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The steep topography of mountain landscapes arises from interactions between tectonic rock uplift, valley incision and landslide erosion on hillslopes. An analysis of more than 15,000 landslides in the eastern Himalaya, mapped from satellite images, shows that steep uplands primarily respond to uplift and river incision by increases in landslide erosion rates rather than by steepened hillslope angles.

It has been debated whether rivers or glaciers are more effective agents of erosion. A global compilation of erosion rates reveals that both are capable of generating rates of erosion that match or exceed the highest rates of rock uplift. Since the late nineteenth century, it has been debated whether rivers or glaciers are more effective agents of erosion1. The dramatic landscapes associated with glaciated terrain have often led to the argument that glaciers are more erosive than rivers, and recent studies have documented the topographic signature of an ice-controlled limit of mountain height known as the ‘glacial buzz-saw’2,3. Here we present a new global compilation of erosion rates, which questions the conventional view of glaciers and erosion. In regions of rapid tectonic uplift, erosion rates from rivers and glaciers both range from 1 to over 10 mm yr−1, indicating that both are capable of generating erosion rates matching or exceeding the highest rates of rock uplift. Moreover, a comparison of erosion rates over timescales ranging from 101 to 107 years indicates that glacial erosion tends to decrease by one to two orders of magnitude over glacial cycles, whereas fluvial erosion rates show no apparent dependence on time. We conclude that tectonics controls rates of both fluvial and glacial erosion over millennial and longer timescales and that the highest rates of erosion (>10 mm yr−1) generally result from a transient response to disturbance by volcanic eruptions, climate change and modern agriculture.

The St Elias orogen in Alaska is one of the world’s highest coastal mountain ranges. An age analysis of detrital material in active sediment systems in the inaccessible ice-covered valley bottoms reveals localized exhumation that is driven by coupling between erosion and active tectonic rock uplift.

Simple physical arguments, analogue experiments and numerical experiments all suggest that the internal dynamics of actively deforming collisional mountain ranges are influenced by climate. However, obtaining definitive field evidence of a significant impact of climate on mountain building has proved challenging. Spatial correlations between intense precipitation or glaciation and zones of rapid rock-uplift have indeed been documented in numerous mountain ranges, and are consistent with model predictions. More compelling evidence — such as tectonic changes in response to (rather than just coincident with) climate change — has, however, rarely been documented. Triggered by a climate-driven increase in erosion rate, friction-dominated mountain ranges are expected to show a number of simultaneous responses: a decrease in the width of the range, a temporary increase in sediment yield, a persistent increase in the rate of rock uplift and a reduction in the subsidence rate of surrounding basins. The most convincing field evidence for such a coordinated response of a mountain range to climate change comes from the European Alps and the St Elias range of Alaska. Field studies and experimental research during the past two decades have provided considerable evidence for a significant influence of climate on tectonics. Recent advances suggest that model predictions can guide future fieldwork aimed at substantiating this view.

The interactions between climate and tectonics in active mountain ranges are complex and important. Field and geophysical data from the St Elias Range of Alaska show that glacial erosion can influence the dynamics of the lithosphere in such settings.