When dinosaurs roamed the planet, Antarctica was home to "dense temperate, swampy forest, similar to the forests found in New Zealand today", scientists have discovered.
The "unexpected fossil traces" of the temperate forest were found in a core sediment dug up near West Antarctica’s Pine Island Glacier back in 2017, according to UK and German scientists.
"The unusual colouration of the sediment layer quickly caught our attention; it clearly differed from the layers above it," said Johann Klages, a geologist at the Alfred Wegener Institute Helmholtz Centre for Polar and Marine Research in Germany.
CT scans found "a fascinating dense network of roots spreading through the entire soil layer" dating back 90 million years - during the Cretaceous period, when dinosaurs ruled the Earth.
The well-preserved core contained "countless traces of pollen, spores, remnants of flowering plants, and the researchers could even make out individual cell structures", according to a release by the UK's Northumbria University.
"It was particularly fascinating to see the well-preserved diverse fossil pollen and other plant remains in a sediment deposited some 90 million years ago, near the South Pole," said study co-author Ulrich Salzmann.
"The numerous plant remains indicate that the coast of West Antarctica was, back then, a dense temperate, swampy forest, similar to the forests found in New Zealand today."
Rainfall would have been similar to another rugby-loving country: Wales.
Further analysis suggested the average temperature in that part of Antarctica at the time was about 12C - a temperature most Kiwis would find comfortable. In summer it averaged a balmy 19C, despite the nights being four months long, and 20C in ancient Antarctic rivers and swamps.
This is much warmer than had previously been assumed, but there's simply no other way to account for the presence of a rainforest in Antarctica.
"Before our study, the general assumption was that the global carbon dioxide concentration in the Cretaceous was roughly 1000 parts per million," said climate modeller Gerrit Lohmann of the Alfred Wegener Institute in Germany.
But to achieve such conditions, the scientists calculated atmosphere carbon concentration must have been between 1120 and 1680 parts per million - three to four times what they are today.
"As such, the study shows both the enormous potency of the greenhouse gas carbon dioxide, and how essential the cooling effects of today’s ice sheets are," Northumbria University said.