will be re-exported abroad, and not used in domestic production. DMC omits such re-exports. Whether the increase also partially represents a real development, e.g. increased imports due to shift of manufacturing industries to abroad, is not clear beforehand.

Recycling data remain the same in this alternative application. Finally, we apply gross production value from the National Accounts. Gross production increased from 987 billion euro in 1996 (in constant prices of 2021) to 1823 billion euro in 2022, increasing with 85 percent in 26 years.

The IDA results with DMI and production are displayed in Figures A.2 to A.5, similar to Figures 4.1 to 4.4 in the main text. They seem to tell a similar story, though there are differences. Primary abiotic resource input (DMI) increases, whereas the resource consumption (DMC) decreased. Particularly before 2009 the DMI increased strongly (Figures A.4 and A.5).

The relative roles of the drivers are more pronounced with DMI than in the DMC variant. With DMI and production, we see the relative contributions of production growth and changes in resource efficiency are larger than in the results based on DMC and GDP, and the role of substitution and recycling smaller. Particularly the relative contribution of recycling is nearly absent (or underrated) in the whole period, following from the fact that the recycling amounts are the same as in the DMC analysis but material amounts are much larger in the DMI measure.