Taking care of free-riders in global warming policies

By now, global warming (or rather global climate change) seems inescapable, with many, many indicators showing a definite trend towards a rapidly changing environment. Given the large scale of this evolution, it is difficult to believe that a simple trick would stop or even reverse it.

David Martimort and Wilfried Sand-Zantman think they found it: get countries to contribute to a general fund and to reduce pollution, but only the most efficient ones at reducing pollution significantly do it. The design of this mechanism is build to solve a double problem: free-riding in participation and effort. The key is to provide a fixed menu of options to countries. This is allows to separate them according to their heterogeneous preferences and abilities, much like insurance companies separate policy holders by offering a menu of policies. In this case, countries would contribute to a green fund more or less, trading this off against subsidies for pollution reduction that are financed from this green fund. The key is that the non-participation of any country would make the whole agreement fail, thus making everyone willing to pay. That is of course under the assumption that no country would actually benefit from climate change. And that it is not too late.