Lateral carbon transfer from erosion in noncroplands matters

This study combines two unprecedentedly high resolution (250 × 250 m) maps of soil erosion (inter‐rill and rill processes) and soil organic carbon to calculate a global estimate of erosion‐induced organic carbon (C) displacement. The results indicate a gross C displacement by soil erosion of urn:x-wiley:13541013:media:gcb14125:gcb14125-math-0001 Pg C/year. The greatest share of displaced C (64%) comes from seminatural lands and forests. This suggests that lateral C transfer from erosion in noncroplands may play a more important role than previously assumed. Human civilization has increasingly exploited land and soil for millennia. Today, undisturbed primary vegetation is at its historical minimum with agricultural areas covering about 38% of the Earth's ice‐free land surface (Foley et al., 2011; 12% croplands and 26% pastures). The anthropogenic acceleration of soil erosion and the impacts on soil quality are well‐known (Dotterweich, 2008; García‐Ruiz et al., 2015). Impacts on climate change, however, remain uncertain and contested, due to the extent to which soil erosion increases or decreases CO2 emissions. The extent to which eroded SOC is mineralized or buried in sediment is hotly debated (Lal, 2004; Van Oost et al., 2007). In their recent publication, Wang et al. (2017) introduced new analysis in support of the erosion‐induced C sink theory, suggesting that anthropogenic acceleration of soil erosion over the last 8,000 years would have had the potential to offset 37 ± 10% of previously recognized C emissions resulting from anthropogenic land cover change.