The Huronian glaciation
Earth freezes for over 200 million years — the longest ice age in its history.
- When
- —
- Duration
- 230 million years
- Known to
- ± 50 million years
- Era
- Paleoproterozoic, Proterozoic
Beginning around 2.45 billion years ago, at least three and possibly four glacial episodes grip the planet, running to roughly 2.22 Ga. Glacial deposits appear at low latitudes, suggesting ice reached the tropics. The cause is almost certainly the rise of oxygen: free oxygen destroyed the atmospheric methane that had been keeping a dim-Sun Earth warm, and the greenhouse collapsed. It is the first time life demonstrably changed the climate of the whole planet.