text: It is also clear that the climate of the Earth's polar regions are linked. Intensification of atmospheric circulation in the Northern Hemisphere (indicated by a stronger Siberian High and northern circumpolar circumpolar westerlies and a deeper Icelandic Low) and to a lesser degree in the Southern Hemisphere (stronger circumpolar westerlies and deeper Amundsen Sea Low) occurs 8200 8400 years ago. Date from Siple Dome (West Antarctica) and the Greenland Ice Sheet Project ice core climate proxies for northern and southern circumpolar westerlies show remarkably concurrent major intensification periods between 6000 and 5000 years ago and starting 1200 600 years ago. It appears that Antarctic events start earlier and less abruptly than those in Greenland.