Lateral transport of soil carbon and land−atmosphere CO ₂ flux induced by water erosion in China

<jats:title>Significance</jats:title> <jats:p> The role of soil erosion as a net sink or source of atmospheric CO <jats:sub>2</jats:sub> remains highly debated. This work quantifies national-scale land−atmosphere CO <jats:sub>2</jats:sub> fluxes induced by soil erosion. Severe water erosion in China has caused displacement of 180 ± 80 Mt C⋅y <jats:sup>-1</jats:sup> of soil organic carbon during the last two decades, and the consequent land−atmosphere CO <jats:sub>2</jats:sub> flux from water erosion is a net CO <jats:sub>2</jats:sub> sink of 45 ± 25 Mt C⋅y <jats:sup>-1</jats:sup> , equivalent to 8–37% of the terrestrial carbon sink previously assessed in China. This closes an important gap concerning large-scale estimation of lateral and vertical CO <jats:sub>2</jats:sub> fluxes from water erosion and highlights the importance of reducing uncertainty in assessing terrestrial carbon balance. </jats:p>