The Oslo protocol on sulfur reduction: the great leap forward?

The increasing number of international environmental agreements (IEAs), and the fact that under some agreements emissions have been reduced beyond agreed targets, are frequently viewed as success stories of international cooperation. We argue that success can only be measured if abatement targets under an IEA are compared with estimated abatement levels in the absence of a treaty, and are evaluated in terms of costs and benefits. We analyze the Oslo Protocol on sulfur reduction, showing that this IEA is not the great leap forward when compared with the calculated Nash equilibrium and the social optimum. However, we also demonstrate that under the Oslo Protocol, more ambitious targets could not have been realized due to strong free rider incentives.