We suggest that the viability of a climate treaty depends on (at least) two dimensions-the depth of the agreement's emission cuts and the potency of its enforcement system. Thus, to qualify as robust a treaty must satisfy (at least) three conditions:
• Broad participation: A robust treaty must attract participation by a large number of countries, such that carbon leakage and global abatement costs are minimized, and such that the participating countries are not left with an unreasonably large burden.
• Deep emission cuts: A robust treaty must entail deep emission cuts, so that the climate problem is effectively dealt with.
• Effective enforcement: A robust treaty must deter non-compliance by including a potent (i.e., credible and sufficiently severe) enforcement mechanism.
The Kyoto Protocol fails to satisfy these conditions. Under Kyoto, only 36 countries, with less than 30 percent of global GHG emissions, are committed to reducing emissions by only approximately 5% (on average). Kyoto's impact-at best-will therefore be small. A potentially more serious problem is that Kyoto's enforcement system suffers from a number of weaknesses, some of which are serious.
In this project we analyze how a robust climate treaty can be satisfied