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| Titel |
Role of volcanic forcing on future global carbon cycle |
| VerfasserIn |
J. F. Tjiputra, O. H. Otterå |
| Medientyp |
Artikel
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| Sprache |
Englisch
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| ISSN |
2190-4979
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| Digitales Dokument |
URL |
| Erschienen |
In: Earth System Dynamics ; 2, no. 1 ; Nr. 2, no. 1 (2011-06-16), S.53-67 |
| Datensatznummer |
250000460
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| Publikation (Nr.) |
 copernicus.org/esd-2-53-2011.pdf |
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| Zusammenfassung |
| Using a fully coupled global climate-carbon cycle model, we assess the
potential role of volcanic eruptions on future projection of climate change
and its associated carbon cycle feedback. The volcanic-like forcings are
applied together with a business-as-usual IPCC-A2 carbon emissions scenario.
We show that very large volcanic eruptions similar to Tambora lead to
short-term substantial global cooling. However, over a long period, smaller
eruptions similar to Pinatubo in amplitude, but set to occur frequently, would
have a stronger impact on future climate change. In a scenario where the
volcanic external forcings are prescribed with a five-year frequency, the
induced cooling immediately lower the global temperature by more than one
degree before it returns to the warming trend. Therefore, the climate change
is approximately delayed by several decades, and by the end of the 21st
century, the warming is still below two degrees when compared to the present
day period. Our climate-carbon feedback analysis shows that future volcanic
eruptions induce positive feedbacks (i.e., more carbon sink) on both the
terrestrial and oceanic carbon cycle. The feedback signal on the ocean is
consistently smaller than the terrestrial counterpart and the feedback
strength is proportionally related to the frequency of the volcanic eruption
events. The cooler climate reduces the terrestrial heterotrophic respiration
in the northern high latitude and increases net primary production in the
tropics, which contributes to more than 45 % increase in accumulated carbon
uptake over land. The increased solubility of CO2 gas in seawater
associated with cooler SST is offset by a reduced CO2 partial pressure
gradient between the ocean and the atmosphere, which results in small changes
in net ocean carbon uptake. Similarly, there is nearly no change in the
seawater buffer capacity simulated between the different volcanic scenarios.
Our study shows that even in the relatively extreme scenario where large
volcanic eruptions occur every five-years period, the induced cooling leads
to a reduction of 46 ppmv atmospheric CO2 concentration as compared to
the reference projection of 878 ppmv, at the end of the 21st century. |
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