What Have We Learned From Emissions Trading Experiments?

Emissions trading is a form of environmental regulation in which a regulatory body specifies the total allowable discharge of pollutants, divides this cap into individual permits assigned to individual polluters, and allows trading of the resulting permits. Laboratory experiments, in which paid subjects participate in controlled markets, can be used to test both proposals for emission trading and the theories on which they are based. This paper surveys the laboratory research that has investigated the efficiency of emission trading programs, role of alternative instruments and institutions, the effects of allowing firms to carry inventories of permits, and the extent to which market power can be exercised.