Fluvial erosion linked to warming in the Canadian Arctic

Warming temperatures have been invoked as a potential mechanism for widespread change to the erosional regime in Arctic regions, where large portions of watersheds are underlain by permanently frozen soils. Yet recent site-specific studies have delivered conflicting results regarding how erosion along Arctic rivers has responded to past temperature increase, and how erosion will respond to rising temperatures in the future. Here we use 92,009 observations of fluvial erosion across 13,400 stream kilometers in the Mackenzie River watershed to show that erosion rates along rivers across the Canadian Arctic are positively correlated to temperature and uncorrelated with vegetative cover over the satellite record (1985-present). While temperature’s erosive effect appears to be mediated by discharge, our results nevertheless suggest warming will lead to increased erosion in the Arctic but that the enhanced erosive regime may be less dramatic than earlier predictions. Increased temperatures in the Canadian Arctic are aligned with higher fluvial erosion, although this is mediated by fluvial discharge, according to analysis of geomorphic data from the Mackenzie River watershed.