Evidence That Antarctica Was Once Warm

Multiple lines of proof show Antarctica had temperate climates in the past:

• Coal Deposits: Formed from ancient swamp forests (Permian/Triassic).
• Plant Fossils: Ferns, cycads, Glossopteris (seed ferns) in sedimentary rocks.
• Dinosaur Fossils: Cryolophosaurus, Antarctopelta—require ice-free land.
• Paleomagnetism & Plate Tectonics: Antarctica drifted from equatorial latitudes to the South Pole over millions of years.
• Ice Core Isotopes: Oxygen-18 ratios indicate warmer periods (e.g., Eocene, ~50 Ma).
• Sea-Level Records: High Cretaceous seas imply minimal ice sheets.
• Climate Models: Simulations match proxy data showing warm, vegetated Antarctica.

Antarctica froze over ~34 million years ago (Oligocene) as CO₂ dropped and the Antarctic Circumpolar Current formed.