How Persuasive Are the Most-Cited Climate Change Messages? A Registered Report Megastudy

How persuasive are the most-cited climate change messaging strategies? In five replication studies, we found limited evidence of persuasive effects of three highly cited strategies (N=3,216). We then conducted a registered report megastudy (N=13,544) testing the effects of the 10 most-cited climate change messaging strategies on Americans’ pro-environmental attitudes and behavior. Six messages significantly affected multiple preregistered attitudes, though effects were small (≤ 15% of the Democratic-Republican gap) and similar in magnitude across messages. Persuasiveness varied little across party lines, contradicting theories predicting heterogeneous effects for targeted messages. No message increased pro-environmental donations, highlighting the challenge of influencing costly behaviors through messaging alone. The most impactful messages influenced multiple mediating variables, limiting identification of the specific mechanisms driving effects. Taken together, these results identify several persuasive strategies, yet also highlight important limits of short-form messages for increasing Americans’ support for action to address climate change.