International environmental agreements under different evolutionary imitation mechanisms

This paper explores how the formation and stability of international environmental agreements vary with two often adopted mechanisms: imitating-the-best-average and imitating-the-best-total rules. We first show that the possible long-run equilibria of two dynamics are the same. They are countries' full participation, no-participation, and the two equilibria combined. However, the occurring conditions of these equilibria under two dynamics may differ. Then, we prove that countries' full participation is more likely to be long-run equilibrium in international environmental agreements when imitating-the-best-average rule is adopted. Moreover, all findings of this study hold whatever the function forms of countries' abnoatement benefits and costs are, and are unaffected by the positive affine transformation of countries' total payoffs.