Geoscience Reference
In-Depth Information
protection. The complexity of ecosystems and the combined effects of
contemporaneous human and natural disturbances prevent the identi-
ow from harm to
their components. They also prevent the accurate prediction of harm
to components themselves as outcomes depend on resulting change in
the structure and function of the ecosystems of which they form part.
However, knowledge of the propensity of systems to change state also
points the way to an alternative approach to decision-making, and one
that may provide stronger justi
cation of impacts at the systemic level that may
cation for constraining economic
growth on environmental grounds. The key information is that ecosys-
tems can, if the cumulative stresses placed on them prove too great,
withdraw the support that they provide to dependent humans by shifting
to subsistence states. This may occur with little or no notice and in ways
that are irreversible. The signi
cance of regime shifts is reinforced by
knowledge of the impact that widespread ecological deterioration could
have on Earth System processes with knock-on effects for the functioning
of all ecosystems. In view of this, the goal of efforts to preserve ecosystem
functionality should be to identify and sustain those elements of ecosys-
tems that enable them tomaintain their structures and functions. Proposals
for development or resource exploitation under consideration should not
be permitted when they could jeopardise the capacity of ecosystems to
resist external disturbance.
Two aspects of ecosystem functionality must be considered further
to establish whether an ecological perspective in decision-making would
enable a clearer line to be drawn between environmentally tolerable and
intolerable actions and modes of human behaviour, and if so, how. First,
what elements of ecosystems enable them to remain in states that
provide support for human living? Second, how are ecosystems placed
at risk of failure? This information is required to be able to determine
how activities should be governed to try and reduce risks of regime
shifts occurring. To explore these matters, it is necessary to consider
the systemic property of resilience that ecological scientists have identi-
ed as being of central importance for preventing regime shifts in
ecosystems. I examine aspects of this property that we need to be clear
about if resilience is to provide a focal point for the development of legal
structures to protect ecosystems in the following sections. These include:
its meaning when used in the context of ecosystem functionality; what is
it that makes an ecosystem resilient; whether resilience is a property that
can be quanti
ed; and, if so, can controls be imposed on activities by
reference to measurement of the resilience that a system possesses?
