As a system of regulation which employs tradable instruments to achieve public policy goals, emissions trading has emerged as a persuasive solution to the global problem of climate change. However, significant contention exists in respect of the use of tradable permit regimes to counteract air pollution èˆ' for example, that they do not reduce emissions as such, that they stifle innovation, and that they disadvantage developing countries. Moreover, many highlight the failure of such regimes to deliver significant levels of emissions abatement that can make a real difference to climate change policy.