A review on the possible factors influencing soil inorganic carbon under elevated CO2

Abstract Soil inorganic carbon (SIC) is the largest pool (≈950 Pg of soil carbonate + 1404 Pg of bicarbonate in groundwater; i.e., 1 Pg = 1015 g = 1 gigaton) of the global carbon cycle at a 100 cm depth, and it might be a significant carbon source and sink in arid and semi-arid regions. The knowledge of the impacts of changing climatic conditions on this important soil structural component is minimal. This review paper provides an inclusive compilation of the available information on potential natural and anthropogenic factors triggering soil acidification and weathering mechanisms under elevated CO2. Furthermore, the consequences of elevated atmospheric CO2 on the SIC pool, soil quality, and compromised ecosystem services have been explored. Soil water content and precipitation are critical factors that influence the effects of elevated CO2 in the SIC pool. Soil microbiological properties, respiration, depth, weathering, precipitation, acidity, and fertilization are emphasized here owing to the high degree of interrelationship between these factors on influencing overall soil quality. These phenomena are then outlined together with comments about possible short and long-term consequences in SIC stock.