Human-driven global geomorphic change

Abstract

We synthesize evidence suggesting a chain of global cause-effect relationships, linking population and economic development with cumulative effects on changes in landscape dynamics, including denudation and sediment transport/deposition. Temporal trends in global patterns of geomorphic processes or process combinations such as denudation, sedimentation, or frequency of geomorphic disasters, appear to reflect growing human pressure. Erosion rates, intensified by anthropogenic factors, are currently one to two orders of magnitude greater than prior to the 20th century, and are growing further. Per capita human transfer of Earth materials has increased tenfold. A considerable increase in the frequency of disasters related to geomorphic processes has also taken place in just over half a century, outpacing changes in other natural disasters. It is especially significant that the ratio between the frequency of geomorphic (implying water/land interaction, obviously influenced by climate change) disasters and frequency of purely climate-related disasters has increased more than ten-fold since the early 20th century. The changes described in geomorphic processes (global geomorphic change) appear to respond mainly to land surface modification, which reflects a “Great Geomorphic Acceleration” after the mid-twentieth century. However, these stressors, characteristic of the “Anthropocene”, likely interact with climate change, increasing concerns about future implications for Earth surface dynamics and underscoring the need to not only reduce GHG emissions, but also improve land use practices, which modify the conditions of the terrain.