Implementing a global shoreline model

Many of the world’s sandy coastlines experience significant seasonal and inter-annual variability, driven by both natural and anthropogenic factors. Natural influences include sea-level fluctuations, sediment imbalances typically caused by wave action, and changes in sediment sources from continental regions, while anthropogenic influences also play a role. This study focuses on the challenges of implementing a global shoreline evolution model which adapts the physics of smaller-scale local models to the much larger scales characteristic of climate models, typically on the order of 100 km. By incorporating regional dynamics and often overlooked factors such as sediment exchange, riverine inputs and sea level variations, this study aims to capture how coastal regions respond to climate-induced multi-factor stresses. Using optical satellite-derived coastlines, satellite altimetry data and model reanalysis, we test whether a simplified representation of complex processes can effectively reveal key regional patterns and sensitivities to climate drivers. • GLOBCOAST simplifies shoreline processes to capture broad global trends in coastal evolution. • The model assesses coastal sensitivity to key drivers like waves, water levels, and terrestrial runoff. • It reveals large-scale coastal variability, offering insights into global responses to climate changes.