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

salient in a communicative context–can also have a meaningful and significant impact on the public’s support for policies [e.g., 63, 64]. These kinds of efforts at communicating certain aspects of carbon tax designs or highlighting the relative costs of alternative policy measures on public support for carbon pricing can be thought of as emphasis frames. In contrast to equivalency frames, which present an issue or political choice in different but logically identi- cal ways, emphasis frames emphasize a subset of potentially relevant features of an issue over others [35, 36], thus varying how the information is presented and its content [38, 65]. While some scholars have argued for a narrower definition of framing that would exclude emphasis frames [38]–notably because these effects are difficult to distinguish from other communica- tion effects–the literature suggests that the two types of influences are important in shaping cit- izens’ political preferences, similarly wielding on average medium-sized effects on political attitudes and emotions across studies and contexts [66]. In light of the insights provided by the literature on audience segmentation for climate change communication, we designed a survey instrument intended to help identify specific cli- mate change audiences that exist in the Canadian population. Informed by the literature on communicating around carbon taxes, we also embedded an experiment in the same survey to assess the reactivity of climate change audiences in Canada to messages (i.e., emphasis frames) intended to build support for carbon taxes.

Methods In order to examine the public’s reactivity to alternative ways of communicating around car- bon taxes, we analyze data drawn from a random probability sample of 1207 adult residents of Canada. This survey was approved by the University of Montreal’s Ethics Review Board (certif- icate CERAS-2017-18-105-D) and consent to participate was informed. The data were col- lected using a random digit dialing (RDD) telephone survey with a disproportionate stratified sample of adult Canadians aged 18 years and older. An overlapping dual-frame (landline and cell phone) sample was used. Interviews were conducted between 6 and 29 October 2017 in English and French. Using the American Association of Public Opinion Research method of calculating response rates (AAPOR RR3), we obtain a combined response rate of 9%, which is typical for this method of data collection and has been shown to provide valid estimates with limited bias from unit nonresponse [67]. Audience segmentation To segment the data into distinct audiences, we followed the approach of Maibach and col- leagues [15] and used three categories of variables as criteria for the segmentation: motivations, behaviours and preferred societal responses. However, we did not measure the full 36 variables that were used in the Global Warming’s Six Americas, as research has demonstrated that valid audience segmentation models can be obtained using a subset of 15 [15] or even 4 [68] items. The questions available in our survey allowed us to measure motivations, behaviours and pre-

ferred societal responses with 13 variables, 11 of which were very similar to those used in the Six Americas (see Table 1). As shown in Table 1, three of these items were slightly adapted to the Canadian context and two others were added because they considerably improved the pre- dictive power of our models (i.e., attitude toward the environmental movement and impor- tance of climate change for electoral decisions). We conducted a Latent Class Analysis (LCA) using Latent Gold 5.1, and used these 13 vari- ables to submit four, five and six segment solutions to the analysis. To guard against local max- imum solutions when conducting LCA, one efficient technique is to run the estimation algorithm several times with different parameter start values [15]. To address this issue and to PLOS ONE The Five Canadas of Climate Change PLOS ONE | https://doi.org/10.1371/journal.pone.0273977 November 23, 2022 5 / 21