What determines the magnitude of carbon cycle-climate feedbacks?
نویسندگان
چکیده
Positive feedbacks between climate change and the carbon cycle have the potential to amplify the growth of atmospheric carbon dioxide and accelerate future climate warming. However, both the magnitude of and the processes which drive future carbon cycleclimate feedbacks remain highly uncertain. In this study, we use a coupled climate-carbon model to investigate how the response of vegetation photosynthesis to climate change contributes to the overall strength of carbon cycle-climate feedbacks. We find that the feedback strength is particularly sensitive to the model representation of the photosynthesis-temperature response, with lesser sensitivity to the parameterization of soil moisture and nitrogen availability. In all simulations, large feedbacks are associated with a climatic suppression of terrestrial primary productivity and consequent reduction of terrestrial carbon uptake. This process is particularly evident in the tropics and can explain a large part of the range of carbon cycle-climate feedbacks simulated by different coupled climate-carbon models. DOI: https://doi.org/10.1029/2006GB002733 Posted at the Zurich Open Repository and Archive, University of Zurich ZORA URL: https://doi.org/10.5167/uzh-77140 Published Version Originally published at: Matthews, H Damon; Eby, Michael; Ewen, Tracy; Friedlingstein, Pierre; Hawkins, Barbara J (2007). What determines the magnitude of carbon cycle-climate feedbacks? Global Biogeochemical Cycles, 21(2):online. DOI: https://doi.org/10.1029/2006GB002733 What determines the magnitude of carbon cycle-climate feedbacks? H. Damon Matthews, Michael Eby, Tracy Ewen, Pierre Friedlingstein, and Barbara J. Hawkins Received 3 April 2006; revised 22 January 2007; accepted 8 March 2007; published 19 May 2007. [1] Positive feedbacks between climate change and the carbon cycle have the potential to amplify the growth of atmospheric carbon dioxide and accelerate future climate warming. However, both the magnitude of and the processes which drive future carbon cycleclimate feedbacks remain highly uncertain. In this study, we use a coupled climate-carbon model to investigate how the response of vegetation photosynthesis to climate change contributes to the overall strength of carbon cycle-climate feedbacks. We find that the feedback strength is particularly sensitive to the model representation of the photosynthesis-temperature response, with lesser sensitivity to the parameterization of soil moisture and nitrogen availability. In all simulations, large feedbacks are associated with a climatic suppression of terrestrial primary productivity and consequent reduction of terrestrial carbon uptake. This process is particularly evident in the tropics and can explain a large part of the range of carbon cycle-climate feedbacks simulated by different coupled climate-carbon models. Citation: Matthews, H. D., M. Eby, T. Ewen, P. Friedlingstein, and B. J. Hawkins (2007), What determines the magnitude of carbon cycle-climate feedbacks?, Global Biogeochem. Cycles, 21, GB2012, doi:10.1029/2006GB002733.
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