Instability of the environment at the end of the Eemian Interglacial as illustrated by the isopollen maps for Poland

Abstract

In numerous terrestrial pollen profiles from Poland(similarly as in a few pollen records from other parts of Central Europe) the end of the last interglacial (Eemian, MIS 5e) seems to be characterized by climatic and environmental instability. It is marked by a strong, rapid cooling in the middle part of pine phase ending this interglacial (E7 regional pollen assemblage zone), and then a re-warming at the very end of this phase, immediately before the transition to the glacial conditions of the last glaciation (Vistulian, Weichselian, MIS 5d). We have recognized the regional distribution of the pollen records of these climatic fluctuations in the area of Polandon the basis of isopollen maps prepared for the Eemian interglacial based on palynological data from 31 Polish pollen profiles. These maps show unequivocally that the intra-interglacial cooling at the end of the Eemian interglacial was a transregional phenomenon, which was reflected very clearly by a temporary openness of vegetation on the whole territory of Poland. It was connected with a distinct decrease in pine forest areas and an increase in birch forests and open communities of cold step type with a domination of Artemisia. The pronounced climate and environment instability during the last phase of the Eemian Interglacial could be consistent with the assumption that it is a natural phenomenon, characteristic for transitional stages. Taking into consideration that the currently observed global warming coincides with the natural cooling trend, the study of such transitional stages is important for understanding the underlying processes of the climate changes.