Extreme storms are typically considered to enhance coastal erosion due to sea-level rise. However, they can also contribute positively to the nearshore sediment budget by exchanging sediment, potentially mitigating some adverse sea-level rise impacts. This study uses high-resolution morphological datasets from Australia, the UK, and Mexico to quantify the nearshore sediment budget and relate episodic volume changes to long-term coastal projections. Results show that sediment gains over the upper shoreface were large enough to theoretically offset decades of projected shoreline retreat due to sea-level rise, even under a high-end greenhouse gas emissions scenario. The study concludes that robust shoreline projections require a quantitative understanding of the sediment budget, including short-term sediment contributions from extreme storms.

Mitchell D. Harley, Gerd Masselink, Amaia Ruiz de Alegría-Arzaburu, Nieves G. Valiente, Tim Scott