Page 273 - Materials Chemistry, Second Edition

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resource. For the context of LCA, Udo de Haes et al. (1999) thus define natural
resources as: “… those elements that are extracted for human use. They comprise
both abiotic resources, such as fossil fuels and mineral ores, and biotic resources,
such as wood and fish. They have predominantly a functional value for society.”
Although water and land are also resources, their use causes direct impacts on
the environment. In this respect they differ from the other resources and they are
therefore treated as individual impact categories and described in separate sections.
Currently, the resource use impact category covers mostly fossil fuels, minerals and
metals so this will also be the focus here.
In terms of future availability of a resource the issue is not the current extraction
and use of the resource per se but the depletion or dissipation of the resource.
Similar to the use of land, the use of resources can be viewed from an occupation
perspective and a transformation perspective. While a resource is used for one
purpose it is not available for other purposes, and there is thus a competition
situation. When resources are used in a way that caters to their easy reuse at the end
of the product life, they are still occupied and not immediately available to other
use, but they are in principle available to future use for other purposes. This is the
case for many uses of metals today. The occupation perspective is normally not
addressed in LCIA of resources today [with the exception of Schneider et al.
(2011)]. Rather than resource use the focus of the impact assessment is usually on
the resource loss that occurs throughout the life cycle.
Resource loss occurs through transformation of the resource when the use is
either consumptive or dispersive. Consumptive resource use converts the resource
in a way so that it no longer serves as the resource it was. An example is the use of
fossil resources as fuels, converting them in the combustion process into CO 2 and
water. The transformation occurring in dispersive resource use does not lose the
resource but uses it in a way that leads to its dispersal in the technosphere or
ecosphere in forms that are less accessible to human use than the original resource
was. Dispersive use occurs for most of the metals.
There is still much debate about what the issue of concern of natural resources is
and about how this should be addressed in LCIA (Hauschild et al. 2013). This may
be explained by the difference in functional values of natural resources on the one
hand, and intrinsic or existence values of other impact categories, assessing impacts
on human health and ecosystem quality, on the other hand. Steen (2006) sum-
marised different perceptions of the problem with abiotic resources in LCIA as: “…
(1) assuming that mining cost will be a limiting factor, (2) assuming that collecting
metals or other substances from low-grade sources is mainly an issue of energy,
(3) assuming that scarcity is a major threat and (4) assuming that environmental
impacts from mining and processing of mineral resources are the main problem.”
The extraction of resources and their conversion into materials that are used in
product systems are accompanied by energy use and direct emissions that make the
raw material extraction sector an important contributor to environmental impacts
and damages in many parts of the world. These impacts are addressed by the other
impact categories which are considered in LCA, and hence not treated under the
resource depletion impact category.