Projections of global delta land loss from sea-level rise in the 21st century

Jaap H. Nienhuis

River deltas will likely experience significant land loss because of relative sea-level rise (RSLR), but predictions have not been tested against observations. Here, we use global data of RSLR and river sediment supply to build a model of delta response to RSLR for 6,402 deltas, representing 86% of global delta land. We validate this model against delta land area change observations from 1985-2015, and project future land area change for IPCC RSLR scenarios. For 2100, we find widely ranging delta scenarios, from +94 ± 125 (2 s.d.) km2 yr-1 for RCP2.6 to -1026 ± 281 km2 yr-1 for RCP8.5. River dams, subsidence, and sea-level rise have had a comparable influence on reduced delta growth over the past decades, but if we follow RCP8.5 to 2100, more than 85% of delta land loss will be caused by climate-change driven sea-level rise, resulting in a loss of ~5% of global delta land.