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

Best Case scenario. An ideal case would be to limit the average global temperature change below 1.5˚C. When the emission limiting constant C is high (C = 11), the temperature stays below the desired level and accomplishes the world’s climate goal (Fig 2(c) and 2(f)). The emis- sions decrease within a decade after the rumor propagation begins due to the strong mitigation strategies considered by the rejectors. Keeping the temperature rise below 1.5˚C helps avoid irreversible changes like species extinction and adaptation problems. Our model suggests immediate mitigative actions are required to achieve our climate goals. Average Case scenario. When the emission limiting constant C takes a lower value indicat- ing fewer mitigative actions (C = 1), the emission increases for four decades before declining (Fig 2(b) and 2(e)). In this case, the temperature rises above 1.5˚C and decrease slowly, leading to irreversible environmental changes. Our model predicts that four decadal difference in emission reduction lead to a 200-year delay in achieving our climate goal. Worst Case Scenario. If the emission level does not decrease for another nine decades, the temperature does not decrease till 2300(Fig 2(a) and 2(d)). This situation arises due to poor or no mitigation steps taken by rejectors (C = 0.1). The temperature increases above 2˚C and does not decrease to a desired level, which could lead to unadaptable living conditions. These three scenarios portray the importance of emission mitigating strategies. Even

though the population consists of 80% rejectors, the efficiency of their emission-limiting strat- egies plays a vital role. This result shows that understanding that climate change is a major issue is not enough but to efficiently mitigate is also necessary. 3.1 Sensitivity analysis The time series analysis gave an overall idea about how the model works but to further under- stand the influence of the model parameters, a sensitivity analysis is performed. The parameter planes generated by varying two model parameters simultaneously by retaining all other parameters at the baseline values help to understand how the simultaneous variation in two Fig 2. Emission scenarios for limiting global temperature change. (a) Emissions levels at C = 0.1 (d) Temperature anomaly < 2.5˚C at C = 0.1 (b) Emission levels at C = 1 (e) Temperature anomaly at 1.5˚C (c)Emission levels when C = 11 (f) Temperature anomaly at < 1.5˚C with all other parameters at the baseline values. https://doi.org/10.1371/journal.pone.0317338.g002 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 8 / 18