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Atmospheric CO2 and Climate on Millennial Time Scales During the Last Glacial Period.


Atmospheric CO2 composition and climate during the last glacial period.

Atmospheric CO2 and Climate on Millennial Time Scales During the Last Glacial Period.

Science
Vol. 322, No. 5898, pp. 83-85, 3 October 2008, doi:10.1126/science.1160832.

Jinho Ahn and Ed Brook
Department of Geosciences, Oregon State University, Corvallis, OR 97331-5506, USA.
Figure 1. Atmospheric CO2 composition and climate during the last glacial period (Click for larger version).
(A) Greenlandic temperature proxy, δ18Oice. Red numbers denote DO events.
(B) Byrd Station, Antarctica temperature proxy, δ18Oice. A1 to A7, Antarctic warming events.
(C) Atmospheric CO2 concentrations. Red dots and green circles (results from University of Bern) are from Byrd ice cores. Red dots are averages of replicates, and red open circles at ~73 and 76 ka are single data. The chronology used for Byrd CO2 is described in the SOM. Blue line is from Taylor Dome ice core on the GISP2 time scale. Purple line is from EPICA Dome C.
(D) CH4 concentrations from Greenland (green) and Byrd ice cores (brown). Black dots, new measurements for this study. Vertical blue bars, timing of Heinrich events (H3 to H6). Brown dotted lines, abrupt warming in Greenland.
ABSTRACT:
Reconstructions of ancient atmospheric carbon dioxide (CO2) variations help us better understand how the global carbon cycle and climate are linked. We compared CO2 variations on millennial time scales between 20,000 and 90,000 years ago with an Antarctic temperature proxy and records of abrupt climate change in the Northern Hemisphere. CO2 concentration and Antarctic temperature were positively correlated over millennial-scale climate cycles, implying a strong connection to Southern Ocean processes. Evidence from marine sediment proxies indicates that CO2 concentration rose most rapidly when North Atlantic Deep Water shoaled and stratification in the Southern Ocean was reduced. These increases in CO2 concentration occurred during stadial (cold) periods in the Northern Hemisphere, several thousand years before abrupt warming events in Greenland.
Download data from the WDC Paleo archive:
Byrd Ice Core 90-20ka CO2 Data, Text or Excel, and Byrd Ice Core 87-67ka CH4 Data, Text or Excel

To read or view the full study, please visit the Science website.
It was published in Science, Vol. 322, No. 5898, pp. 83-85, 3 October 2008, doi:10.1126/science.1160832.
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