The recent collapse of several Antarctic Peninsula ice shelves has been linked to rapid regional atmospheric warming during the twentieth century. New high-resolution lake sediment records of Holocene ice-shelf behavior show that the George VI Ice Shelf was absent beginning ca. 9595 calibrated (cal.) yr B.P., but reformed by ca. 7945 cal. yr B.P. This retreat immediately followed a period of maximum Holocene warmth that is recorded in some ice cores and occurred at the same time as an influx of warmer ocean water onto the Antarctic Peninsula shelf. The absence of the ice shelf suggests that early Holocene ocean-atmosphere variability in the Antarctic Peninsula was greater than that measured in recent decades.