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Controls on Millennial‐Scale Atmospheric CO 2 Variability During the Last Glacial Period
Author(s) -
Bauska T. K.,
Brook E. J.,
Marcott S. A.,
Baggenstos D.,
Shackleton S.,
Severinghaus J. P.,
Petrenko V. V.
Publication year - 2018
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 - 10.1029/2018gl077881
Subject(s) - deglaciation , glacial period , climatology , northern hemisphere , centennial , geology , southern hemisphere , climate change , paleoclimatology , carbon cycle , isotopes of carbon , period (music) , atmospheric sciences , oceanography , total organic carbon , ecosystem , geography , paleontology , chemistry , ecology , physics , archaeology , environmental chemistry , acoustics , biology
Changes in atmospheric CO 2 on millennial‐to‐centennial timescales are key components of past climate variability during the last glacial and deglacial periods (70–10 ka), yet the sources and mechanisms responsible for the CO 2 fluctuations remain largely obscure. Here we report the 13 C/ 12 C ratio of atmospheric CO 2 during a key interval of the last glacial period at submillennial resolution, with coeval histories of atmospheric CO 2 , CH 4 , and N 2 O concentrations. The carbon isotope data suggest that the millennial‐scale CO 2 variability in Marine Isotope Stage 3 is driven largely by changes in the organic carbon cycle, most likely by sequestration of respired carbon in the deep ocean. Centennial‐scale CO 2 variations, distinguished by carbon isotope signatures, are associated with both abrupt hydrological change in the tropics (e.g., Heinrich events) and rapid increases in Northern Hemisphere temperature (Dansgaard‐Oeschger events). These events can be linked to modes of variability during the last deglaciation, thus suggesting that drivers of millennial and centennial CO 2 variability during both periods are intimately linked to abrupt climate variability.