ng them with wastes, others by over-exploitation, others still by destructive actions. This has reduced their productive capacity, their adaptability, their resilience and the quality of their services. Hence, we have already reduced the probability of sustainability for future generations. Therefore, as society moves towards equilibrium with the environment, we should also seek to restore we have caused to become degraded.
A sustainable society is one that is in equilibrium with its environment having closed the loops between its inputs and outputs. It differentiates between renewable and non-renewable resources, ensuring that ecosystems can supply or recycle the former while recycling the latter itself. It avoids making changes to the environment but where changes are outside its control, it ensures that both the systems within society and the ecosystems within the environment can adapt to those changes until a new equilibrium is attained. Likewise, it ensures that both are resilient to transient shocks.
Our society may have a long way to go and sustainability may not be certain, but restoring the productivity, adaptability and resilience of the ecosystems it has degraded will only help. The harnessing of renewable resources and using them more efficiently are areas of where improvement is vital. Finding new ways to recycle non-renewable resources or replacing them with renewable substitutes are opportunities for innovation. Clearly greater cooperation in managing ecosystems and allocating resources is going to become increasingly important. Not everything needs to be done immediately but some actions are more urgent than others and they need to be identified and priorities set.
By looking at their inputs and outputs, it can be simple to determine which parts of a system are not sustainable, but it is often meaningless to say that one part is sustainable without considering the whole. Therefore, it may be impossible to achieve sustainable development but development towards sustainability can be and should be our goal.