Global Soil Inorganic Carbon Database

Data repository for the paper "Size, distribution and vulnerability of the global soil inorganic carbon (Huang et al. 2024, Science, DOI: 10.1126/science.adi7918)". The global soil inorganic carbon (SIC) database provides high-resolution (30 arc-seconds) global gridded SIC data for three soil depths (0-30cm, 30-100cm, 100-200cm). SIC is expressed as carbonate equivalent in fine earth (i.e., ≤ 2 mm), in unit of gC/kg(soil).

This dataset includes six gridded data files in NetCDF format. Three files provide the estimations of present-day SIC for three soil depths. The other three files contain values of the standard deviations of each estimation based on machine learning models built during 10-fold cross validation. These data are generated through linking measured SIC content (N > 200,000) to spatially explicit environment covariates by using the machine learning models (two-part models: binary classification and regression model) (Materials and Methods).

There are two csv files documenting the compiled measured SIC at different locations across the globe. Site-level measurements were collected from the ISRIC World Soil Information Service (WoSIS) with standardised soil profile data, supplemented by additional databases from National Soil Surveys, resamplings and new measurements from China, from literature via “China National Knowledge Infrastructure” (https://www.cnki.net/) and “Web of Science” (http://www.isiknowledge.com/), from additional samples collected in South-West Germany, Egypt and Russia. University of Hohenheim holds the ownership of the measured data with the label "Germany_xxx". A small portion of entries of measured samples located in northeast China are left empty due to data sharing policies. For users need this part of data, please address to Dr. Songbai Hong (songbaih@pku.edu.cn). The gridded NetCDF data is likely to be less accurate in observation limited regions compared to regions with enough measurements. Caution is advised when applying this data in such areas. Variable names follow the conventions used in WoSIS snapshot - September 2019. The study of "Significant loss of soil inorganic carbon at the continental scale" (National Science Review, Volume 9, Issue 2, February 2022, nwab120) and Supplementary Table S12 provide literature lists from which additional measurements were extracted.

This archive also hosts programming codes for reading compiled data, training predictive models, generating NetCDF files or creating visual displays.