Page 28 - Materials Chemistry, Second Edition

2.1 Sustainability and sustainable development: Main concepts and approaches 23
The Capital approach to Sustainable Development (Daly and Cobb, 1989; Pearce et al.,
1989; Pearce and Turner, 1990) has been developed in order to make sustainability concep-
tually closer to the business sector and raise its attention on the issue (Goodwin, 2003). Ostrom
and Ahn (2003) define capital as a set of resources that could be immediately consumed,
but are instead allocated to future wealth generation. In this case, the economic rule of
nondeclining capital, or capital maintenance (Victor, 1991), has been transposed to the
concept of sustainable development. The Handbook of National Accounting (United Nations,
2003) defines sustainable development as one that ensure a nondeclining pro capita national
wellness by replacing or conserving the sources of that wellness, that is to say different
capital typologies’ stocks. Several capital classifications exist identifying four, five, or six cap-
ital typologies considering financial, man-made, social, human, cultural, and natural capital
(Forum for the Future, n.d.; Goodland, 2002; Goodwin, 2003; Hallsmith and Lietaer, 2011;
International Integrated Reporting Council, 2013). Development is then sustainable if the
sources of wealth (man-made, social, cultural, human, financial, and natural capital) are
maintained rather than depleted or degraded in order to leave to the future generations a
capital stock able to deliver the same wellbeing current generations have access to (Pearce
and Atkinson, 1998; Forum for the Future, n.d.; Goodwin, 2003; Hallsmith and Lietaer, 2011).
An open discourse exists concerning the substitutability or complementarity between
capitals, and especially between the natural and the other forms of capital (UN et al.,
2003). On the one side, according to the weak sustainability idea, the overall capital has
to be maintained over time, while the different capital types can be substituted between them.
On the other side, the strong sustainability approach affirms capital nonsubstitutability
(Pearce and Atkinson, 1993; UN et al., 2003; Dietz and Neumayer, 2007). This derives
from the fact that different capitals are responsible for delivering different functions (Ekins
et al., 2003), and some capitals actually have value only if combined together (complementar-
ity). However, Turner (1993 as cited in Ekins et al. 2003) identifies some middle ways between
the two rules, presenting four positions. On the one side, very weak sustainability consists
in complete capital substitutability, whereas weak sustainability admits substitutability
between natural and manmade capital with minor exceptions. On the other side, Strong
sustainability affirms that substitution between natural and manmade capital could be
importantly undermined by the irreversibility of certain natural capital depletion or deteri-
oration, or by the existence of critical natural capital stocks delivering unique functions
indispensable for life. Moreover, the depletion of certain natural capital stocks could
have no impact until a given threshold, showing nonlinearity after passing it (Rockstrom
et al., 2009; Dyllick and Hockerts, 2002). Given the uncertainty consequent to an incomplete
scientific knowledge concerning nature and society-environment interactions, the precau-
tionary principle is thus supported by numerous authors and institutions (Pearce and Turner,
1990; United Nations, 1992a, b). Lastly, very strong sustainability proposes complete
nonsubstitutability between capitals but it is not taken into concrete consideration, whereas
the most likely approaches seem to be weak and strong sustainability. Fig. 2.1 represents the
different capital substitutability scenarios based on a very weak, strong, or very strong sus-
tainability approach. With a very weak sustainability approach, there is a complete substitut-
ability among different capitals (namely natural, social, cultural, human, financial, and
manmade). With a strong sustainability model the concept of critical capital stock is intro-
duced. Substitutability among different capitals can be only partially accepted until specific
thresholds of critical capital stocks. Depleting critical capital stocks can be risky in terms of