Global soil organic carbon estimates and the Harmonized World Soil Database

Hiederer, R. and Köchy, M. (2011)

Global estimates of soil organic carbon stocks have been produced in the past to support the calculation of potential emissions of CO2 from the soil under scenarios of change land use/cover and climatic conditions (IPCC, 2006), but very few global estimates are presented as spatial data. For global spatial layers on soil parameters, the most recent and complete dataset is available as the Harmonized World Soil Database (HWSD). The HWSD represents a step forward towards a spatially more detailed and thematically more refined set of global soil data.

During the evaluation of the data for generating estimates of global SOC stocks Version 1.1 of the HWSD revealed also some rough edges. Consequential are the values of bulk density attributed to soils high in organic carbon. In the evaluation the database was completed and suitable substitutions for bulk density for soil high in organic carbon were investigated. For the amended data the global SOC stock to 100cm soil depth is estimated at 1'417 Pg C, although this estimate very much dependent on the ancillary data used.

The amended HWSD was compared to data from 4 other global data sets on SOC stocks. The comparative evaluation has demonstrated that bulk density is the most important factor for estimating SOC stocks and mainly responsible for the differences between estimates. Most affected from the variability in bulk density are SOC stocks in areas with soils which are high in organic carbon.

Full Text: JRC Scientific and Technical Reports 68528

[Image and text copied from JRC Landmanagement and Natural Hazards, 2012-04-02, with permission]

You will find the organic carbon density (t ha-1) for the topsoil (0 – 30cm) and the subsoil layer (30 – 100cm) from the amended HWSD. The Global Soil Organic Carbon estimates are available in 2 different grid resolutions (ZIP compression):

The data are in Idrisi format. They are freely available upon request: Fill this online form ; after which you will be provided with instructions on how to download the data.

Download the Report Global Soil Organic Carbon Estimates and the Harmonized World Soil Database R. Hiederer, M. Köchy 2012, 79 pp., EUR 25225 EN, EUR Scientific and Technical Research series. ISSN 1831-9424 (online), ISSN 1018-5593 (print), ISBN 978-92-79-23108-7, doi:10.2788/13267