This article reviews recent developments in global carbon governance. The focus is on three emerging trends that result from stalemates in intergovernmental negotiations, but may also further complicate decision-making. First, uncertainties and complexities in global carbon governance have given rise to a stronger role of actors beyond the nation state. Second, this new emergence of multiple-actor governance, along with spatial and functional interdependencies, has stimulated the emergence of new mechanisms of global carbon governance, namely transnational regimes, transnational public policy networks and transnational markets. Third, the overall complexity of global carbon governance, along with the stakes involved and resulting negotiation stalemates, has led to a fragmentation of the policy system with multiple spheres of authority that requires new types of interplay management. © 2010 Elsevier B.V.