Assessing the potential long-term increase of oceanic fossil fuel CO 2 uptake due to CO 2 -calcification feedback

• Main Authors: Ridgwell, A., Zondervan, I., Hargreaves, J. C., Bijma, J., Lenton, T. M.
• Other Authors: School of Geographical Sciences Bristol, University of Bristol Bristol, Biogéosciences UMR 6282 (BGS), Université de Bourgogne (UB)-Centre National de la Recherche Scientifique (CNRS), Frontier Research Center for Global Change (FRCGC), Japan Agency for Marine-Earth Science and Technology (JAMSTEC), School of Environmental Sciences Norwich, University of East Anglia Norwich (UEA)
• Format: Article in Journal/Newspaper
• Language: English
• Published: HAL CCSD 2007
• Subjects: [PHYS.ASTR.CO]Physics [physics]/Astrophysics [astro-ph]/Cosmology and Extra-Galactic Astrophysics [astro-ph.CO]; [SDU.ASTR]Sciences of the Universe [physics]/Astrophysics [astro-ph]; [SDU.ENVI]Sciences of the Universe [physics]/Continental interfaces; environment; [SDU.OCEAN]Sciences of the Universe [physics]/Ocean; Atmosphere; [SDU.STU]Sciences of the Universe [physics]/Earth Sciences; Ocean acidification
• Online Access: https://hal.science/hal-00297628; https://hal.science/hal-00297628/document; https://hal.science/hal-00297628/file/bg-4-481-2007.pdf

International audience Plankton manipulation experiments exhibit a wide range of sensitivities of biogenic calcification to simulated anthropogenic acidification of the ocean, with the "lab rat" of planktic calcifiers, Emiliania huxleyi apparently not representative of calcification generally. We assess the implications of this observational uncertainty by creating an ensemble of realizations of an Earth system model that encapsulates a comparable range of uncertainty in calcification response to ocean acidification. We predict that a substantial reduction in marine carbonate production is possible in the future, with enhanced ocean CO 2 sequestration across the model ensemble driving a 4?13% reduction in the year 3000 atmospheric fossil fuel CO 2 burden. Concurrent changes in ocean circulation and surface temperatures in the model contribute about one third to the increase in CO 2 uptake. We find that uncertainty in the predicted strength of CO 2 -calcification feedback seems to be dominated by the assumption as to which species of calcifier contribute most to carbonate production in the open ocean.