Grains of Green

Pollen grains and leaf waxes record vegetation on Antarctica during a time of global warmth 20-15 million years ago, when greenhouse gas concentrations may have been similar to projections for the end of the 21st Century. The hydrogen isotopes in leaf waxes combined with model evidence reveal a rainy climate in stark contrast to the ice-covered margins of Antarctica under polar-desert conditions today. Pictured is a scanning electron micrograph of a southern beech pollen (Nothofagus fusca) collected from plants that grow today in New Zealand. This type of beech resembles the last stunted trees on Antarctica that disappeared from this region in the late Miocene epoch.

Image credit: Sophie Warny and Kate Griener (Louisiana State University, Baton Rouge)