Predicting Coastal Deltaic Change on a Global Scale

Coastal deltaic change is expected to be one of the major Earth-surface hazards of the 21st century as deltas around the world face large changes in sediment supply due to river damming, land-use changes and climate change. We have combined estimates of present and future sediment delivery and wave climates to predict the future morphologic response of deltaic coastlines worldwide. Simple parameterizations and key insights from coastline evolution models have allowed us to make morphologic predictions around the globe for every delta on Earth. We find that without human interference many deltas with decreased sediment loads are expected to be reworked by waves into spits and barrier islands. Other deltas are projected to experience increased sediment flux, and, in some cases these growing deltas could transition from wave-dominated to river-dominated morphologies. This unified, global picture of future deltaic change will aid local management of deltaic areas and also provide opportunities for inclusion of morphologic change into Climate and Earth System Models.