Evidence-based communication on climate change and health: Testing videos, text, and maps on climate change and Lyme disease in Manitoba, Canada

new relationship between lay and expert-based knowledges on climate change, especially con- cerning a doubtful public [43]. At the same time, the other climate visuals tested–the maps–were found to be the least favoured and effective of the three materials, with the combination of technical language, cli- mate model projections, carbon scenarios, and red colouring leaving participants confused or skeptical. Maps have become popular in communicating scientific information on climate change over the past decades, as they can be particularly effective when hazards have a spatio- temporal component [44]. However, the use of scientific images in climate communications (e.g. maps, graphics) often depict climate change as a natural process and may not compel individual action, thus leaving viewers feeling powerless [45]. In our study, people found the maps alarming or impactful, few understood them fully, and many expressed negative feelings towards them as a result. Research on climate information websites designed to share down- scaled climate data have found similar results, as these sites often assume a higher level of understanding of scientific concepts and associated jargon among their users than there actu- ally is [15]. Another common critique among participants related to the “colour ramp” of maps, which people felt was scary, confusing, or deceiving. Colour ramps portray not only the data but also evoke different emotional reactions, carrying cultural associations such as red for

danger [37,46], and these various design choices can trigger differentiated responses that affect the perceived credibility of climate maps and visualizations [47]. Compared to the video, the more complex mapped climate projections were not as comprehensible for the vast majority of participants. While the medium of video, and to a lesser degree the article, translates climate science through narrative and emotion, climate projection maps did less to translate the knowledge. Arguably, a more sequenced approach for climate communication when engaging audiences of low knowledge or concern on climate change might be: (1) video that incorpo- rates storytelling as a tool for initial engagement; (2) articles with narrative and visual compo- nents as a second step; and (3) more complex climate maps once the audience has been engaged. Maps are a critical tool to communicate scientific information, but may require more audience knowledge and participation in decoding the information, and are perhaps most effective in combination with other climate visuals and contextual information. The need to clarify the message: Health or climate? A key finding relates to the confusion about the main message and purpose of all communica- tion materials. Many participants were unsure if the purpose of the materials was to promote action to mitigate climate change or to encourage adaptive behaviours in response to the increasing risk of Lyme disease, and most suggested choosing one or the other would make the

materials more effective. This seems to challenge the emerging climate communications litera- ture that suggests that health is an important frame for effective dialogue with an increasingly polarized public [9,48,49]. Indeed, public health communicators are also developing best prac- tices for communication around the health effects of climate change [50]. The results here suggest that marrying public health and climate change information is not as straightforward as it may seem, as the association of the two topics may draw skepticism from those already unconvinced or skeptical of climate change. In this context, it seems that “strategically decoupling” the two issues in communications might be more effective in some cases, especially if the primary goal is to motivate adaptive health behaviours among skeptical or mixed opinion audiences [51]. However, if the goal is to increase awareness regarding the human dimensions of climate change, reframing climate change from an environmental to a human health issue is essential. At present, there is a need to critically evaluate what a health frame in climate communications looks like, and these results suggest a broader approach that PLOS ONE Evidence-based communication on climate change and health PLOS ONE | https://doi.org/10.1371/journal.pone.0252952 June 10, 2021 10 / 17