International climate policy negotiations are increasingly shifting from emission targets towards financial commitments. A major element of this process is the promise of industrialized countries to mobilize from 2020 on annually 100bn USD to finance mitigation and adaptation projects in developing countries. Despite its relevance, there is remarkably few evidence about the effectiveness of investment support programs and policies. So far, climate finance has been mainly analysed from a rather abstract strategic or fairness perspective. There is a need to improve our understanding of the actual impact of internationally supported climate finance projects on the reduction of carbon emissions and co-benefits such as poverty reduction.