This essay provides an overview of the major emissions trading programs of the past thirty years on which significant documentation exists, and draws a number of important lessons for future applications of this environmental policy instrument. References to a larger number of other emissions...

Two decades have passed since the Clean Air Act Amendments of 1990 launched a grand experiment in market-based environmental policy: the SO2 cap-and-trade system. That system performed well but created four striking ironies. First, by creating this system to reduce SO2 emissions to curb acid...