Abstract

Ask any geomorphologist about the effect of climate change on river systems, and you’ll soon be deep in a conversation about valleys, terraces, sediment supply, floods, and the forces that climate change can exert on the fluvial system. Mention rivers to global climate scientists, and you may hear how changing patterns of freshwater discharge to the ocean through the global river networks can drastically affect ocean circulation and global climate. These two links between the fluvial and climate systems, in which they each have their turn in the driver’s seat, are often investigated in isolation by practitioners of these two subfields within Earth Sciences. In my talk, I will link them through three vignettes. First, I will present how ice-sheet advance and retreat rerouted rivers across North America (and the globe), changing positions of meltwater discharge to the sea, and therefore impacting the climate that fed back into the ice sheets and rivers. Second, I will zoom in on the Mississippi River, whose modern form was created by the ice sheets, and still aggrades and incises with the pulse of ice-sheet advance and retreat and meltwater delivery to the Atlantic. Finally, I will demonstrate that the width-evolution of alluvial rivers may cause different systems to evolve along divergent paths, with the Upper Mississippi and the Quebrada del Toro, Argentina, as both inspiration and study sites for hypothesis testing.