Asynchrony between Antarctic temperature and CO2 associated with obliquity over the past 720,000 years

• Published in: Nature communications Vol. 9; no. 1; pp. 1 - 11
• Main Authors: Uemura, Ryu, Motoyama, Hideaki, Masson-Delmotte, Valérie, Jouzel, Jean, Kawamura, Kenji, Goto-Azuma, Kumiko, Fujita, Shuji, Kuramoto, Takayuki, Hirabayashi, Motohiro, Miyake, Takayuki, Ohno, Hiroshi, Fujita, Koji, Abe-Ouchi, Ayako, Iizuka, Yoshinori, Horikawa, Shinichiro, Igarashi, Makoto, Suzuki, Keisuke, Suzuki, Toshitaka, Fujii, Yoshiyuki
• Format: Journal Article
• Language: English
• Published: London Nature Publishing Group UK 06.03.2018; Nature Publishing Group; Nature Portfolio
• Subjects: 140/58; 704/106/125; 704/106/2738; 704/106/413; Carbon cycle; Carbon dioxide; Cores; Humanities and Social Sciences; Insolation; multidisciplinary; Ocean circulation; Ocean currents; Ocean temperature; Periodic variations; Periodicity; Phase lag; Polar environments; Science; Science (multidisciplinary); Temperature effects; Variation; Water circulation; Southern Ocean
• ISSN: 2041-1723; 2041-1723
• DOI: 10.1038/s41467-018-03328-3

The δD temperature proxy in Antarctic ice cores varies in parallel with CO 2 through glacial cycles. However, these variables display a puzzling asynchrony. Well-dated records of Southern Ocean temperature will provide crucial information because the Southern Ocean is likely key in regulating CO 2 variations. Here, we perform multiple isotopic analyses on an Antarctic ice core and estimate temperature variations at this site and in the oceanic moisture source over the past 720,000 years, which extend the longest records by 300,000 years. Antarctic temperature is affected by large variations in local insolation that are induced by obliquity. At the obliquity periodicity, the Antarctic and ocean temperatures lag annual mean insolation. Further, the magnitude of the phase lag is minimal during low eccentricity periods, suggesting that secular changes in the global carbon cycle and the ocean circulation modulate the phase relationship among temperatures, CO 2 and insolation in the obliquity frequency band. The Antarctic temperature record displays a puzzling asynchrony with changes in CO 2 through glacial cycles. Here, the authors show that a 720,000-year Antarctic temperature record is affected by variations in obliquity-induced local insolation that are associated with phase modulation of eccentricity cycle.