A tale of two scales, or the two geomorphologies

Since the 1960s the analysis of small-scale surface processes has been the dominant approach in geomorphology, the previous focus on regional-scale landscape evolution having been largely abandoned as a result of the lack of knowledge of processes and process rates at the relevant temporal and spatial scales. It has recently been acknowledged that small-scale, surface process geomorphology alone is unable to provide an understanding of long-term landscape development, both because of the significance of tectonics, and because of the important role of contingency at the large temporal and spatial scales involved. But the major advances in geochronological techniques and numerical modelling of landscape evolution that are now revolutionizing our understanding of long-standing questions of landscape evolution have been largely developed and applied by researchers from outside the traditional geomorphology community. As a result, two distinct communities of researchers have emerged concerned with different scales of landform analysis, but the progress of geomorphology will be best served by greater interaction between them.