Arctic forests and climate in the Eocene greenhouse world 50 million years ago: Results from WUN pACE team

Category Climate system
Group GSI.IR
Location International Geological Congress,oslo 2008
Author Francis, Jane; Poulter, Jonathan
Holding Date 06 October 2008

Fifty million years ago during the Eocene the climate was globally warm with atmospheric CO2 levels much like those predicted for our future warm world. Polar regions were free of permanent ice caps but instead were covered by forest vegetation, now preserved in the rock record as fossil plants. In the northern high latitudes in the Canadian Arctic broad-leaved deciduous forests were dominated by the deciduous conifer dawn redwood (Metasequoia) along with pines, spruce and larch. Flowering trees such as alder, birch, and hickory were also present, along with ginkgo and katsura. On Svalbard a fossil flora dominated by large birch leaves has been recovered, including also Metasequoia and the flowering tree katsura (Cercidiphyllum). Climate signals in fossils and sediments indicate that this polar region experienced summers with relatively high temperatures (~24 °C) and winter temperatures that remained relatively mild. By comparison, floras in Antarctica indicate that while summers were as warm, temperatures below freezing may have occurred during the winters. The plant record indicates that climate cooling occurred earlier in southern high latitudes than in the north, but it was only when summer temperatures were cold enough for winter ice to persist all year that permanent ice caps were established.