This letter aims to help scholars and practitioners alike prepare for the 15th Conference of the Parties (COP15) to the United Nations Framework Convention on Climate Change (UNFCCC), to be held in Copenhagen in December 2009, by providing a bird's eye view of the increasingly complex terrain of the global climate negotiations. It identifies and explains the most important and contentious 'tripping points' for reaching any agreement on a post-2012 framework, by explaining the primary barriers among countries to reaching consensus and the bargaining chips that countries may draw upon to get there. Namely, the letter details the contours of the ongoing debates on: developed and developing country mitigation; reducing emissions from deforestation and forest degradation (REDD); technology transfer; adaptation; and finance.

This article identifies diverse rationales to call for anticipatory governance of solar geoengineering, in light of a climate crisis. In focusing on governance rationales, we step back from proliferating debates in the literature on how, when, whom, and where to govern, to address the important prior question of why govern solar geoengineering in the first place: to restrict or enable its further consideration? We link these opposing rationales to contrasting underlying visions of a future impacted by climate change. These visions see the future as either more or less threatening, depending upon whether it includes the possible future use of solar geoengineering. Our analysis links these contrasting visions and governance rationales to existing governance proposals in the literature. In doing so, we illustrate why some proposals differ so significantly, while also showing that similar-sounding proposals may emanate from quite distinct rationales and thus advance different ends, depending upon how they are designed in practice.