Drilling of the seabed off Antarctica has revealed evidence of a rainforest that once flourished on the continent some 52 million years ago.

Scientists studying sediment cores discovered fossilized pollen that could only have come from a “near-tropical” forest covering the continent in the Eocene period, 34-56 million years ago. According to Australian scientist Kevin Walsh, analysis of “temperature-sensitive molecules” contained in the pollen showed the average temperature be near 68 degrees F.

There were forests existing on the land, there wouldn’t have been any ice, it would have been very warm,” Welsh told AFP of the study, published in the journal Nature. ”It’s quite surprising, because obviously our image of Antarctica is that it’s very cold and full of ice.”

Today, the average temperature of Antarctica is roughly -58 degrees F. Scientists say that during the Eocene period, even with polar darkness, the Antarctica region remained frost-free.

During this warm period, estimates are that carbon dioxide levels reached between 992 to a couple thousand parts per million in Antarctica. CO2 levels today are estimated to be at about 395 ppm on the continent.

“Our work carries a sobering message,” Dr James Bendle, one of the authors of the study, told The Independent. “Carbon dioxide levels are rising rapidly through human combustion of fossil fuels and deforestation.

“Atmospherically speaking we are heading rapidly back in time towards the Eocene.”

The authors concluded that, without drastic changes,  carbon dioxide levels in the atmosphere last seen during the Eocene could be reached again in only a few hundred years.

“We haven’t reached Eocene levels yet but we are increasing at a rate faster than any time in Earth’s history,” said Bendle.

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