CLIMATE INSTABILITIES - GREENLAND AND ANTARCTIC RECORDS

The study of the two Summit Greenland ice cores, GRIP and GISP2, has provided a wealth of information about climate variability in the North Atlantic region over the last glacial-interglacial cycle (approximately the last 150,000 years). The results are largely based on the isotopic composition of the ice which provides an estimate of local temperature changes. The aim of this Note is to put the Summit records in a global perspective through a comparison with the suggestion: antarctic isotopic record from Vostok. Like in Greenland, the last deglaciation warming is in Antarctica a two-step process interrupted by a return to colder conditions. However, the Antarctic cooling appears to precede the Younger-Bryas Northern Hemisphere event and is much weaker. The most prominent of the interstadials observed in Greenland during the glacial may be identified in the Vostok record whereas the less accentuate ones are eliminated. The situation differs during the last interglacial: no Antarctic counterpart to the rapid changes observed in Greenland has yet been detected.