Last time CO2 levels were this high, there were trees at the South Pole - Using sedimentary records and plant fossils, researchers have found that temperatures near the South Pole were about 20C higher than now in the Pliocene epoch, from 5.3m to 2.6m years ago.

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Last time CO2 levels were this high, there were trees at the South Pole - Using sedimentary records and plant fossils, researchers have found that temperatures near the South Pole were about 20C higher than now in the Pliocene epoch, from 5.3m to 2.6m years ago.