This dissertation examines market design and operation within the empirical context of CO2 markets. Six case studies are presented which describe business interactions during the design and operation of the Kyoto Protocol, the European Emissions Trading Scheme and the United Kingdom's Carbon Reduction Commitment. The case studies were developed through participant observation between October 2006 and June 2010. The research developed a conceptual framework for the study of CO2 market design and operation. Network-level aspects of CO2 market design and operation were captured by exchange, representational and normalising practices. Macro-level aspects of CO2 market design and operation were captured by technical, temporal and uncertainty based considerations. The conceptual framework was used to analyse the six cases, exploring why CO2 markets have not yet significantly influenced businesses' behaviour. This research should help businesses and regulators to better understand the challenges faced during CO2 market design and operation. Market based approaches to environmental protection are receiving increasing interest in the marketing literature. The conceptual framework and six cases further the study of what is actually happening during CO2 market design and operation, as opposed to previous approaches which have emphasised the intricate theoretical aspects of CO2 market design.