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Multiple timescales for neutralization of fossil fuel CO 2
Author(s) -
Archer David,
Kheshgi Haroon,
MaierReimer Ernst
Publication year - 1997
Publication title -
geophysical research letters
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.007
H-Index - 273
eISSN - 1944-8007
pISSN - 0094-8276
DOI - 10.1029/97gl00168
Subject(s) - dissolution , geochemical cycle , atmosphere (unit) , weathering , carbon cycle , carbonate , igneous rock , environmental chemistry , geology , environmental science , chemistry , earth science , mineralogy , geochemistry , meteorology , ecology , organic chemistry , biology , physics , ecosystem
The long term abiological sinks for anthropogenic CO 2 will be dissolution in the oceans and chemical neutralization by reaction with carbonates and basic igneous rocks. We use a detailed ocean/sediment carbon cycle model to simulate the response of the carbonate cycle in the ocean to a range of anthropogenic CO 2 release scenarios. CaCO 3 will play only a secondary role in buffering the CO 2 concentration of the atmosphere because CaCO 3 reaction uptake capacity and kinetics are limited by the dynamics of the ocean carbon cycle. Dissolution into ocean water sequesters 70–80% of the CO 2 release on a time scale of several hundred years. Chemical neutralization of CO 2 by reaction with CaCO 3 on the sea floor accounts for another 9–15% decrease in the atmospheric concentration on a time scale of 5.5–6.8 kyr. Reaction with CaCO 3 on land accounts for another 3–8%, with a time scale of 8.2 kyr. The final equilibrium with CaCO 3 leaves 7.5–8% of the CO 2 release remaining in the atmosphere. The carbonate chemistry of the oceans in contact with CaCO 3 will act to buffer atmospheric CO 2 at this higher concentration until the entire fossil fuel CO 2 release is consumed by weathering of basic igneous rocks on a time scale of 200 kyr.