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Ocean carbon sink duration under stabilization of atmospheric CO 2 : A 1,000‐year timescale
Author(s) -
Kheshgi Haroon S.
Publication year - 2004
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 - 10.1029/2004gl020612
Subject(s) - sink (geography) , atmosphere (unit) , carbon cycle , environmental science , carbon sink , atmospheric sciences , carbon fibers , carbon dioxide , box model , oceanography , geology , chemistry , climate change , meteorology , materials science , physics , organic chemistry , ecosystem , composite number , cartography , composite material , biology , geography , ecology
Ocean CO 2 uptake, moderated by the slow mixing of dissolved inorganic carbon to the ocean depths, is estimated to have a duration of ∼1,000 years when the atmosphere is held at a constant “stabilized” CO 2 concentration. This timescale is found to be several times longer than the relaxation time for the atmosphere‐ocean system to come to equilibrium when forced by a CO 2 emission impulse. Furthermore, the 1,000 year timescale is found to be insensitive to atmospheric CO 2 concentration level. Beyond 2,000 years, sediment CaCO 3 neutralization becomes the dominant mechanism for CO 2 uptake further extending the timescale of the ocean carbon sink. The equilibration time of the atmosphere‐ocean system, on the other hand, is shown to lengthen with increasing magnitude of CO 2 emissions. Estimates are based on the response of a 3D‐ocean carbon cycle model, and this behavior explained using the analytic solution of a simple box model.