Globally, along sandy coastlines, foredunes support ecosystem services including provision of habitat and protection of communities from waves and storm surge. In this Review, we discuss the interactions between sand transport and vegetation processes (ecomorphodynamics) that give rise to the foredune-building feedback as illuminated by empirical and modelling studies. Foredune shape and alongshore continuity depend primarily on sand supply, vegetation density and growth form. For instance, low-lying, creeping herbaceous species tend to form short embryo dunes, whereas tall, dense grasses that grow vertically tend to form tall, narrow foredunes. Climate and weather events, herbivory and anthropogenic disturbances of varying scale affect the foredune-building feedback. For example, small local scale disturbances, such as herbivory or trampling, cause local vegetation loss and erosion. Management activities, such as beach nourishment, can increase foredune sand supply, leading to foredune rebuilding, although the presence of infrastructure on the back beach can inhibit foredune development. At a regional scale, hurricanes and tropical storms cause substantial dune erosion and overwash, potentially resetting the foredune-building process. Sea-level rise exacerbates the effects of storms, leading to increased erosion, saltwater intrusion and a potential landward shift in foredune location. Future research should prioritize integrated ecomorphodynamic observations and modelling to fill critical knowledge gaps and address the effects of changing climate on the foredune-building process.

Shifts in the frequency of typical meteorological patterns in an ocean basin, over interannual to decadal time scales, cause shifts in the patterns of wave generation. Therefore, ocean basin-scale climate shifts produce shifts in the wave climates affecting the coastlines of the basin. We present a hybrid methodology for downscaling observed (or predicted) climate shifts into local nearshore wave climates and then into the associated coastline responses. A series of statistical analyses translate observed (or predicted) distributions of meteorological states into the deep water wave climate affecting a coastal region and dynamical modeling combined with statistical analyses transform the deep water wave climate into the nearshore wave climate affecting a particular coastline. Finally, dynamical modeling of coastline evolution hindcasts (or predicts) how coastline shapes respond to climate shifts. As a case study, we downscale from meteorological hindcast in the North Atlantic basin since 1870 to the responses of the shape of the coast of the Carolinas, USA. We test the hindcasts using shoreline change rates calculated from historical shorelines, because shifts in coastline shape equate to changes in the alongshore pattern of shoreline change rates from one historical period to another. Although limited by the availability of historical shorelines (and complicated by historical inlet openings), the observations are consistent with the predicted signal of ocean basin-scale climate change. The hybrid downscaling methodology, applied to the output of global climate models, can be used to help forecast future patterns of shoreline change related to future climate change scenarios.