Atmospheric CO 2 and Climate on Millennial Time Scales During the Last Glacial Period

• Published in: Science
• Main Authors: Ahn, Jinho, Brook, Edward J.
• Format: Article in Journal/Newspaper
• Language: English
• Published: American Association for the Advancement of Science (AAAS) 2008
• Subjects: Antarctic; Greenland; Southern Ocean; Antarc*; North Atlantic Deep Water; North Atlantic
• Online Access: http://dx.doi.org/10.1126/science.1160832; https://www.science.org/doi/pdf/10.1126/science.1160832

Reconstructions of ancient atmospheric carbon dioxide (CO 2 ) variations help us better understand how the global carbon cycle and climate are linked. We compared CO 2 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. CO 2 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 CO 2 concentration rose most rapidly when North Atlantic Deep Water shoaled and stratification in the Southern Ocean was reduced. These increases in CO 2 concentration occurred during stadial (cold) periods in the Northern Hemisphere, several thousand years before abrupt warming events in Greenland.