A Global Assessment of Anthropogenic Geomorphology

Human societies now act as a potent geomorphic agent that has already transformed landscapes across more than one-third of Earth’s terrestrial surface. To interpret the extent, intensity, and form of human geomorphic fingerprints across Earth’s land, it will be necessary to map and quantify distinctive anthropogenic geomorphic features at local and global scales. With the development of remote sensing techniques such as LiDAR and airborne platforms, high-resolution topography opens new avenues to a variety of terrain information. Anthropogenic feature visualization and detection are now possible. However, the proper indices to quantify surface processes pose a pivotal challenge to geomorphologists. Sofia et al. developed a geomorphological model capable of computing percentages of human-made alterations to terrain using high-resolution DTMs (Digital Terrain Models). These computations are highly dependent on the availability of fine-scale topographic data (eg. LiDAR data) which are not yet available at global scale. Nevertheless, the anthropogenic geomorphic features tend to reflect the socioeconomic and ecological patterns of human societies, so it may be possible to evaluate the topographic fingerprints of humanity based on correlations with spatial data on these patterns. we use nighttime light, terrain and land cover data to assess the socio-economic and ecological dynamics. Global maps of anthropogenic biomes (anthromes) also provide a useful classification of the globally significant patterns of human transformation of ecosystems. By combining these data, a global map of the sociocultural shapers of anthropogenic geomorphic features was prepared. Multiple study sites (10x10 km each) with different sociocultural and natural geomorphic conditions were then selected for more detailed analysis using high-resolution DTMs derived by LiDAR at 2 m resolution. The degree of anthropogenic geomorphic alteration was then assessed using the geomorphological model. Correlations between anthropogenic geomorphology and socioeconomic and ecological patterns were established. It may vary from different classes of anthromes. Based on these correlations, we have produced the first global map of anthropogenic transformation of geomorphology.