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| Titel |
Quasi-100 ky glacial-interglacial cycles triggered by subglacial burial carbon release |
| VerfasserIn |
N. Zeng |
| Medientyp |
Artikel
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| Sprache |
Englisch
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| ISSN |
1814-9324
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| Digitales Dokument |
URL |
| Erschienen |
In: Climate of the Past ; 3, no. 1 ; Nr. 3, no. 1 (2007-03-02), S.135-153 |
| Datensatznummer |
250000748
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| Publikation (Nr.) |
 copernicus.org/cp-3-135-2007.pdf |
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| Zusammenfassung |
| A mechanism is proposed in which climate, carbon cycle and icesheets
interact with each other to produce a feedback that can lead to
quasi-100 ky glacial-interglacial cycles.
A central process is the burial and preservation of organic carbon
by icesheets which contributes to the observed
glacial-interglacial CO2 change (the glacial burial hypothesis, Zeng, 2003).
Allowing carbon cycle
to interact with physical climate, here I further hypothesize
that deglaciation can be triggered by
the ejection of glacial burial carbon when a major icesheet
grows to sufficiently large size after a prolonged glaciation
so that subglacial transport becomes significant.
Glacial inception may be initiated by CO2 drawdown due to a relaxation
from a high but transient interglacial CO2 value as the land-originated
CO2 invades into deep ocean via thermohaline circulation and
CaCO3 compensation.
Also important for glacial inception may be the CO2 uptake by
vegetation and soil regrowth in the previously ice-covered regions.
When tested in a fully coupled Earth system model with
comprehensive carbon cycle components and semi-empirical physical climate
components, it produced under certain parameter regimes
self-sustaining glacial-interglacial cycles with
durations of 93 ky, CO2 changes of 90 ppmv, temperature changes
of 6°C.
Since the 100 ky cycles can
not be easily explained by the Milankovitch astronomical forcing alone,
this carbon-climate-icesheet mechanism
provides a strong feedback that could interact with external forcings to
produce the major observed Quaternary climatic variations.
It is speculated that some glacial terminations may be triggered by this
internal feedback while others by orbital forcing. Some observable
consequences are highlighted that may support or falsify the theory. |
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