Toward a positive theory of coalition formation and endogenous instrumental choice in global pollution control

The paper analyzes the coalition formation process in a global emission game with asymmetric countries where the number of signatories, the abatement target and the policy instrument are chosen simultaneously. Exemplarily, a uniform emission reduction quota and an effluent charge are considered. Stability is analyzed in a supergame framework by applying the concept of coalition-proofness. The analysis also considers the impact of impatient agents, restricted and simple punishment profiles. Two main results may be mentioned: First, paradoxically, IEAs achieve only little (if signed at all) if the externality problem is distinct. Second, the authors' model helps to explain the frequent appearance of emission quotas in international pollution control despite the recommendations by economists to use market-based instruments like effluent charges.