How sea-level rise (SLR) science is assimilated into decisions on adaptation for coastal lowlands (e.g., land use planning, infrastructure design, managed retreat) will have profound implications for coastal residents, economy, and ecosystems. With a few exceptions1,2, however, there has been little comparative studies of adaptation practice in coastal areas and especially the sea-level scenarios used by decision makers. We used a snowball sampling approach to gain direct insights from planners and coastal decision-makers globally. We used a questionnaire to understand publicly available information about places and their selection of sea level rise projections for use in planning. The questionnaire was conducted online by through Qualtrics and was available in 8 languages.
In this presentation we analyze responses of 254 coastal decision-makers from 49 countries to a survey about the use of SLR projections for adaptation. While nearly all respondents want to consider SLR, only 71% of respondents have formal processes now. In general, developing countries have lower levels of application. There is no global standard practice in the use of SLR scenarios: 53% are planning for a single estimate in 2100, while the others are using multiple estimates, sometimes including an unlikely upper estimate. Places with long histories of adaptation and consistent national support show better assimilation of SLR into adaptation decisions. This survey provides critical insights into the design of improved guidance materials and delivery of climate services.