92
E.C.M. Ruijgrok . P. Vellinga
Natural capital consists of all natural resources and processes humans make use of.
Produced capital is man made, e.g. machinery stock. Human capital is labour, both in
quantitative (number of workers) and qualitative (skills) terms. Social capital concerns
society's institutional arrangements.
In theory one can distinguish between three types of sustain ability on basis of the
allowed substitutions between and within the four capital stocks: strong sustainability,
moderate sustainability and weak sustainability.
Here strong sustain ability means that the welfare generating capacity of a national
total capital stock may not decrease and that the welfare potential of each of the individual capital stocks may not be diminished. In other words: natural capital may not
be replaced by produced capital and one specific type of natural capital (e.g. forests)
may not be substituted by another specific type (e.g. wetlands). Both substitution betwe~n and within capital stocks are forbidden.
Moderate sustainability will be realized if the welfare generating capacity of both
the total capital stock and of each of the individual capital stocks are not reduced.
Natural capital may not be substituted by produced capital, because the two capital
stocks are considered to be complementary. The welfare generating capacity of a specific part of an individual capital stock may however be reduced here, as long as it is
compensated for by an increase in welfare generating capacity of another part of this
stock. This means that decrease of a part of the natural capital stock (e.g. forests) may
be compensated by an increase of another part of this stock (e.g. wetlands), but not by
an increase in the produced capital stock (e.g. machinery). In other words: substitution between capital stocks is not allowed, but substitution within capital stocks is.
Weak sustainability means that the welfare generating capacity of all four capital stocks
together may not decrease, but it leaves room for substitution. If one capital stock is reduced this may be compensated by growth of another capital stock, as long as the total
welfare generating capacity is not reduced. Now it becomes possible to substitute
e.g. natural capital with produced capital. It is also allowed to have growth or shrink within
one capital stock; a reduction in unskilled labour may be compensated by an increase
in skilled labour. Both substitutions between and within capital stocks are allowed.
5.4
Views on Nature
These three types of sustainability can be related to philosophical views on nature. In
literature on nature philosophy, various views on how society deals with its natural
environment have been identified (van Amste11988; Schwarz and Thompson 1990;
Soontiens 1993; Achterberg 1994; van der Wurf 1997). Here the views of conservation,
coevolution and functionality will be used to explain approaches towards substitution
of natural capital. The envisaged substitution possibilities of these views on nature are
illustrated in Fig. 5.2.
5.4.1
Conservation View
The conservation view is mainly concerned with the objective of conserving and restoring the existing natural capital through inte,rventions and isolation. Nature is con-
E.C.M. Ruijgrok . P. Vellinga
Natural capital consists of all natural resources and processes humans make use of.
Produced capital is man made, e.g. machinery stock. Human capital is labour, both in
quantitative (number of workers) and qualitative (skills) terms. Social capital concerns
society's institutional arrangements.
In theory one can distinguish between three types of sustain ability on basis of the
allowed substitutions between and within the four capital stocks: strong sustainability,
moderate sustainability and weak sustainability.
Here strong sustain ability means that the welfare generating capacity of a national
total capital stock may not decrease and that the welfare potential of each of the individual capital stocks may not be diminished. In other words: natural capital may not
be replaced by produced capital and one specific type of natural capital (e.g. forests)
may not be substituted by another specific type (e.g. wetlands). Both substitution betwe~n and within capital stocks are forbidden.
Moderate sustainability will be realized if the welfare generating capacity of both
the total capital stock and of each of the individual capital stocks are not reduced.
Natural capital may not be substituted by produced capital, because the two capital
stocks are considered to be complementary. The welfare generating capacity of a specific part of an individual capital stock may however be reduced here, as long as it is
compensated for by an increase in welfare generating capacity of another part of this
stock. This means that decrease of a part of the natural capital stock (e.g. forests) may
be compensated by an increase of another part of this stock (e.g. wetlands), but not by
an increase in the produced capital stock (e.g. machinery). In other words: substitution between capital stocks is not allowed, but substitution within capital stocks is.
Weak sustainability means that the welfare generating capacity of all four capital stocks
together may not decrease, but it leaves room for substitution. If one capital stock is reduced this may be compensated by growth of another capital stock, as long as the total
welfare generating capacity is not reduced. Now it becomes possible to substitute
e.g. natural capital with produced capital. It is also allowed to have growth or shrink within
one capital stock; a reduction in unskilled labour may be compensated by an increase
in skilled labour. Both substitutions between and within capital stocks are allowed.
5.4
Views on Nature
These three types of sustainability can be related to philosophical views on nature. In
literature on nature philosophy, various views on how society deals with its natural
environment have been identified (van Amste11988; Schwarz and Thompson 1990;
Soontiens 1993; Achterberg 1994; van der Wurf 1997). Here the views of conservation,
coevolution and functionality will be used to explain approaches towards substitution
of natural capital. The envisaged substitution possibilities of these views on nature are
illustrated in Fig. 5.2.
5.4.1
Conservation View
The conservation view is mainly concerned with the objective of conserving and restoring the existing natural capital through inte,rventions and isolation. Nature is con-