Earth is mostly diffusive: A global analysis of landscape evolution

Earth's landscapes-from mountains to river deltas-are shaped by sediment erosion, transport, and deposition. However, most landscape evolution models represent only two processes: diffusive soil creep and bedrock river incision. How much of Earth's surface can be represented by these two processes alone? To address this question, we mapped the global abundance and distribution of eight major geomorphic process domains, finding that ~75% of Earth's land area consists of soil-mantled hillslopes and flatlands dominated by diffusive soil creep, while 0.5% is a bedrock river corridor. While other process domains (glaciers, lakes, alluvial river corridors, aeolian deserts, and bedrock hillslopes) make up only ~24% of Earth's land area, they transport most of the sediment from continents to oceans. Process domains align with different topographic, climatic, and tectonic conditions, indicating a pathway to improve coupled global landscape, climate, and tectonic evolution models. Overall, our results reveal the distribution of the eight major geomorphic process domains globally and highlight the spatial dominance of diffusive topography.