Unintended consequences of using maps to communicate sea-level rise

Sea-level rise caused by climate change poses enormous social and economic costs, yet governments and coastal residents are still not taking the mitigation and adaptation steps necessary to protect their communities and property. In response, advocates have attempted to raise threat salience by disseminating maps of projected sea-level rise. We test the efficacy of this ubiquitous communication tool using two high spatial-resolution survey experiments (n = 1,243). Our first experiment, in US coastal communities across four US states, exposes households on either side of projected sea-level rise boundaries to individually tailored risk maps. We find this common risk communication approach has the unintended consequence of reducing concern about future sea-level rise, even among households projected to experience flooding this century. In a second experiment on our sample (n = 737) of San Francisco Bay Area coastal residents, direct communications about impacts on traffic patterns does increase concern about future climate impacts. Map-based risk information increases support for collective spending on climate adaptation, but it does not increase individual intentions to contribute. Our results demonstrate the importance of empirically testing messaging campaigns for climate adaptation. Getting coastal residents to understand the risk of rising sea levels can be difficult. This study finds that showing individuals top-down maps of future sea-level boundaries can be counterproductive to making residents concerned about climate impacts.