Radiocarbon constraints imply reduced carbon uptake by soils during the 21st century

Yujie He; Susan E Trumbore; Margaret S Torn; Jennifer W Harden; Lydia J S Vaughn; Steven D Allison; James T Randerson

doi:10.1126/science.aad4273

Radiocarbon constraints imply reduced carbon uptake by soils during the 21st century

Science. 2016 Sep 23;353(6306):1419-1424. doi: 10.1126/science.aad4273.

Authors

Yujie He¹, Susan E Trumbore², Margaret S Torn³, Jennifer W Harden⁴, Lydia J S Vaughn³, Steven D Allison⁵, James T Randerson⁶

Affiliations

¹ Department of Earth System Science, University of California, Irvine, CA, USA. yujie.he@uci.edu.
² Department of Biogeochemical Processes, Max-Planck-Institute for Biogeochemistry, Jena, Germany.
³ Earth Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, CA, USA.
⁴ U.S. Geological Survey, Menlo Park, CA, USA. Stanford University, Stanford, CA, USA.
⁵ Department of Earth System Science, University of California, Irvine, CA, USA. Department of Ecology and Evolutionary Biology, University of California Irvine, Irvine, CA, USA.
⁶ Department of Earth System Science, University of California, Irvine, CA, USA.

PMID: 27708036
DOI: 10.1126/science.aad4273

Abstract

Soil is the largest terrestrial carbon reservoir and may influence the sign and magnitude of carbon cycle-climate feedbacks. Many Earth system models (ESMs) estimate a significant soil carbon sink by 2100, yet the underlying carbon dynamics determining this response have not been systematically tested against observations. We used ¹⁴C data from 157 globally distributed soil profiles sampled to 1-meter depth to show that ESMs underestimated the mean age of soil carbon by a factor of more than six (430 ± 50 years versus 3100 ± 1800 years). Consequently, ESMs overestimated the carbon sequestration potential of soils by a factor of nearly two (40 ± 27%). These inconsistencies suggest that ESMs must better represent carbon stabilization processes and the turnover time of slow and passive reservoirs when simulating future atmospheric carbon dioxide dynamics.

Publication types

Research Support, U.S. Gov't, Non-P.H.S.