TIMING OF THE ANTARCTIC COLD REVERSAL AND THE ATMOSPHERIC CO2 INCREASE WITH RESPECT TO THE YOUNGER DRYAS EVENT

The transition from the Last Glacial to the Holocene is a key period f or understanding the mechanisms of global climate change. Ice cores fr om the large polar ice sheets provide a wealth of information with goo d time resolution for this period. However, interactions between the t wo hemispheres can only be investigated if ice core records from Green land and Antarctica can be synchronised accurately and reliably. The a tmospheric methane concentration shows large and very fast changes dur ing this period. These variations are well suited for a synchronisatio n of the age scales of ice cores from Greenland and Antarctica. Here w e confirm the proposed lead of the Antarctic Cold Reversal on the Youn ger Dryas cold event. The Antarctic cooling precedes the Younger Dryas by at least 1.8 kyr. This suggests that northern and southern hemisph eres were in anti-phase during the Younger Dryas cold event. A further result of the synchronisation is that the long-term glacial-interglac ial increase of atmospheric CO2 was not interrupted during the Younger Dryas event and that atmospheric CO2 changes are not necessarily domi nated by changes in the North Atlantic circulation.