Page 115 - Materials Chemistry, Second Edition

LIFE CYCLE IMPACT ASSESSMENT 97

(ii) Methods addressing the scarcity of the resource by basing the
assessment on the ratio between what is currently extracted
related to some measure of available (EDIP) resources or
reserves (CML); and
(iii) Methods based on environmental impacts from future extrac-
tions results in the need for additional efforts which can be trans-
lated into higher energy or costs, and thus leads to an increased
impact on the environment and economy (Müller-Wenk, 1998;
Steen, 2006).

Methods of this latter category are typically implemented in Eco-indicator 99,
EPS, LIME, and IMPACT 2002+. The scopes of these approaches are so diverse
that choosing one or the other might lead to completely different results and
conclusions. Moreover, LCA practitioners and decisions makers are often not
aware of what exactly these indicators represent and their underlying assump-
tions/limitations. For example category (i) methods, although being relatively
robust, are of little environmental relevance in expressing resource deple-
tion (EC-JRC 2010). Category (ii) methods express the rate of disappearance
of a given resource. When summing up these rates among different resource
extractions over the life cycle of a product to calculate the impact score of this
impact category, one implies the assumption that each resource is interchange-
able (i.e. one can replace another). Although this may be true in some cases, it
is doubtful this is always the case. For example, applying this implicit weight-
ing makes the assumption that the depletion of 1kg of mineral x can be solved
by using 1kg of mineral y with a lower disappearance rate independent of its
functionality. Finally, several authors suggest that it is debatable to consider
category (iii) methods based on environmental impacts from future extractions
being part of the impact assessment, but should be included in the inventory
analysis (Weidema, Finnveden et ah 2005; Finnveden, Hauschild et al 2009).
No method has yet been able to follow the recommendations to move to
a functionality-driven assessment framework as suggested by some research-
ers (Jolliet, Müller-Wenk et al 2004; Margni, Gloria et al 2008). In such a frame-
work, resources are considered to have only a functional value to humans and
ecosystems, but no intrinsic value (i.e. a value for the sake of its existence as is
the case for humans and ecosystems). This means that resource consumption
has an impact only when its functionalities to humans and the ecosystems are
degraded or lost.

4.7.4 Integrating Water Use and Consumption in LCIA

The emergence of such of a framework based on resource functionality dis-
sipation and degradation that accounts for competition between the users
of a given resource and eventually their adaptation capacity has, however,
been observed by several researchers performing work in the context of the
assessing water use, and more particularly by the framework developed by