et al., 2017b; Mori et al., 2018; Ritphring et al., 2018; Hallin et al., 2019; Kasmi et al., 2020). Within regions, projected impacts scale negatively with beach width and positively with the magnitude of projected SLR. None of these local studies, however, considered high-energy storm events, which are known to also impact sandy coasts  , and model structure often had more influence on projected shoreline responses than did physical drivers . Nevertheless, the most- advanced available models, which incorporate multiple coastal processes, including SLR, project that without anthropogenic barriers to erosion, 13.6-15.2% and 35.7-49.5% of the world's beaches likely risk undergoing at least 100 m of shoreline retreat  by 2050 and 2100, respectively  . Aggregating these trends regionally suggests that relative rates of shoreline change under RCP4.5 and RCP8.5 diverge strongly after mid-century, with trends towards erosion escalating under RCP8.5 by 2100  . This trend supports the WGI AR6 assessment that projected SLR will contribute to erosion of sandy beaches, especially under high-
IPCC
Climate Change 2022: Impacts, Adaptation and Vulnerability
IPCC Report