It’s mainly stored in forest soils. Human activities, such as agriculture, or natural hazards, such as flooding, landslides, erosion, but also deforestation, biomass burning, environmental pollution, can alter its balance. Its content is related to soil type and land cover / use while having a great global mitigation potential, both in terms of carbon sinks and reduced carbon emissions. It’s the soil organic carbon (SOC) and given the current climate change, an accurate knowledge about its quantity is a key factor: a net carbon loss from soils adds in fact to the increase in the atmospheric CO2 concentration, probably leading to higher global temperatures, which, in turn, could accelerate decomposition of SOC. On the other hand, a net soil CO2 sequestration could help to mitigate the greenhouse effect and to improve soil quality.
The report ” Global Soil Organic Carbon Database (at 30 arcsec)“
realized by FAO and the CMCC Foundation in the framework of the GEOCARBON project
provides an implemented version of the Global Soil Organic Carbon database while trying to identifying areas suitable to reduce emissions through SOC sequestration.
With this updated database, the final map of Soil Organic Carbon stock has been raised to a resolution of approximately1 km at the Equator (30 arcsec). “In addition to the produced maps”, Sergio Noce, researcher at the CMCC Foundation and one of the lead authors of the report with CMCC researcher Tommaso Chiti (other CMCC researchers involved in the study are Monia Santini and Antonio Bombelli) says, “the soil organic carbon stock database was largely incremented compared to the previous versions of the database, with the addition of about 8000 georeferenced soil profiles, covering the African continent, where there was a lack of information. The final global database contains a set of nearly 24 000 georeferenced soil profiles derived from many sources, and report the SOC stock associated to each single profile for two reference depths: 0-30 and 30-100 cm”.
More in detail, S. Noce implemented the methodologies and approaches used, that is Geographic Information Systems (GIS) software for spatial data analyses. The global database on SOC stock provides data on soil features, SOC stock for the 0-30 and 30-100 cm depth of mineral soil and general information on the vegetation and land use for each single profile, such as croplands, grasslands, tree covered areas, herbaceous vegetation, bare soils, artificial surfaces, etc.
Results highlighted that most of the SOC is stored in the topsoil and mainly in forests. “Other geodatabases were already realized by other studies”, Sergio Noce says, “but the added value of our global database map is its finer resolution covering approximately all Earth land surface and all terrestrial ecosystems. The work used the main soil organic carbon databases available and was enriched with the addition of data never published before such those contained in the databases provided by the University of Tuscia and FAO, related to soil profiles mostly located in Europe and Africa. Therefore the preliminary harmonization effort of a great amount of soil profiles (realized by T.Chiti) and the realization of global high resolution maps are the main important aspects of our work”.
The availability of high resolution maps will provide an indication at global and regional levels, useful to support C budgets and evaluations, and a considerable support to policy makers in land management and planning activities.
“The next step”, S. Noce concludes, “could be the use of climate change scenarios in identifying terrestrial ecosystems while trying to detect future potential changes”.