Antarctica was once home to a warm rainforest dominated by palms and trees, and a mountain forest with beech and conifer trees.
An international team of researchers have been studying this past landscape in order to understand current climate anthropogenic global warming. They bored 1km into the ocean floor at Wilkes Land – under 4km of water – to collect samples of sediment to reveal the Earth’s climate during the ‘Greenhouse world’ of the early Eocene epoch.
Analysis disclosed a detailed picture of the climate during the peak of the Eocene period – 48 to 55 million years ago – as researchers found fossilised pollen from plants that live in two different environments. One was a lowland, warm rainforest dominated by tree-ferns, palms and trees from the bombacaceae family; the other an upland forest region dominated by conifers and beech trees.
“The Eocene sediment samples are the first detailed evidence we have of what was happening on the Antarctic during this vitally important time,” said Dr James Bendle from the University of Glasgow.
“We conducted the drilling expedition against a backdrop of freezing temperatures, huge ocean swells, calving glaciers, snow-covered mountains and icebergs. It’s amazing to imagine a time-traveller, arriving at the same coastline in the early Eocene, could paddle in pleasantly warm waters lapping at a lush forest.”
Analysis of the pollen – preserved in the shallow coastal shelf for last 50 million years – indicate temperatures on the Antarctic coast were around 16°C, reaching 21°C in summer and 10°C in winter, even in the coldest darkest months.
The research – published in Nature – provides important insights into how the planet could look in the future if climate change continues at the current pace.
“By understanding naturally occurring climate warming periods in the geological past, our knowledge of the mechanisms and processes in the climate system increases,” said lead author, Professor Jörg Pross from Goethe University. “This contributes enormously to improving our understanding of current human-induced global warming.”
Researchers believe if current CO2 levels continue unchecked, we could reach Eocene levels in a few hundred years.
“Our work carries a sobering message,” said Bendle. “Carbon dioxide levels were naturally high in the early Eocene, but today CO2 levels are rising rapidly.”