The assessment of environmental sustainability of ecosystems, productive processes and territorial systems requires a holistic approach, based on thermodynamic functions and able to consider all the complex mechanisms which are involved in a system. Many of the most used indicators focus their attention on single aspects and do not consider the system as a whole. The SPIn-Eco project uses a holistic and integrated approach so as to assess the sustainability of the Province of Siena with a set of environmental tools. One of these is the emergy analysis. This environmental accounting methodology is able to compare the value of human and natural systems on a common basis: the quantity of solar energy directly and indirectly required for a process. This quantity, called emergy, represents the memory of all the energy, matter and time that the biosphere used up to make a product available. The emergy indicators permit one to evaluate the efficiency, the environmental stress and the sustainable use of resources involved in a single process or in systems at various scales. The indicators define a Province with a low environmental loading ratio, which is the ratio between non-renewable and renewable resources, due to a low anthropic activity, well integrated with the characteristics of the territory, to a low population density and internal production of electricity by means of geothermal heat. The Province of Siena has the lowest emergy per area of the Italian territories examined up to now. It is mainly sustained by non-renewable resources (91%), of which 62% are from local resources (mainly from extractive materials) and 29% is imported through commerce. These results show a low dependence on external resources and suggest a careful monitoring of material extractions. This avoids a systematic loss of natural capital. Moreover, they suggest developing processes of material recycle and recovery. The renewable use(9%) is not so low compared to the other Italian territories.
展开▼
