Estimates for carbon sequestration through improved practices vary considerably (Figure 3) as the understanding of the interactions and especially the knowledge of the behavior of soils is still limited. Various studies indicate theoretical potentials of 0.8 to 8 GtC per year, partially including af-/re-forestation practices, and reaching up to 10 GtC/yr of additional carbon on agricultural land41,55, while practically achievable carbon removal amounts are rather located in the lower range of 1.5 to 2.5 GtC/yr. With global carbon emissions in 2016 from fossil fuels and industry of 9.9 GtC plus 1.3 GtC due to land-use changes (such as deforestation), the potential for carbon sequestration through regenerative agricultural practices looks rather promising, although the implementation of such practices comes with different social, economic and expertise-related and other caveats. It requires funding and collaboration amongst scientists, policymakers, practitioners and multiple other stakeholders. Soil carbon sequestration has a large but not infinite sink capacity, and, importantly, is reversible through bad management. Global efforts to gradually change land use practices are difficult to implement, reducing thus the theoretical mitigation potential.
This figure is extracted from the publication "The potential of carbon sequestration in the soil" available here