Glacials-interglacials in Vostok: climate and greenhouse gases

The main message coming from long term ice core records may be the close association between changes in the atmospheric composition, and glacial/interglacial changes. When compared with the preanthropogenic levels, the Vostok paleorecords show lower CO 2 and CH 4 concentrations and significant variations in aerosols of both terrestrial and oceanic origins. These changes, in particular those associated with greenhouse gases, may account for about half of the temperature change over the last climatic cycle. Although the interplay between the physical atmospheric and oceanic systems and the biosphere has still to be clarified, this finding may provide a clue to help in the prediction of future greenhouse gases induced warming. In view of available paleodata, a warming of 3–4°C, at equilibrium, may be a realistic figure for a doubling of CO 2 concentrations or its equivalent.