The process of negotiating climate change within the framework of the UNFCCC is, as any bargaining process according to realism as well as liberalism, a power game between the parties involved. Whether states are concerned with absolute gains or care more about relative gains is still widely debated. I contribute to this discussion by analyzing the negotiation outcomes of Copenhagen and Cancun empirically. Furthermore, I intend to explore which variables actually determine bargaining success. Are hard (external) power sources such as economic strength key for countries to achieve their negotiation goals, or are soft (internal) power sources such as negotiation skills equally important? And to what extend does the choice of hard vs. soft bargaining strategies (e.g. threats, promises, change of concessions, etc.) matter for accomplishing these goals? I also examine whether variables which are intrinsically tied to countries, such as vulnerability to climate change, do have an effect on negotiation outcomes and success. These questions are answered using a novel dataset on the current UNFCCC negotiations in which data on success, positions, and strategies of participating parties were collected by interviewing negotiation participants, heads of delegations, as well as negotiation experts. These data will be used in multivariate data analysis to determine which factors are crucial in determining a country’s bargaining success in climate change negotiations.