SOCIAL NORMS FOR THE STABILITY OF INTERNATIONAL ENVIROMENTAL AGREEMENTS

摘要

This paper is devoted to study the stability of international envi-ronmental agreements (IEAs) in a pollution abatement context. Countries candecide to cooperate or to defect. Defector countries decide on their abatementlevels by minimizing their own total cost whereas, signatory countries decideon their abatement levels by minimizing the aggregate of all cooperators.In the model, all countries have the same environmental damage instead,respect to the non-environmental cost, we assume that each signatory countryhas to punish a non-signatory for its behaviour, at some cost to itself (see [17]).We propose two di erent cases in which we have that punishment is directlyproportional to the level of pollution (see [6] or not (see [5]). Punishments canbe in the form of trade sanctions or import tari s, as a measure to encouragecooperation.We model a differential game in order to determine both the optimal path ofthe abatement levels and stock pollutant as results of feedback Nash equilibria.Stability conditions, such as internal and external stability, are applied showingthat di erent answers about the size of a stable IEA can be obtained.