The Five Canadas of Climate Change: Using audience segmentation to inform communication on climate policy

ensure the validity and stability of our findings, we conducted the analyses using 5 000 random sets of start values and replicated each solution ten times. All three models (4-,5-, and 6-seg- ments) replicated exactly. Several measures can be used to identify the correct number of classes and help choose the model that best fits the data (Table 2). Classical fit indices–including the Bayesian information criterion (BIC), sample-size adjusted Bayesian information criterion (SABIC) and the Table 1. Variables used to create the segmentation (vs. items used in Global Warming’s Six Americas). Variables used to create the segmentation Global Warming’s Six Americas (Maibach et al. 2011) Motivations • Certainty global warming is occurring • Human causation (% agree global warming is occurring and is mostly caused by human activities) • Personal risk perception • Timing of harm to Canadians • Knowledge • Climate change discussion frequency • Attitude toward the environmental movement� • Importance of climate change for electoral decisions� Motivations • Certainty global warming is occurring • Human causation (% agree) • Scientific consensus • Personal risk perception • Future generation risk perception • Risk on animals and species • Timing of harm to Americans • Ability of humans to successfully mitigate climate change • Actions of individuals can make a difference • Technological optimism • Perceived impact of own mitigation actions • Impact of own actions if widely adopted in the U.S. • Impact of own actions if widely adopted in modern industrialized countries

• Rating of Global warming (1 = good to 6 = bad) • Level of worry • Thought given to global warming • Need for information (4 = low need) • Personal importance of issue • Unwilling to change opinion • Personally experienced global warming • Global warming discussion frequency • Friends share views on global warming Behaviours • Contacted government officials about mitigation • Rewarded/punished companies that are/are not reducing emissions • Reduced household’s use of energy+ Behaviours • Contacted government officials about mitigation • Rewarded companies that reduced emissions • Intend to reward companies that reduce emissions • Punished companies that are not reducing emissions • Intend to punish companies that are not reducing emissions • Stage of change for lowering thermostat in winter • Stage of change for using public transportation or car pool • Stage of change for walking-biking instead of driving • Stage of change for CFL use Preferred societal responses • Primary responsibility for paying the financial costs of climate change+ • Support for holding companies accountable+ Preferred societal responses • Priority of global warming for president and Congress • Corporations should do more-less to reduce warming • Citizens should do more-less to reduce warming • Desired US effort to reduce warming, given associated costs • Contingent int’l conditions for US mitigation action (% regardless of actions in other countries) Total : 13 variables + Adapted � Added Total : 36 variables https://doi.org/10.1371/journal.pone.0273977.t001 PLOS ONE

The Five Canadas of Climate Change PLOS ONE | https://doi.org/10.1371/journal.pone.0273977 November 23, 2022 6 / 21