Combatting climate change misinformation: Evidence for longevity of inoculation and consensus messaging effects

Despite the fact that there is a 97% consensus among climate scientists that humans are causing global warming, the spread of misinformation continues to undermine public support for climate action. Previous studies have found that resistance to misinformation can be induced by cognitively inoculating individuals against doubt-sowing about climate change. However, the long-term effectiveness of this approach is currently unknown. In a preregistered replication and extension experiment we combined a scientific consensus message with an inoculation treatment, and exposed participants to an influential misinformation message one week later. We explored 1) whether we can replicate the finding that inoculation is able to protect against a misinformation attack, and 2) whether or not the consensus and inoculation effects remain stable over the course of one week. Successfully replicating the effects of the original study, we found a strong initial consensus effect that is sensitive to doubt-sowing misinformation. Importantly, we also found that the consensus effect can be inoculated against misinformation. Extending the replication, we found that the consensus effect shows partial decay over time, while the inoculation effect remains stable for at least one week. We discuss the impact of our findings for inoculation theory, climate change psychology, and public policy.