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| Titel |
Impact of CO2 and climate on the Last Glacial Maximum vegetation: results from the ORCHIDEE/IPSL models |
| VerfasserIn |
M.-N. Woillez, M. Kageyama, G. Krinner, N. Noblet-Ducoudré, N. Viovy, M. Mancip |
| 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 ; 7, no. 2 ; Nr. 7, no. 2 (2011-06-01), S.557-577 |
| Datensatznummer |
250004517
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| Publikation (Nr.) |
 copernicus.org/cp-7-557-2011.pdf |
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| Zusammenfassung |
| Vegetation reconstructions from pollen data for the Last Glacial
Maximum (LGM), 21 ky ago, reveal lanscapes radically different from
the modern ones, with, in particular, a massive regression of forested
areas in both hemispheres. Two main factors have to be taken into
account to explain these changes in comparison to today's potential
vegetation: a generally cooler and drier climate and a
lower level of atmospheric CO2. In order to assess the relative
impact of climate and atmospheric CO2 changes on the global
vegetation, we simulate the potential modern vegetation and the
glacial vegetation with the dynamical global vegetation model
ORCHIDEE, driven by outputs from the IPSL_CM4_v1 atmosphere-ocean
general circulation model, under modern or glacial CO2 levels for
photosynthesis.
ORCHIDEE correctly reproduces the broad features of the glacial
vegetation. Our modelling results support the view that the physiological
effect of glacial CO2 is a key factor to explain vegetation changes
during glacial times. In our simulations, the low atmospheric CO2
is the only driver of the tropical forests regression, and
explains half of the response of temperate and boreal forests to
glacial conditions. Our study shows that the sensitivity to CO2
changes depends on the background climate over a region, and also
depends on the vegetation type, needleleaf trees being much more
sensitive than broadleaf trees in our model. This difference of
sensitivity leads to a dominance of broadleaf types in the remaining simulated forests, which is not supported by pollen data, but
nonetheless suggests a potential impact of CO2 on the glacial
vegetation assemblages. It also modifies the competitivity between the
trees and makes the amplitude of the response to CO2 dependent on
the initial vegetation state. |
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