Assessment of the Carbon Content in Agricultural Soils of the European Russia for Climate Projects

Soils and their organic carbon (SOC) are recognized as the main regulators of the global carbon cycle. At the same time, the calculations of SOC stock are not considered for climate projects and remain unclaimed. The aim of the study is to demonstrate the perspective of SOC stock analysis for planning and decision-making within the framework of Land Use, Land-Use Change and Forestry Programs. The study exploits modern available digital soil databases processed by QGIS tools. Using the example of agricultural soils in European Russia, it has been shown that SOC reserves in the 0.3 m layer of the base year 1990 were 7.0 Gt C in arable and 3.1 Gt C in pasture lands. It was found that during the period of agricultural use, the stock of SOC decreased by 1.8 Gt C (21% of the original content) on arable land and 0.3 Gt C (9% of the original content) on pastures. The loss of SOC stock from 0.3 m layer amounted to about 2.1 Gt C (some 7.7 Gt CO2-eq.). The decline of SOС stock from the 0.3–1.0 m layer of arable and pasture lands amounted to about 1.4 Gt C or 5.2 Gt CO2-eq., which reaches almost 70% of the loss of the surface 0.3 m layer. The total loss of SOC stock from agricultural soils from a 1.0 m layer is about 12.9 Gt CO2-eq., which is almost 9 times higher than the total greenhouse gas emission of the Russian Federation in 2020. It is proposed to include deeper layers of agricultural soils in the national standard for emissions and removals of greenhouse gas accounting. An approach is shown to use the spatial distribution of SOC stock for preliminary planning of climate projects within the framework of Land Use, Land-Use Change and Forestry Programs. For the practical establishment of greenhouse gas absorption projects, detailed justifications are required. The performed studies are harmonized with the requirements of the Intergovernmental Panel on Climate Change, which confirms the potential of soils use in climate projects of the Russian Federation.