Fossil fuel–rich developing countries should be included in climate change mitigation. But they need money, above what rich countries have been willing to provide, to do so. I argue that existing approaches to international and intergenerational transfers have failed to bridge the gap between developing and developed countries’ interests. I present a new model in which the costs of present climate action are distributed not according to present or historical wealth but according to future wealth. I demonstrate the basic feasibility of this approach with an implementation I call income-adjusted guarantees. I argue that such an arrangement can help accelerate fossil fuel retirement in developing countries and break the deadlock over global climate financing.