Dinosaurs thrived in colder climates, as exemplified by the feathered dinosaur Beipiaosaurus, which lived between 127 and 121 million years ago.
Mark P. Whitton/Science Photo Library
About 200 million years ago, the North Pole was occupied by a massive landmass, three times the size of the South Pole. This land triggered a prolonged cold spell, allowing dinosaurs to dominate the Earth.
Paleontologist Paul Olsen from Columbia University explains how this “gigantic Arctic continent” encompassed present-day Siberia and parts of China.
During much of the Mesozoic Era, which extended from 252 million to 66 million years ago, nearly all of Earth’s land, except modern-day China, merged into the supercontinent Pangea. This vast landmass later fragmented into two entities surrounded by the only ocean at the time, Panthalassa.
Olsen and fellow researchers have concluded that new geological analyses, including magnetic rock signatures, reveal the ancient latitudes of these formations, linking Mesozoic China back to Pangea. The positioning of continents suggests Siberia and China once formed a significant portion of the Arctic Circle.
Olsen plans to discuss these findings at the upcoming European Geosciences Union meeting in Vienna next month, illuminating how this climate-centric puzzle comes together.
The Mesozoic climate was markedly warmer than today. However, 201 million years ago, during the late Triassic epoch, Pangea began to disassemble, leading to the formation of the Atlantic Ocean. The subsequent volcanic activity coincided with global cooling, lowering sea levels, prompting extinction events, and allowing dinosaurs to rise.
Olsen theorizes that the Arctic’s influence was pivotal. Even in a temperate climate, the vast landmass near the North Pole would experience winter snow and ice. These icy regions possess a high albedo effect, meaning a significant portion of solar energy is reflected away, contributing to cold conditions.
Left: Antarctica today; Right: The Arctic continent that existed 200 million years ago
Paul Olsen et al. 2026
Volcanic activity released aerosols into the atmosphere, contributing to a cooling climate that hindered summer melting in the northern regions. This preserved ice, maintaining high albedo levels and extending cold temperatures, possibly allowing polar ice sheets to persist for thousands of years.
The increase in Arctic ice contributed to falling sea levels, while extreme cooling from volcanic winters led to mass extinctions. Some resilient dinosaurs adapting to cold climates evolved insulating feathers, helping them survive severe winters and emerge as dominant species once global temperatures stabilized.
“This hypothesis is surprising because we traditionally view the Mesozoic era as ice-free,” says Mike Benton of the University of Bristol. “Imagining early dinosaurs navigating a harsh winter landscape is innovative, even if short-lived. During this period of high extinction, volcanic eruptions combined with polar ice may have disrupted dinosaur populations significantly.”
Olsen further emphasizes that the existence of a large Arctic continent has been “hidden in plain sight.” He notes, “Many depictions of Earth visually distort polar regions, obscuring their importance in geological history.”
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Source: www.newscientist.com

