Palm trees grew on Antarctica 53 million years ago, CO2 likely 600+ppm, Nature study-BBC

8/1/12, "Palm trees 'grew on Antarctica'," BBC, Jason Palmer

"Scientists drilling deep into the edge of modern Antarctica have pulled up proof that palm trees once grew there.

Analyses of pollen and spores and the remains of tiny creatures have given a climatic picture of the early Eocene period, about 53 million years ago.

The study in Nature suggests Antarctic winter temperatures exceeded 10C, while summers may have reached 25C....

The early Eocene was a period of atmospheric CO2 concentrations higher than the current 390 parts per million (ppm )- reaching at least 600ppm and possibly far higher.

Global temperatures were on the order of 5C higher, and there was no sharp divide in temperature between the poles and the equator....

Drilling research carried out in recent years showed that the Arctic must have had a subtropical climate.

But the Antarctic presents a difficult challenge. Glaciation 34 million years ago wiped out much of the sediment that would give clues to past climate, and left kilometres of ice on top of what remains....

The lowland coastal region sported palm trees, while slightly inland, hills were populated with beech trees and conifers.

Dr Bendle said that as an analogue of modern Earth, the Eocene represents heightened levels of CO2 that will not be reached any time soon, and may not be reached at all if CO2 emissions abate."...

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