The Impacts of Erosion on the Carbon Cycle

Physical and chemical erosion associated with water both affect land-atmosphere carbon exchanges. However, previous studies have often addressed these processes separately or used oversimplified mechanisms, leading to ongoing debates and uncertainties about erosion-induced carbon fluxes. We provide an overview of the on-site carbon uptake fluxes induced by physical erosion (0.05-0.29 Pg C yr-1, globally) and chemical erosion (0.26-0.48 Pg C yr-1). Then, we discuss off-site carbon dynamics (during transport, deposition, and burial). Soil organic carbon mineralization during transport is nearly 0.37-1.20 Pg C yr-1 on the globe. We also summarize the overall carbon fluxes into estuaries (0.71-1.06 Pg C yr-1) and identify the sources of different types of carbon within them, most of which are associated with land erosion. Current approaches for quantifying physical-erosion-induced vertical carbon fluxes focus on two distinct temporal scales: short-term dynamics (ranging from minutes to decades), emphasizing net vertical carbon flux, and long-term dynamics (spanning millennial to geological timescales), examining the fate of eroded carbon over extended periods. In addition to direct chemical measurement and modeling approaches, estimation using indicators of riverine material is popular for constraining chemical-erosion-driven carbon fluxes. Lastly, we highlight the key challenges for quantifying related fluxes. To overcome potential biases in future studies, we strongly recommend integrated research that addresses both physical and chemical erosion over a well-defined timescale. A comprehensive understanding of the mechanisms driving erosion-induced lateral and vertical carbon fluxes is crucial for closing the global carbon budget.