Accelerated soil erosion is primarily driven by modifications in land use and management. GLASOD and its successor GLADIS 24 provided insights into soil erosion based on a static observation approach but did not quantify the effects driven by changes in land use. A lack of reliable global erosion estimates forces the scientific community to resort to these pioneering studies carried out during the late 1980s and early 1990s such as UNEP’s project Global Assessment of Soil Degradation (GLASOD) 5. This soil erosion estimate dates back to 1993, first reported by Myers 21 and cited by several succeeding studies 19, 22, 23. The FAO led Global Soil Partnership 20 reports that 75 billion tonnes (Pg) of soil are eroded every year from arable lands worldwide, which equates to an estimated financial loss of US$400 billion per year.
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Sustainable governance of soil has therefore become a topic of fundamental importance 19. Feeding Earth’s growing population with increasing dietary preferences towards livestock products is undoubtedly enhancing the pressure on fertile soils 18 thus exacerbating the erosion problem. The 13% increase in production rates for the most common crops 15 between 20, due to technological improvements, more rigorous land management 16 and an increased use of fertilizer 17, might have masked the ongoing degradation of soils and their ecosystem service delivery capacity. The fear of soil erosion, especially the associated removal of the most fertile soil layer as a prelude to mass starvation has been revised lately 14. The impact on climate through erosion-induced changes in soil carbon cycling also remains poorly quantified, as erosion can both increase or decrease CO 2 emissions through enhanced mineralization and sediment burial 12, 13. Impacts can be severe, not only through land degradation and fertility loss, but through a conspicuous number of off-site effects (e.g., sedimentation, siltation and eutrophication of water ways or enhanced flooding 11). The harmful impacts of accelerated soil erosion processes caused by deforestation, overgrazing 7, tillage and unsuitable agricultural practices 8 are well-known and documented, as are its mechanics 9, 10. This is in line with previous assessments 5, 6. The results of the meta-analysis reported in this document indicate that accelerated soil erosion is a major threat to soil. The latest reference document of the United Nations (UN) on the status of global soil resources stresses that ‘…the majority of the world’s soil resources are in only fair, poor or very poor condition’ 4. It is a vital part of ecosystems and earth system functions that support the delivery of primary ecosystem services 2, 3. Healthy soil is the foundation of agriculture and an essential resource to ensure human needs in the 21st century 1, such as food, feed, fibre, clean water and clean air. The least developed economies have been found to experience the highest estimates of soil erosion rates.
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The greatest increases are predicted to occur in Sub-Saharan Africa, South America and Southeast Asia. Our findings indicate a potential overall increase in global soil erosion driven by cropland expansion. Moreover, we estimate the spatial and temporal effects of land use change between 20 and the potential offset of the global application of conservation practices. We challenge the previous annual soil erosion reference values as our estimate, of 35.9 Pg yr −1 of soil eroded in 2012, is at least two times lower. Here we present an unprecedentedly high resolution (250 × 250 m) global potential soil erosion model, using a combination of remote sensing, GIS modelling and census data.
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Human activity and related land use change are the primary cause of accelerated soil erosion, which has substantial implications for nutrient and carbon cycling, land productivity and in turn, worldwide socio-economic conditions.