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| Titel |
Impact of volcanic super-eruptions on the global carbon cycle |
| VerfasserIn |
Alexander Beitsch, Joachim Segschneider, Katharina Six, Victor Brovkin, Tatiana Ilyina, Johann Jungclaus, Stephan Lorenz, Davide Zanchettin, Thomas Raddatz, Claudia Timmreck |
| Konferenz |
EGU General Assembly 2011
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| Medientyp |
Artikel
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| Sprache |
Englisch
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| Digitales Dokument |
PDF |
| Erschienen |
In: GRA - Volume 13 (2011) |
| Datensatznummer |
250054595
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| Zusammenfassung |
| The sensitivity of the climate-biogeochemistry system to extremely large volcanic eruptions
(super-eruptions) is investigated using the comprehensive MPI-M Earth System Model
(ESM). The model includes an interactive carbon cycle with modules for terrestrial biosphere
as well as ocean biogeochemistry.
Here we present and discuss ESM simulations of a very large Northern Hemisphere
mid-latitude eruption (Yellowstone) and a very large tropical one (Toba) for different seasons
of the eruption. To reduce the influence of internal variability on the experimental
outcome, an ensemble of 5 members is analyzed for each of the cases. In the simulated
super-eruptions with an assumed atmospheric SO2 injection of 100 times the 1991
Pinatubo emission, the global annual mean temperature drops by about 3 to 4 K
and recovers slowly during the following 15 years. Following a short increase in
the first 3 years after the eruption atmospheric CO2 concentration declines quite
rapidly during the next 3 years before reaching a minimum and starting to increase
slowly towards the pre-eruption level. This CO2 dynamics is explained mainly by
changes in land carbon storage. Immediately after the eruption, land is a source of
carbon to atmosphere primarily due to decrease in plant productivity. Later, reduced
heterotrophic respiration in response to surface cooling, which leads to increased
carbon storage in soils, mostly in tropical and subtropical regions, prevails over the
productivity decrease and the land turns into a carbon sink. Although the climate has
completely recovered after 75 years, the carbon cycle has not yet reached equilibrium
again. This takes another 75 to 100 years. The ocean acts as a carbon sink in the
beginning, primarily due to temperature induced solubility increase, accompanied by
changed dynamics in particular in the equatorial Pacific and the marine biology. In the
longer term, the ocean compensates for the carbon losses from the atmosphere to the
land by increased ocean to atmosphere fluxes, resulting in a net loss for the ocean. |
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