Increased Subglacial Sediment Discharge in a Warming Climate: Consideration of Ice Dynamics, Glacial Erosion, and Fluvial Sediment Transport

Abstract

AbstractWe evaluate changes to subglacial sediment discharge during glacier retreat by considering ice dynamics, bedrock erosion, and sediment transport processes. Coupling these components together within a single framework, we simulate sediment discharge from synthetic alpine glaciers experiencing accelerated glacier melt for 100 years. We find that sediment discharge increases by about 8 times the steady glacier values by the end of the simulation. The enhanced sediment discharge persists through peak water discharge and despite annual bedrock erosion volume decreasing by approximately 30% from the initial value. The greater sediment discharge results from increased melt at the glaciers' higher region, where transport was limited prior to glacier retreat. These findings suggest that large increases in sediment discharge may occur as glaciers retreat. The magnitude of the sediment discharge increase primarily depends on the quantity of sediment stored subglacially.