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| Titel |
Atmospheric carbon dioxide from 115,000 to 38,000 years BP and its implications for changes in the carbon cycle |
| VerfasserIn |
Bernhard Bereiter, Dieter Lüthi, Michael Siegrist, Thomas F. Stocker, Hubertus Fischer |
| 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 |
250047916
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| Zusammenfassung |
| The relationships between temperature changes in the southern hemisphere (AIM-events),
abrupt climate changes in the northern hemisphere (DO-events) and atmospheric
CO2 concentrations during the last glacial period provide insight in the natural
carbon cycle on millennial timescales. From the long-term evolution of the CO2
concentration over the period of the last glacial inception, hints about how the carbon
cycle adjusted to glacial conditions can be deduced. We present two overlapping
atmospheric CO2 records with sub-millennial resolution from two different Antarctic ice
cores (Talos Dome and EPICA Dronning Maud Land) covering the time period
from 38,000 to 115,000 years BP to investigate the carbon cycle under these two
aspects. The availability of highly resolved records of the methane concentration
from both cores together with the characteristic that methane marks the onset of
DO-events with a very pronounced and sharp increase allows us to synchronize the
two data sets over the period of the overlap and compare the relationship between
DO-events and CO2 evolution with a minimum of temporal uncertainty. First, the
data confirm the strong link of AIM-events and CO2 during the whole period of
the record. Second, the high-resolution data indicate that the onset of DO-events
is not always coincident with the CO2 maxima between 38,000 to 60,000 years
BP (MIS 3) as described previously. On the other hand, such a synchronism is
confirmed for earlier DO-events between 70,000 and 115,000 years BP (MIS 5).
This different behavior of the CO2 concentration during the millennial scale events
together with sediment proxies for ocean circulation and carbon stock changes
over the period of the record, leads us to the hypothesis that this difference may be
associated with a mode change of the meridional overturning circulation of the Atlantic
ocean at the transition from MIS 5 to 4, which results in different contributions of
the ocean carbon stock to the atmospheric CO2 concentration during DO-events. |
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