uction In 2007, both houses of the US Congress began serious consideration of proposals to regulate carbon emissions in response to escalating concerns about global warming. One approach, which has been incorporated in legislation reported out of the Senate Committee on Environment and Public Works, would require the US government to adopt a “cap and trade” system that would apply to domestic carbon emitters and, ultimately, to imports.3 In broad outline, such a cap and trade system CCLR 1|2008 43 Emission of greenhouse gases is a glo