Radiocarbon constraints imply reduced carbon uptake by soils during the 21st century
- Author(s): He, Y
- Trumbore, SE
- Torn, MS
- Harden, JW
- Vaughn, LJS
- Allison, SD
- Randerson, JT
- et al.
Published Web Locationhttps://doi.org/10.1126/science.aad4273
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 used14C data from157 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 arbon 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.
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