Communicating climate change: spatial analog versus color-banded isoline maps with and without accompanying text

People discount projected impacts of climate change that they see as spatially or temporally remote. To overcome this, climate change outreach must communicate impacts as local, concrete, immediate, and situated in a well-understood frame of reference. Spatial-analog mapping may meet this challenge: by drawing on people’s experience of existing climates, this technique matches a locality’s projected climates with present-day climates of other localities. However, analog maps’ effect on climate impact perceptions has not been compared with the effect on climate impact perceptions elicited by standard climate change mapping techniques. Accordingly, this study considers whether residents of Centre Region, Pennsylvania, who are shown spatial-analog maps for future Centre Region temperatures, perceive impacts as more salient than do residents shown the same temperature-change information directly using color-banded isallotherm maps. It also considers how responses differ when this information is presented using only text, only maps, or both maps and text. An online survey of 3094 members of 11 Centre Region organizations presents the maps and/or text and then assesses respondents’ impact perceptions. Based on 444 valid responses, the study finds that respondents, using spatial-analog survey forms, generally expect impacts to be less severe and disruptive than respondents using temperature-change forms. It also finds that respondents using survey forms with maps generally expect impacts to be more severe and disruptive than respondents using text-only forms. Climate change communicators who wish to improve understanding and engagement should therefore strongly consider using maps where possible, but should exercise caution before using spatial-analog approaches.