 |
| Titel |
Better constraining climate sensitivity to CO2 since the Miocene through ACTI-CO process modeling of marine CO2 proxies |
| VerfasserIn |
Heather Stoll, Lorena Abrevaya, Clara Bolton, Maria Teresa Hernandez Sanchez, Luz Maria Mejia, Ana Mendez Vicence |
| Konferenz |
EGU General Assembly 2015
|
| Medientyp |
Artikel
|
| Sprache |
Englisch
|
| Digitales Dokument |
PDF |
| Erschienen |
In: GRA - Volume 17 (2015) |
| Datensatznummer |
250107085
|
| Publikation (Nr.) |
 EGU/EGU2015-6775.pdf |
|
|
|
|
|
| Zusammenfassung |
| Atmospheric CO2 is inferred to be an important forcing agent in climate on an array of timescales. Periods of CO2 higher than preindustrial are not sampled by available direct ice core records, so empirical estimates of climate sensitivity to higher CO2 levels, and climate model responses such as ice cap growth, are conditioned by the large uncertainty in long term CO2 proxy records. Here we report results with ACTI-CO, a process model for carbon allocation within the cell, which can be used to improve the accuracy of CO2 proxy records derived from carbon isotopic fractionation in marine algae. We apply ACTI-CO to new and existing records of carbon isotopic fractionation from diatoms and coccolithophores, focusing on the mid-Miocene to present. We evaluate the degree to which active carbon uptake attenuates the magnitude of change in isotopic fractionation associated with a given CO2 decrease. We also consider cell size and growth rate changes. The results suggest the potential for significant CO2 declines since the middle Miocene, consistent with, but potentially larger in magnitude, than those inferred from previous inverse modeling of climate data using glacial-interglacial climate sensitivity to CO2. |
|
|
|
|
|
|