Abrupt end of the last interglacial s.s. in north-east France

Close study of past interglacials might indicate how and when the present interglacial will end and whether we are heading towards a warming or a cooling^1,2. No certain prediction has been possible because of man's interference with the environment. But, we report here that when exploring the records of past temperate intervals, we observed frequent signs of abrupt changes of local environment. In particular, abrupt shifts in forest composition end each Pleistocene interglacial whose record was studied in detail. In Grande Pile (north-east France), the Eemian (s.S.) (oxygen isotope substage 5e) temperate forest was replaced by a pine-spruce-birch taiga within ~150+/-75 yr. These results are based on rich pollen content of continuously deposited laminated gyttja and on the assumption of a constant sedimentation rate during the last 11,000-yr long interglacial. If the area today was affected in a similar way, the relatively fast transition of the environment, and by implication of the climate, would place serious constraints on man.