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.