The Warsaw conference, 2013, marked the halfway point from the Durban conference, 2011, that launched negotiations towards a 2015 climate agreement and the Paris conference, 2015, slated as the deadline for these negotiations. As such, the Warsaw conference needed to register a step change in the process—from the airing of differences to negotiating them. It also needed to create the conditions necessary to reach agreement in 2015. This article analyses the outcome of the Warsaw negotiations with a view to determining the extent to which it paves the way for a 2015 climate agreement. In particular, this article explores the divisions over, prospects for and contours of a likely 2015 agreement. The 2015 agreement is likely to be shaped by the resolution Parties arrive at on three overarching issues. These are: architecture—whether the agreement will be ‘top-down’ (prescriptive) or ‘bottom-up’ (facilitative) or a hybrid version of the two; differentiation—the nature and extent of it, and in particular whether it will eschew or replicate the Kyoto model of differentiation and related vision of equity; and legal form—whether the 2015 agreement will be legally binding, and if yes, as is likely, which elements of the 2015 package will be in the legally binding instrument and which elements will be in non-binding complementary decisions. The Warsaw outcome will therefore be analysed with a view to providing insights into the likely architecture and legal form of as well as treatment of differentiation and equity in the 2015 agreement.