The political roots of divergence in carbon market design: implications for linking

There is a substantial literature on optimal emissions trading system (ETS) designs, but relatively little on how organized political interests affect the design and operation of these economic instruments. This article looks systematically at the political economy of the diffusion of ETS designs and explores the implications for carbon-market linking. Contrary to expectations of convergence – as has been observed in many areas where economic policy diffuses across markets – we found substantial divergence in the design and implementation of ETS across the nine systems examined. The architects of these different systems are aware of other designs, but they have purposely adjusted designs to reflect local political and administrative goals. Divergence has sobering implications for visions of ubiquitous linkages and the emergence of a global carbon market that, to date, have been predicated on the assumption that designs would converge. More such ‘real world’ political economy analysis is needed to understand how political forces, mainly within countries, act as strong intervening variables that affect instrument design, implementation and effectiveness.Key policy insights Our finding of design divergence indicates that policy efforts aimed at achieving integrated international markets are unlikely to be successful. Visions of carbon market linkage will need to confront the reality that there are well-organized political coalitions, anchored in the status quo, that prefer divergence. In linking ETS, policy-makers should devote more attention to preventing excessive capital flows that can undermine political support for linkage, while also creating incentives for convergence in trading rules over time.