Response of the carbon cycle in an intermediate complexity model to the different climate configurations of the last nine interglacials

9Citations
Citations of this article
29Readers
Mendeley users who have this article in their library.

Abstract

Atmospheric CO2 levels during interglacials prior to the Mid-Brunhes Event (MBE, ĝ1/4 ĝ€-430ĝ€-kaĝ€†BP) were around 40ĝ€-ppm lower than after the MBE. The reasons for this difference remain unclear. A recent hypothesis proposed that changes in oceanic circulation, in response to different external forcings before and after the MBE, might have increased the ocean carbon storage in pre-MBE interglacials, thus lowering atmospheric CO2. Nevertheless, no quantitative estimate of this hypothesis has been produced up to now. Here we use an intermediate complexity model including the carbon cycle to evaluate the response of the carbon reservoirs in the atmosphere, ocean and land in response to the changes of orbital forcings, ice sheet configurations and atmospheric CO2 concentrations over the last nine interglacials. We show that the ocean takes up more carbon during pre-MBE interglacials in agreement with data, but the impact on atmospheric CO2 is limited to a few parts per million. Terrestrial biosphere is simulated to be less developed in pre-MBE interglacials, which reduces the storage of carbon on land and increases atmospheric CO2. Accounting for different simulated ice sheet extents modifies the vegetation cover and temperature, and thus the carbon reservoir distribution. Overall, atmospheric CO2 levels are lower during these pre-MBE simulated interglacials including all these effects, but the magnitude is still far too small. These results suggest a possible misrepresentation of some key processes in the model, such as the magnitude of ocean circulation changes, or the lack of crucial mechanisms or internal feedbacks, such as those related to permafrost, to fully account for the lower atmospheric CO2 concentrations during pre-MBE interglacials.

Cite

CITATION STYLE

APA

Bouttes, N., Swingedouw, D., Roche, D. M., Sanchez-Goni, M. F., & Crosta, X. (2018). Response of the carbon cycle in an intermediate complexity model to the different climate configurations of the last nine interglacials. Climate of the Past, 14(2), 239–253. https://doi.org/10.5194/cp-14-239-2018

Register to see more suggestions

Mendeley helps you to discover research relevant for your work.

Already have an account?

Save time finding and organizing research with Mendeley

Sign up for free