Mesozoic Climate
Why were there dinosaurs
in Antarctica?
In 1991, researchers found the bones of a six-meter carnivorous dinosaur in Antarctica. The answer to what it was doing there explains the entire Mesozoic world.
In 1991, researchers found the bones of a carnivorous dinosaur in Antarctica with a curious bony crest on its skull. They named the creature Cryolophosaurus elliotti. It was about six meters long, lived 190 million years ago, and inhabited a region that today is covered in ice year-round.
The reason is simple: during the Jurassic, the planet was radically warmer than today. Atmospheric CO₂ ranged between 1,500 and 3,000 parts per million, compared to roughly 420 ppm today. This intense greenhouse effect kept the poles at temperatures comparable to present-day southern France, even in winter. There were no permanent polar ice caps.
There was another geographic factor: Antarctica was still part of Gondwana, the southern supercontinent. It was connected to South America and Australia by land bridges, which allowed dinosaur populations to migrate between continents over millions of years.
The real challenge of living at the Jurassic pole was the months of total darkness in winter, not the cold. Some dinosaurs probably migrated to lower latitudes in autumn. Others, like smaller herbivores, may have stayed and survived on fat reserves, much like many high-latitude birds do today.
Climate comparison
Known polar dinosaurs
Cryolophosaurus elliotti
Antarctica, ~190 Ma. 6 m carnivore with a unique cranial crest, the most famous Antarctic dinosaur.
Glacialisaurus hammeri
Antarctica, ~190 Ma. Herbivorous sauropodomorph found in the same formation as Cryolophosaurus.
Leaellynasaura amicagraphica
Australia, ~105 Ma. The continent sat at the south pole during the Cretaceous. Large eyes, possibly adapted to polar darkness.
Edmontosaurus annectens
Alaska, ~69 Ma. Hadrosaur that lived in the Arctic Circle and likely migrated seasonally.
Why was the planet so hot?
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Intense volcanism
The breakup of Pangaea activated large igneous provinces, episodes of massive volcanism that lasted hundreds of thousands to millions of years. These eruptions released CO₂ continuously, and without enough vegetation to absorb the excess, it accumulated in the atmosphere.
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Shallow, warm oceans
Sea level was about 200 meters higher than today, covering large portions of the continents. More shallow ocean meant more evaporation, more water vapor in the atmosphere, and more heat retention.
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No ice-albedo feedback
Today, polar ice caps reflect sunlight back into space, cooling the planet. In the Mesozoic, without this albedo feedback, any temperature increase was amplified. The climate system was locked in hot mode.