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| Titel |
Correcting for the background state dependency of palaeo climate sensitivity |
| VerfasserIn |
Anna S. von der Heydt, Peter Köhler, Roderik S. W. van de Wal, Henk A. Dijkstra |
| Konferenz |
EGU General Assembly 2013
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| Medientyp |
Artikel
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| Sprache |
Englisch
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| Digitales Dokument |
PDF |
| Erschienen |
In: GRA - Volume 15 (2013) |
| Datensatznummer |
250071687
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| Zusammenfassung |
| The equilibrium (Charney) climate sensitivity, here indicated by Sa, is the equilibrium
change in Earth’s global mean surface temperature due to a radiative forcing associated with
a doubling of pCO2, the atmospheric CO2 concentration. Palaeo data have been frequently
used to determine Sa, and — if slow feedback processes are adequately taken into account —
indicate a similar range as those based on climate model results used in IPCC AR4. In most
of these palaeostudies it is implicitly assumed that the (fast) feedback processes are
independent of the background climate state, e.g., are equally strong during glacial and
interglacial periods. Here we assess the dependency of the fast feedback processes on the
background climate state using data of the last 800 kyr and a conceptual climate model.
Sa is found to be higher in cold periods than during warm times. By correcting
for this state dependency, we determine a new value of the Charney sensitivity
Sa = 0.71 ± 0.40Â KÂ (WÂ m-2)-1 (corresponding to a warming of 2.6 ± 1.5Â K for
2 Ã pCO2), which is lower than present estimates in which state dependency is neglected. |
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