Antarctica had rainforests 50m years ago

Rainforests thrived in Antarctica during a period of high atmospheric carbon levels 50 million years ago, scientists have discovered.

And they are warning the planet’s atmosphere could have similar levels of the greenhouse gas within hundreds of years.

An international team led by German scientists and involving University of Queensland Environmental Geologist Dr Kevin Welsh has found tropical palms grew on the coast of Antarctica 52 million years ago.

At that warm period in the earth’s history, there was twice as much CO2 in the atmosphere as there is now and winter temperatures of 10C meant Antarctica’s 4km thick ice sheet didn’t exist.

“It’s massively different to what we think of today,” Dr Welsh told AAP.

“It would be entirely ice-free and not only ice-free but warm enough that you’d have near-tropical rainforest actually growing along the margin of the continent.”

Dr Welsh was on board the JOIDES Resolution as it drilled the seabed off the coast of Antarctica in early 2010 as part of the multi-national Integrated Ocean Drilling Program.

The seabed cores brought to the surface are like a trip back in time for scientists, who can find evidence of temperature and ecology over millions of years.

They remain unsure why CO2 was so high 50 million years ago, but they say humans are on track to produce similar levels within centuries.

“If the current CO2 emissions continue unabated due to the burning of fossil fuels, CO2 concentrations in the atmosphere, as they existed in the distant past, are likely to be achieved within a few hundred years,” said Professor Jorg Pross, lead author of a paper published in the journal Nature.

A bushwalk in Antarctica for our descendants remains unlikely because additional factors such as warm currents also contributed to the prehistoric warm period.

But changes are expected.

“We could end up with an ice-free Antarctica,” Dr Welsh said.

“Even melting small amounts of ice from Antarctica has quite significant implications for sea level.”

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