Climate-denying rumor propagation in a coupled socio-climate model: Impact on average global temperature

the strategies adopted. The more time we take to reduce our emissions, the higher the average global temperature anomaly will be. The coupled rumor-climate model suggests that misinfor- mation via rumors is a significant issue. The effort the rejectors make to mitigate climate change is vital in controlling the time taken for decreasing the emission level, and temperature changes. Our simple rumor-climate model shows that the temperature anomaly is more sensitive to mitigating strategies than believing or not believing the climate rumors. Surprisingly, the tem- perature becomes less sensitive to the variation in rumor propagation parameters as time passes. Our results show that larger groups assist in rapid rumor propagation and hence in temperature deviations. The univariate sensitivity plots infer that having larger groups with more members is more efficient in propagating rumors and reducing the temperature than having more groups with fewer members. In other words, the decision of a group with more members has more influence on the temperature levels than smaller groups. The coupled model also portrays that group propagation is faster than individual propagation and hence has more influence on the temperature anomaly. Decreasing the connectivity of individuals does not influence the number of rejectors in the population when a high volume of rumors is sent in groups. The average rate of messages sent in groups produces more variation in the temperature levels, and temperature is more sensitive to group propagation parameters than

individual propagation parameters. Our model deals with arbitrary decision-making in the rumor propagation model by considering that the whole population either believes or rejects the rumors. In contrast, decision-making might be influenced by the individual’s cultural, political, educational, or social views, which is not covered in this model. The spread of rumors about climate change can be controlled using various methods such as inoculations through educational approaches and social norms [67]. Proper climate education is necessary for indi- viduals to distinguish between rumors and facts about climate change and take the right deci- sions by considering mitigation and adaptation strategies. Several models deal with climate change, but models involving human influence on climate change are rare. The recent development of coupled social-climate models have included social and economic factors [27, 33, 37], but ours is the first social-climate model to include rumor propagation, to our knowledge. Social networks act as an essential medium of information cir- culation, therefore it is crucial to understand how rumor propagation in a heterogeneous social network can influence individuals’ opinions on climate change. According to our model, social networks have a vital role in influencing the climate system. Coupled models can be beneficial in including dynamic social processes in climate models. Including these models in climate change research can provide different perspectives and predictions regarding climate change.

Coupled models can also help in policy-making by providing novel emission scenarios based on social mechanisms that are known to be important. Also, according to our model, using individuals in social networks to become aware of climate change issues could be beneficial to reduce emissions by increasing the number of mitigators in society. Social networks act as an important way of spreading information regarding climate change and inviting more individ- uals to act at the right time. Supporting information S1 Fig. Flow chart with steps of conducting the study. (TIFF) S2 Fig. Temperature change is sensitive to both believing and rejecting probability in groups. (a-c)Parameter planes of CO2 emissions (GtCO2 yr-1) at (a) 2021, (b) 2070, and (c) 2200 and (d-f) temperature changes (˚C) at (d) 2021, (e) 2070 and (f) 2200 by varying group PLOS ONE Climate-denying rumor propagation in a coupled socio-climate model: Impact on average global temperature PLOS ONE | https://doi.org/10.1371/journal.pone.0317338 January 16, 2025 13 / 18