The isotopic climatic records in the Alleröd‐Bølling‐Younger Dryas and Post‐Younger Dryas events

Abstract

The combined isotopic records in the Greenland ice cores, in modern and ancient wood samples, and in marine foraminifera provide a climatic record for the Alleröd‐Bølling‐Younger Dryas and post‐Younger Dryas Periods that is not compatible with the usual climatic interpretation of the 2H/1H ratios in the Greenland ice cores. For example, the Younger Dryas was not solely a North Atlantic event because evidence for it is also found in the 2H/1H record in wood samples which grew on the north slope of Alaska. The Younger Dryas was not necessarily a time of cooling over the ice caps. Moreover, it might have been a warming period in the temperate zones of the northern hemisphere continents. A better understanding of the climatic scenarios during these periods of time could be ascertained from additional isotopic data in plant remains which grew during these intervals and which cover a wider climatic range on the continents.