Offsets lower the cost of cap-and-trade programs but must be considered imperfect if they cannot exclude “non-additional” emissions reductions or sequestration gains that would have occurred in their absence. Non-additionality can be addressed by requiring project-level additionality tests,...

The 1990 amendments to the Clean Air Act created a trading program in sulfur dioxide (SO2) emissions that has served as the seminal example of how an emissions trading program could be designed. Yet despite its success, the trading program was essentially brought to an end by a series of...

NutrientNet is an Internet-based environment in which a class can simulate a market-based approach for improving water quality. In NutrientNet, each student receives a role as either a point source or a nonpoint source polluter and then the participants are allowed to trade water quality credits...

The use of transferable discharge permits as a water pollution control policy is rapidly increasing in the United States. Drawing on evidence from existing water quality trading programs, this paper provides a taxonomy of the forms that such markets take. Four main structures are identified:...