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Precise knowledge of the phase relationship between climate changes in the two hemispheres is a key for understanding the Earth’s climate dynamics. For the last glacial period, ice core studies have revealed strong coupling of the largest millennial-scale warm events in Antarctica with the longest Dansgaard–Oeschger events in Greenland through the Atlantic meridional overturning circulation. It has been unclear, however, whether the shorter Dansgaard–Oeschger events have counterparts in the shorter and less prominent Antarctic temperature variations, and whether these events are linked by the same mechanism. Here we present a glacial climate record derived from an ice core from Dronning Maud Land, Antarctica, which represents South Atlantic climate at a resolution comparable with the Greenland ice core records. After methane synchronization with an ice core from North Greenland, the oxygen isotope record from the Dronning Maud Land ice core shows a one-to-one coupling between all Antarctic warm events and Greenland Dansgaard–Oeschger events by the bipolar seesaw6. The amplitude of the Antarctic warm events is found to be linearly dependent on the duration of the concurrent stadial in the North, suggesting that they all result from a similar reduction in the meridional overturning circulation. [ABSTRACT FROM AUTHOR]

Asserts that rich archives of the Earth's climate have been kept in cold storage for more than 200,000 years in the ice sheets of Greenland and Antarctica. Results of two recently drilled deep ice cores; Detection of climate shifts over periods as short as a few years; Additional information.

Comments on a study by Richard Alley and co-workers published in the April 8, 1993 issue of `Nature' reporting ice-core evidence of a different, but equally profound nature to the record of atmospheric CO2 concentration spanning the past 200,000 years. Earlier claims that the Earth's climate system has several stable modes, between which it flips; Greenland Ice Sheet Project II (GISP2); GISP2 ice-core ages; More.