Northern Hemisphere forcing of climatic cycles in Antarctica over the past 360,000 years

Kawamura, Kenji*; Parrenin, F.*; Lisiecki, L.*; Uemura, Ryu*; Vimeux, F.*; Severinghaus, J. P.*; Hutterli, M. A.*; Nakazawa, Takakiyo*; Aoki, Shuji*; Jouzel, J.*; Raymo, M. E.*; Matsumoto, Koji*; Nakata, Hisakazu ; Motoyama, Hideaki*; Fujita, Shuji*; Azuma, Kumiko*; Fujii, Yoshiyuki*; Watanabe, Okitsugu*

We present a new chronology of Antarctic climate change over the past 360,000 years that is based on the ratio of oxygen to nitrogen molecules in air trapped in the Dome Fuji and Vostok ice cores. This ratio is a proxy for local summer insolation, and thus allows the chronology to be constructed by orbital tuning without the need to assume a lag between a climate record and an orbital parameter. The accuracy of the chronology allows us to examine the phase relationships between climate records from the ice cores and changes in insolation. Our results indicate that orbital-scale Antarctic climate change lags Northern Hemisphere insolation by a few millennia, and that the increases in Antarctic temperature and atmospheric carbon dioxide concentration during the last four terminations occurred within the rising phase of Northern Hemisphere summer insolation. These results support the Milankovitch theory that Northern Hemisphere summer insolation triggered the last four deglaciations.