An exergy-based Ecological Indicator as a measure of our resource use footprint

The concept of 'Ecological Indicator' (EI) is critically analysed to define the properties it ought to possess and to demonstrate that indicators based solely on material-and energy balances do not comply with the necessary properties. It is argued that exergy destruction and exergy of discharge, both acceptable thermodynamic indicators, cannot provide information on the human-specific impact of a pollutant (neither of them measures toxicity and non-energetic externalities). A recently proposed method, Extended Exergy Accounting (EEA), which includes in the exergy flow diagrams non-material and non-energetic production factors like labour, capital and environmental remediation costs, is shown to provide a proper measure of the amount of primary exergy resources consumed in the life-cycle of a material or immaterial commodity.