Soil Organic Carbon Erosion is Critical for Land Degradation Neutrality

TitleSoil Organic Carbon Erosion is Critical for Land Degradation Neutrality
Publication TypeJournal Article
Year of Publication2019
AuthorsChappell A., Webb N, Leys J, Waters C, Orgill S, Eyres M
JournalEnvironmental Science and Policy
Start Page43
Date Published03/2019
ARIS Log Number353488
Keywordsland cover, land degradation neutrality, sequestration, soil organic carbon, wind erosion

The Land Degradation-Neutrality (LDN) framework of the United Nations Convention to Combat Desertification (UNCCD) is underpinned by three complementary interactive indicators (metrics: vegetation cover, net primary productivity; NPP and soil organic carbon; SOC) as proxies for change in the land-based natural capital. The LDN framework assumes that SOC changes slowly primarily by decomposition and respiration of CO2 to the atmosphere. However, we show there is growing evidence that SOC erosion also reduces SOC stocks and rapidly after land use / cover change. Here we use a physically-based model to quantify global SOC erosion by wind (2001-2010) and identify global dryland regions where SOC erosion may be a significant problem for achieving LDN. Selected sites in global drylands show SOC erosion accelerating over time. Without targeting and reducing SOC erosion, management practices will fail to sequester SOC and reduce land degradation, thereby undermining the LDN framework. We describe the interrelated nature of the LDN indicators, the importance of including SOC erosion and how land cover can be replaced by erosion that better represents the physical effects of land cover on land degradation processes. Therefore, we call for SOC erosion to become an LDN indicator. Furthermore, our results suggest that fluxes of SOC and soil nutrients by soil erosion should be emphasised in the forthcoming Intergovernmental Panel on Climate Change (IPCC) Special Report on climate change, desertification, land degradation, sustainable land management, food security, and greenhouse gas fluxes in terrestrial ecosystems.