Designing an indicator of environmental responsibility

When an environmental problem involves several agents, different environmental indicators can be chosen. In this paper we derive axiomatically an indicator of "environmental responsibility", the quantitative contribution of each agent to the environmental problem. This indicator must possess properties that most agents are likely to accept. Apart from a normalization condition, that indicator must be: (1) additive, implying that the responsibility of a set of agents is the sum of the responsibilities of each agent; (2) account for indirect effects under economic causality, implying that the agent that benefits economically from an environmental damage is responsible for it; (3) monotonic in direct environmental pressure, implying that the responsibility of a given agent cannot decrease if its actions lead to an overall worsening of the environmental problem; (4) symmetric in production and consumption, meaning that if the contribution of an agent's consumption and production behavior is interchanged, that agent's responsibility cannot change. We prove that an indicator fulfilling these properties exists and is unique, given by the average of the environmental pressure generated to produce the primary inputs and the final demand of an agent. The existence of a unique indicator of environmental responsibility can facilitate cooperation in environmental agreements and raise commitment in the implementation of environmental policies.