Climate change belief systems across political groups in the United States

norm theory. First, role modeling can help individuals learn and adopt similar emotional states from a trusted figure [28]. Second, role modeling can help establish a perceived social norm that worrying about climate change is common, proper, and even imperative. The impact of worry modeling could be further amplified by utilizing multimodal content that includes non- verbal cues, such as facial expressions and tone of voice, providing immediate indicators of emotional urgency [29]. We call for future research to investigate the potential of this intrigu- ing strategy. Estimating belief systems at the aggregate level presents another caveat. While using nation- ally representative survey data allows us to approximate the belief system of an average individ- ual within a given group [30], it does not necessarily follow that all individuals in that group share the same belief system structure. Promisingly, recent studies have attempted to estimate belief systems at the individual level [31]. Future research could try to match belief system analysis at multiple levels to identify similarities and differences. The findings of this study should also not necessarily be generalized to other countries. Although climate change is a global issue, public beliefs and attitudes toward climate change vary widely by country [32]. The U.S. likely has substantially different climate change belief systems than other countries in this regard. Given the tremendous variation in public responses to climate change around the world, climate change beliefs systems are also likely to

vary. Belief systems are presumably affected by many factors such as culture, education, and other socio-economic factors. As the belief system framework can provide valuable insights for the development of strategic climate change communication, implementing the belief system framework on a global scale is encouraged. This could shed light on the diversity of belief sys- tems around the world and help us develop more effective communication strategies that take into account the context of each country. Overall, the findings demonstrate that the belief system approach is a valuable framework that enriches our understanding of the organization and interplay of different climate change beliefs. Worry about climate change is identified as the central element in American climate change belief systems. Over the past decade, the organization of belief systems among politi- cally disengaged individuals has increased, implying that improved climate change communi- cation is helping people develop more coherent and cohesive belief systems on the subject. Despite the pronounced discrepancy in the strength of beliefs between the political left and right, our findings reveal a structural similarity in how belief systems are organized within these two groups. Collectively, these insights can guide the development of effective climate change communication strategies. Supporting information S1 Fig. Centrality stability. (TIF) S2 Fig. Intra-group comparison of belief system after removing outliers. (TIF) S3 Fig. Inter-group comparison of belief systems after removing outliers. (TIF)

S1 Table. Betweenness centrality difference between worry and other elements. (DOCX) S2 Table. Closeness centrality difference between worry and other elements. (DOCX) PLOS ONE Climate change belief system PLOS ONE | https://doi.org/10.1371/journal.pone.0300048 March 20, 2024 14 / 16