The age distribution of global soil carbon inferred from radiocarbon measurements

ABSTRACT Soils contain more carbon than the atmosphere and vegetation combined. An increased flow of carbon from the atmosphere into soil pools could help mitigate anthropogenic emissions of

carbon dioxide and climate change. Yet we do not know how quickly soils might respond because the age distribution of soil carbon is uncertain. Here we used 789 radiocarbon (∆14C) profiles,

along with other geospatial information, to create globally gridded datasets of mineral soil ∆14C and mean age. We found that soil depth is a primary driver of ∆14C, whereas climate (for

example, mean annual temperature) is a major control on the spatial pattern of ∆14C in surface soil. Integrated to a depth of 1 m, global soil carbon has a mean age of 4,830 ± 1,730 yr, with

older carbon in deeper layers and permafrost regions. In contrast, vertically resolved land models simulate ∆14C values that imply younger carbon ages and a more rapid carbon turnover. Our

data-derived estimates of older mean soil carbon age suggest that soils will accumulate less carbon than predicted by current Earth system models over the twenty-first century. Reconciling

these models with the global distribution of soil radiocarbon will require a better representation of the mechanisms that control carbon persistence in soils. Access through your institution

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ADDITIONAL ACCESS OPTIONS: * Log in * Learn about institutional subscriptions * Read our FAQs * Contact customer support SIMILAR CONTENT BEING VIEWED BY OTHERS PROJECTED SOIL CARBON LOSS

WITH WARMING IN CONSTRAINED EARTH SYSTEM MODELS Article Open access 02 January 2024 A SPATIAL EMERGENT CONSTRAINT ON THE SENSITIVITY OF SOIL CARBON TURNOVER TO GLOBAL WARMING Article Open

access 02 November 2020 GLOBAL SOIL PROFILES INDICATE DEPTH-DEPENDENT SOIL CARBON LOSSES UNDER A WARMER CLIMATE Article Open access 20 September 2022 DATA AVAILABILITY The gridded maps of

soil ∆14C and MCA are archived at Zenodo (https://doi.org/10.5281/zenodo.3823612). Other data that support the findings of this study are publicly available. Soil ∆14C measurements are

available at https://zenodo.org/record/2613911#.XsNtQi-z124. Global soil carbon and soil clay content in SoilGrids are available at https://landgis.opengeohub.org. Soil carbon content in

HWSD is available at https://go.nature.com/2ASmPC3. Global soil order data are available at https://go.nature.com/3hgdsgb. The climate data used can be downloaded from

https://crudata.uea.ac.uk/cru/data/hrg/. The land cover map can be obtained from the MODIS Land cover MCD12Q1 product (https://lpdaac.usgs.gov/products/mcd12q1v006/). The permafrost map was

generated by the National Snow and Ice Data Center (https://go.nature.com/2AZbTTe). CODE AVAILABILITY All code relating to this study is available from the corresponding author upon request.

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(2016). Google Scholar  Download references ACKNOWLEDGEMENTS This work was supported by the European Research Council (Horizon 2020 Research and Innovation Programme, grant agreement 695101,

to S.T. and J.T.R.), by the US DOE Office of Science Biological and Environmental Research RUBISCO Science Focus Area (to J.T.R. and Q.Z.) and award DE-SC0014374 (to S.D.A. and J.T.R.) and

by a NASA Earth and Space Science Fellowship (to P.A.L.). AUTHOR INFORMATION AUTHORS AND AFFILIATIONS * Department of Ecology and Evolutionary Biology, University of California Irvine,

Irvine, CA, USA Zheng Shi & Steven D. Allison * Department of Earth System Science, University of California Irvine, Irvine, CA, USA Zheng Shi, Steven D. Allison, Yujie He, Paul A.

Levine & James T. Randerson * Department of Biogeochemical Processes, Max-Planck-Institute for Biogeochemistry, Jena, Germany Alison M. Hoyt, Jeffrey Beem-Miller & Susan Trumbore *

Climate and Ecosystem Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, CA, USA Qing Zhu * Climate and Global Dynamics Laboratory, National Center for Atmospheric Research,

Boulder, CO, USA William R. Wieder Authors * Zheng Shi View author publications You can also search for this author inPubMed Google Scholar * Steven D. Allison View author publications You

can also search for this author inPubMed Google Scholar * Yujie He View author publications You can also search for this author inPubMed Google Scholar * Paul A. Levine View author

publications You can also search for this author inPubMed Google Scholar * Alison M. Hoyt View author publications You can also search for this author inPubMed Google Scholar * Jeffrey

Beem-Miller View author publications You can also search for this author inPubMed Google Scholar * Qing Zhu View author publications You can also search for this author inPubMed Google

Scholar * William R. Wieder View author publications You can also search for this author inPubMed Google Scholar * Susan Trumbore View author publications You can also search for this author

inPubMed Google Scholar * James T. Randerson View author publications You can also search for this author inPubMed Google Scholar CONTRIBUTIONS Z.S., Y.H., S.D.A., S.T. and J.T.R. designed

the study; Z.S. and Y.H. analysed the data using machine learning and other approaches; P.A.L., W.R.W. and Q.Z. provided analysis of the land surface models; J.B.-M., A.M.H., P.A.L. and S.T.

contributed to the development of the version of the ISRaD dataset used here; Z.S., S.D.A. and J.T.R. wrote the paper with substantial contributions from all of the authors. CORRESPONDING

AUTHOR Correspondence to Zheng Shi. ETHICS DECLARATIONS COMPETING INTERESTS The authors declare no competing interests. ADDITIONAL INFORMATION PEER REVIEW INFORMATION Primary Handling

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SUPPLEMENTARY INFORMATION Supplementary Figs. 1–17 and Tables 1–5. RIGHTS AND PERMISSIONS Reprints and permissions ABOUT THIS ARTICLE CITE THIS ARTICLE Shi, Z., Allison, S.D., He, Y. _et

al._ The age distribution of global soil carbon inferred from radiocarbon measurements. _Nat. Geosci._ 13, 555–559 (2020). https://doi.org/10.1038/s41561-020-0596-z Download citation *

Received: 15 January 2020 * Accepted: 19 May 2020 * Published: 29 June 2020 * Issue Date: August 2020 * DOI: https://doi.org/10.1038/s41561-020-0596-z SHARE THIS ARTICLE Anyone you share the

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