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The Discovery of Global Warming                      September 2003

The tough little Dryas Octopetala ("Mountain Avens") will flower only in desolate tundra environments. Its durable pollen (a grain greatly enlarged, below) has long been used as a reliable indicator of arctic climate conditions many thousands of years ago.




Dryas photo: S. Weart, Devon Island, Nunavuk, Canada, 2005. Main page flower photo by Bob Skowron, courtesy Rocky Mountain Rare Plants. Pollen photo copyright K.D. Bennett, Uppsala University.
Page copyright © 2005 Spencer Weart and American Institute of Physics.