Perceptions of efficacy play a central role in motivating people to engage in climate actions. However, there has been little investigation into how different climate efficacy beliefs are formed and how they may be associated with support for climate mitigation policies. This study, based on the motivated control framework, examines how risk perceptions may differentially be associated with four types of efficacy constructs (self-efficacy, personal outcome expectancy, collective efficacy, and collective outcome efficacy). It also places the motivated control framework in the context of the partisan information sphere and examines how exposure to partisan news may influence mitigation policy support through the mediators of risk perceptions and the efficacy constructs. Results suggest that liberal- and conservative-leaning news exposure, respectively, associate with higher and lower supports for policies. Overall, risk perception was a significant mediator, and the mediating function of efficacy varied depending on the specific construct being examined. For liberal news use, increased risk perceptions had a positive association with policy support through self-efficacy and collective outcome expectancy but also had an unexpected negative association with policy support through personal outcome expectancy and collective efficacy. For conservative news use, decreased risk perceptions resulted in further decreased beliefs of self-efficacy and collective outcome expectancy, resulting in lower levels of support for climate policies. We also find that political ideology is a significant moderator for the mediation model. Implications for climate change communication are discussed.