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| Titel |
How robust are responses of carbon-nitrogen cycle models to increasing atmospheric [CO2] and climatic changes? |
| VerfasserIn |
Sönke Zaehle, Pierre Friedlingstein, Andrew D. Friend |
| Konferenz |
EGU General Assembly 2010
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| Medientyp |
Artikel
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| Sprache |
Englisch
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| Digitales Dokument |
PDF |
| Erschienen |
In: GRA - Volume 12 (2010) |
| Datensatznummer |
250039674
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| Zusammenfassung |
| A number of recent studies have demonstrated the importance of considering nitrogen
dynamics for projecting the responses to the terrestrial carbon cycle to increasing
atmospheric [CO2] and climatic changes [1-4]. However, there are considerable differences in
the global and regional responses of individual models concerning the strength and even the
sign of the effect of N dynamics of the dynamics of the terrestrial carbon cycle. Here, the
implications of alternative hypotheses on key nitrogen cycle characteristics that determine
vegetation responses are tested to assess the reliability of the modelled responses.
For this purpose, the terrestrial biosphere model O-CN model, derived from the
land-surface scheme ORCHIDEE of the IPSL Earth system model, is used in different
configurations, namely the elasticity of the plant’s C:N stoichiometry, and the capacity of
vegetation to increase biological nitrogen fixation as a function of N demand and C
excess.
The alternative hypotheses result in substantially different projected land C storage by the
year 2100. However, they do not prevent i) that there is a significant reduction of the net land
C storage resulting from CO2 fertilisation compared to the model version not accounting
for terrestrial N dynamics; and ii) that on the global scale the limiting effect of N
dynamics on the CO2 fertilisation response is stronger than the stimulating effect of
increased N release from soil organic matter decomposition in a future warmer
climate.
References:
1. Sokolov, A.P., et al., Consequences of considering carbon-nitrogen interactions on the
feedbacks between climate and the terrestrial carbon cycle. Journal of Climate, 2008. 21(15):
p. 3776-3796.
2. Jain, A., et al., Nitrogen attenuation of terrestrial carbon cycle response to
global environmental factors. Global Biogeochemical Cycles, 2009. 23: p. GB4028,
doi:10.1029/2009GB003519.
3. Thornton, P.E., et al., Carbon-nitrogen interactions regulate climate-carbon cycle
feedbacks: results from an atmosphere-ocean general circulation model. Biogeosciences,
2009. 6: p. 2099-2120.
4. Zaehle, S., P. Friedlingstein, and A. Friend, Terrestrial nitrogen feedbacks may
accelerate future climate change. Geophysical Research Letters, 2010. 37: p. L01401,
doi:10.1029/2009GL041345. |
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