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| Titel |
Changes in soil organic carbon storage predicted by Earth system models during the 21st century |
| VerfasserIn |
K. E. O. Todd-Brown, J. T. Randerson, F. Hopkins, V. Arora, T. Hajima, C. Jones, E. Shevliakova, J. Tjiputra, E. Volodin, T. Wu, Q. Zhang, S. D. Allison |
| Medientyp |
Artikel
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| Sprache |
Englisch
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| ISSN |
1726-4170
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| Digitales Dokument |
URL |
| Erschienen |
In: Biogeosciences ; 11, no. 8 ; Nr. 11, no. 8 (2014-04-25), S.2341-2356 |
| Datensatznummer |
250117378
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| Publikation (Nr.) |
 copernicus.org/bg-11-2341-2014.pdf |
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| Zusammenfassung |
| Soil is currently thought to be a sink for carbon; however, the response of
this sink to increasing levels of atmospheric carbon dioxide and climate
change is uncertain. In this study, we analyzed soil organic carbon (SOC)
changes from 11 Earth system models (ESMs) contributing simulations to the
Coupled Model Intercomparison Project Phase 5 (CMIP5). We used a reduced
complexity model based on temperature and moisture sensitivities to analyze
the drivers of SOC change for the historical and high radiative forcing (RCP
8.5) scenarios between 1850 and 2100. ESM estimates of SOC changed over the
21st century (2090–2099 minus 1997–2006) ranging from a loss of 72 Pg C to
a gain of 253 Pg C with a multi-model mean gain of 65 Pg C. Many ESMs
simulated large changes in high-latitude SOC that ranged from losses of
37 Pg C to gains of 146 Pg C with a multi-model mean gain of 39 Pg C
across tundra and boreal biomes. All ESMs showed cumulative increases in
global NPP (11 to 59%) and decreases in SOC turnover times (15 to
28%) over the 21st century. Most of the model-to-model variation in SOC
change was explained by initial SOC stocks combined with the relative changes
in soil inputs and decomposition rates (R2 = 0.89, p < 0.01). Between
models, increases in decomposition rate were well explained by a combination
of initial decomposition rate, ESM-specific Q10-factors, and changes in
soil temperature (R2 = 0.80, p < 0.01). All SOC changes depended on
sustained increases in NPP with global change (primarily driven by increasing
CO2). Many ESMs simulated large accumulations of SOC in high-latitude
biomes that are not consistent with empirical studies. Most ESMs poorly
represented permafrost dynamics and omitted potential constraints on SOC
storage, such as priming effects, nutrient availability, mineral surface
stabilization, and aggregate formation. Future models that represent these
constraints are likely to estimate smaller increases in SOC storage over the
21st century. |
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