Comparing the effectiveness of different consensus messages in communicating global environmental issues: The role of referent groups, emotions, and message evaluation

Considering effective messaging strategies as one important way of mobilizing the general public to join the fight in addressing some of the world's most critical environmental problems, this study compared the effectiveness of different consensus messages that varied in referent groups and content in communicating two global environmental issues. It proposed and tested a theoretical framework that includes two mediational pathways leading to changes in policy support. U.S. adults (N = 2296) were randomly assigned to 1 of 16 experimental conditions as part of a 4 (consensus message: control vs. seriousness vs. anger vs. hope) × 2 (referent group: scientists vs. public) × 2 (issue: plastic pollution vs. biodiversity loss) between-subjects factorial design. Overall, the proposed framework received solid support in both contexts. Scientific (vs. public) consensus was found to be more credible, which positively influenced policy support. Anger consensus (vs. control) worked through perceived anger consensus and then anger to increase policy support. In contrast, hope consensus and the feeling of hope were largely ineffective in improving policy support. These findings contribute to a deeper understanding of the potentials and limitations of consensus messaging in communicating global environmental issues.