The main problem involved in valuing resource depletion is that the effect or damage occurs in the future and therefore our assessment depends on our assumptions on how this future looks like.
Resource depletion may not in itself be a problem if there is adequate time for humanity to develop technologies to deal with an imminent depletion, i.e.:
The problem is that these technologies may not be developed in time to avoid damage during the transition period.
Weidema distinguishes resource use from resource depletion by asking whether present activity reduces the quality or future usefulness of a resource. The poster separates three possible future effects: greater energy needs to extract lower-grade mineral resources, reduced opportunities associated with loss of genetic resources and biodiversity, and limits on future human consumption when essential resources become scarce.
This distinction also clarifies the boundary between life cycle inventory analysis and impact assessment. Where future processes such as recycling, restoration or resource management are planned or can reasonably be anticipated, the poster argues that they belong in the inventory. Any remaining damage to the environment or human welfare can then be considered in impact assessment. If it is uncertain whether those future activities will occur, alternative scenarios may be needed to show how the boundary choice affects the result.
For mineral stocks, the poster discusses declining ore quality and the resulting increase in extraction energy as a future process that may be modelled in the inventory. For land, it identifies loss of productive capacity as a potential depletion effect, while noting that restoration may be possible in some cases. The proposed impact focus is therefore narrowed to biodiversity and arable land rather than treating all resource consumption as an impact in itself.
These conclusions are conditional on assumptions about future technologies, population, land productivity and whether restoration measures will be implemented. The poster presents a conceptual approach and scenario-based reasoning; its long-range estimates should be read in the context of the data and expectations available in 2000, not as current forecasts.
