 |
| Titel |
Climate and carbon cycle dynamics in a CESM simulation from 850 to 2100 CE |
| VerfasserIn |
F. Lehner, F. Joos, C. C. Raible, J. Mignot, A. Born, K. M. Keller, T. F. Stocker |
| Medientyp |
Artikel
|
| Sprache |
Englisch
|
| ISSN |
2190-4979
|
| Digitales Dokument |
URL |
| Erschienen |
In: Earth System Dynamics ; 6, no. 2 ; Nr. 6, no. 2 (2015-07-10), S.411-434 |
| Datensatznummer |
250115468
|
| Publikation (Nr.) |
 copernicus.org/esd-6-411-2015.pdf |
|
|
|
|
|
| Zusammenfassung |
| Under the protocols of phase 3 of the Paleoclimate Modelling
Intercomparison Project, a
number of simulations were produced that provide a range of potential climate
evolutions from the last millennium to the end of the current century. Here,
we present the first simulation with the Community Earth System Model (CESM),
which includes an interactive carbon cycle, that covers the last millennium.
The simulation is continued to the end of the twenty-first century. Besides
state-of-the-art forcing reconstructions, we apply a modified reconstruction
of total solar irradiance to shed light on the issue of forcing uncertainty
in the context of the last millennium. Nevertheless, we find that structural
uncertainties between different models can still dominate over forcing
uncertainty for quantities such as hemispheric temperatures or the land and
ocean carbon cycle response. Compared to other model simulations, we find
forced decadal-scale variability to occur mainly after volcanic eruptions,
while during other periods internal variability masks potentially forced
signals and calls for larger ensembles in paleoclimate modeling studies. At
the same time, we were not able to attribute millennial temperature trends to
orbital forcing, as has been suggested recently. The climate–carbon-cycle
sensitivity in CESM during the last millennium is estimated to be between 1.0
and 2.1 ppm °C−1. However, the dependence of this sensitivity
on the exact time period and scale illustrates the prevailing challenge of
deriving robust constraints on this quantity from paleoclimate proxies. In
particular, the response of the land carbon cycle to volcanic forcing shows
fundamental differences between different models. In CESM the tropical land
dictates the response to volcanoes, with a distinct behavior for large and
moderate eruptions. Under anthropogenic emissions, global land and ocean
carbon uptake rates emerge from the envelope of interannual natural
variability by about year 1947 and 1877, respectively, as simulated for the
last millennium. |
| |
|
| Teil von |
|
|
|
|
|
|
|
|