System sustainability

The concept of sustainability can only be conceived in a systemic framework. No system considered in isolation from its environment (latu sensu) can act sustainably, therefore sustainability connotes a system within its context. Some crucial features are identified here to describe the concept and avoid misuse of the term. These are time, biophysical limits and relationships, according to which a system, project or action can be considered sustainable. Nature is the quintessence of sustainability. Human systems must obey the laws of nature and follow nature’s way in order to be sustainable. Sustainability traditionally conceives the economic system as being within the social system, which is in turn included and supported by the environment as resource and service provider and waste absorber. This organic view is composed of networks that connect these three spheres and the elements within them. Many approaches embrace a systemic view to identify and evaluate the sustainability of a system and to encompass the many dimensions that characterize this concept. Ecosystem services, the energy-food-water nexus, planetary boundaries defining the safe operating space for humanity and UN Sustainable Development Goals are only a few examples. Here we also shed light on the Input-State-Output approach.