As we dip into August, we're inclined to imagine one last trip—chasing summer's sunny embrace to a lush clime in the Caribbean, the south of France, the Hawaiian archipelago, or... eastern Antarctica? Not this year, perhaps, but 55 million years ago, coastal Antarctica was a pretty balmy place. Summers peaked at about 25°C (77 F), winters were a mild 10°C (50 F), and the shores were filled with palm trees and ancestors of the modern macadamia and baobab. Warm ocean currents also contributed to the verdant landscape, so while palms and tree-ferns grew at the coast, the inland hills were populated with beech trees and conifers.
A recent article in Nature published the research and paleobotanical evidence, drawn from ice cores drilled from an offshore site near eastern Antarctica. Buried deep below the sea floor, the 55 million years-old sediment contained pollen and spores from temperate and "para-tropical" (warm weather) plants. They indicate that Antarctica's landscape was frost-free and botanically diverse. There were forests and gingkos.
Antarctica's paradise flourished from 55 million years ago through 48 mya, during the earliest Eocene era. It was a relatively short period (what's 10 million years in the grand scheme of the universe?) during which atmospheric carbon dioxide levels raised the average global temperature by 5°C. Forests replaced ice, Antarctica and Australia shared a coastline (the two continents were still connected at the surface), and carbon dioxide levels were as high as 1000 parts per million. Today's levels are about 390 ppm, so it's not as though this summer's hot weather trend is a harbinger of tropical Antarctic cruises. Yet.
Nonetheless, with carbon levels rising, scientists are increasingly looking to studies like this as an analogue of warming periods through geological trends. It helps to look at what happened then, when the temperature rose, to determine what will happen in the future, and to answer questions such as: If a palm-plenty Antarctic happened in the Eocene, is it possible in our era?
This palm frond fossil dating to the the Eocene period was found in Utah’s Green River Basin. Photo: USGS, via Smithsonian.
Anna Laurent is a writer and producer of educational botanical media.