The Middle Miocene Climate Transition
In under a million years the world steps down into the cold state it has stayed in ever since.
- When
- —
- Duration
- 900 thousand years
- Known to
- ± 200 thousand years
- Era
- Miocene, Cenozoic
Between roughly 14.7 and 13.8 million years ago the East Antarctic Ice Sheet expands sharply and permanently, deep water cools by several degrees, and the latitudinal temperature gradient steepens. Antarctica's last tundra dies and the continent becomes the polar desert it remains. Falling carbon dioxide is the primary driver, with orbital configuration setting the timing. It is the second of the three great Cenozoic cooling steps, after the Eocene-Oligocene transition and before Northern Hemisphere glaciation.