Long-term climatic and environmental records from antarctic ice

Various records obtained from the Vostok (East Antarctica) ice core allow reconstruction of temperature, accumulation (precipitation) , aerosol loading and atmospheric CO concentration histories over the last climatic cycle (160 000 years). The results agree with those previously obtained from two other deep Antarctic ice cores going back to the Last Glacial Maximum. The Vostok isotope-based temperature and CO records show a large 100 ky signal with changes of the order of 10°C and 70 ppmv respectively. They are closely associated and show periodicities characteristic of the earth orbital parameters. These features suggest a fundamental link between the climate system and the carbon cycle and point out the possible role of CO , in addition to inso- 2 lation inputs, in accounting for the observed temperature history. The accumulation (precipitation) record appears to be governed by temperature with values during the coldest stages reduced to about 50 % of the current rate. Ice deposited during these coldest stages is also characterized by high concentrations of marine and terrestrial aerosols ; these peaks likely reflect strengthened sources and meridional transport during full glacial conditions, linked to higher wind speeds, more extensive arid areas on surrounding continents and the greater exposure of continental shelves. On the other hand there is no indication of a long term relationship between volcanism and climate.