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A sensational discovery has determined that a rainforest once existed on Antarctica, suggesting the continent had a vastly different climate at one point.
While Antarctica is now a land of ice and snow, 90m years ago the continent had a very different look. That’s according to new research from a team of scientists that uncovered evidence of an ancient rainforest on the western side of Antarctica.
With researchers from Imperial College London (ICL) and the Alfred Wegener Institute Helmholtz Centre for Polar and Marine Research, the team found preserved roots, pollen and spores approximately 900km from the south pole. A study on the findings has been published to Nature.
Tina van de Flierdt of ICL said that this is an “exceptional” discovery, adding that “even more surprising is the world it reveals”.
“Even during months of darkness, swampy temperate rainforests were able to grow close to the south pole, revealing an even warmer climate than we expected,” she said.
The team’s findings also showed CO2 levels during the mid-Cretaceous period – between 115m and 80m years ago – were higher than expected. This challenges established climate models of the period, which was not only the heyday of dinosaurs but also the warmest period in the past 140m years.
Map of the drill site and how the continents were arranged 90m years ago. Image: Alfred Wegener Institute
Four months of polar night
At the tropics, temperatures would have reached as high as 35 degrees Celsius with sea levels being 170 metres higher than they are today. However, until now, little was known of what Antarctica was like during this time.
The rainforest that once existed on Antarctica would be similar to that found in New Zealand today. This is despite a four-month polar night, meaning for a third of every year there was no life-giving sunlight at all.
Samples suggest the average temperature of the forest would have been around 12 degrees Celsius and there would likely not have been an ice cap at the south pole at the time. Average summer temperatures were around 19 degrees Celsius, with rivers and swamps reaching water temperatures of up to 20 degrees Celsius.
Lead author of the study, Dr Johann Klages, said: “Before our study, the general assumption was that the global CO2 concentration in the Cretaceous was roughly 1000 parts per million (ppm).
“But in our model-based experiments, it took concentration levels of 1120 to 1680ppm to reach the average temperatures back then in the Antarctic.”
