Gaps between what scientists and laypeople find plausible may act as a barrier to learning complex and/or controversial socioscientific concepts. For example, individuals may consider scientific explanations that human activities are causing current climate change as implausible. This plausibility judgment may be due-in part-to individuals' perceptions about the information source and the certainty associated with the message claim. In this study, we examined the relationship among source credibility (trustworthiness and expertise), perceptions of certainty in message claims, and plausibility perceptions about climate change. Our analysis revealed that trustworthiness and message certainty perceptions were significant predictors of plausibility perceptions, above and beyond knowledge about human-induced climate change. These findings suggest that perceptions about information sources may have an important influence on plausibility judgments and, consequently, on learning about controversial and/or abstract concepts.