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Quantifying Carbon Cycle Feedbacks.
- Source :
- Journal of Climate; Oct2009, Vol. 22 Issue 19, p5232-5250, 19p, 3 Charts, 6 Graphs
- Publication Year :
- 2009
-
Abstract
- Perturbations to the carbon cycle could constitute large feedbacks on future changes in atmospheric CO<subscript>2</subscript> concentration and climate. This paper demonstrates how carbon cycle feedback can be expressed in formally similar ways to climate feedback, and thus compares their magnitudes. The carbon cycle gives rise to two climate feedback terms: the concentration–carbon feedback, resulting from the uptake of carbon by land and ocean as a biogeochemical response to the atmospheric CO<subscript>2</subscript> concentration, and the climate–carbon feedback, resulting from the effect of climate change on carbon fluxes. In the earth system models of the Coupled Climate–Carbon Cycle Model Intercomparison Project (C4MIP), climate–carbon feedback on warming is positive and of a similar size to the cloud feedback. The concentration–carbon feedback is negative; it has generally received less attention in the literature, but in magnitude it is 4 times larger than the climate–carbon feedback and more uncertain. The concentration–carbon feedback is the dominant uncertainty in the allowable CO<subscript>2</subscript> emissions that are consistent with a given CO<subscript>2</subscript> concentration scenario. In modeling the climate response to a scenario of CO<subscript>2</subscript> emissions, the net carbon cycle feedback is of comparable size and uncertainty to the noncarbon–climate response. To quantify simulated carbon cycle feedbacks satisfactorily, a radiatively coupled experiment is needed, in addition to the fully coupled and biogeochemically coupled experiments, which are referred to as coupled and uncoupled in C4MIP. The concentration–carbon and climate–carbon feedbacks do not combine linearly, and the concentration–carbon feedback is dependent on scenario and time. [ABSTRACT FROM AUTHOR]
Details
- Language :
- English
- ISSN :
- 08948755
- Volume :
- 22
- Issue :
- 19
- Database :
- Complementary Index
- Journal :
- Journal of Climate
- Publication Type :
- Academic Journal
- Accession number :
- 44374575
- Full Text :
- https://doi.org/10.1175/2009JCLI2949.1