On Climate Agreements with Asymmetric Countries: Theory and Experimental Results

Résumé

I model International climate agreements among asymmetric countries, each of whom must select a profile of CO2 emissions over time. Predictions from this model imply larger reductions by “large” countries, but larger proportional reductions by “small” countries. I then analyze experimental data that sheds light on this issue. In contrast to the theoretical predictions, I find that smaller countries do not reduce emissions proportionately to their Nash level, and so the burden falls mostly on larger countries. Moreover, combined emissions are indistinguishable from the one-shot Nash emissions. This pessimistic outcome extends the commonly-found result in the literature that negotiations in similar repeated games (but with symmetric players) generally do not offer much hope for meaningful agreements, unless the effects are modest.