Until Now
EnvironmentBiology

Forests cool the planet

Trees pull down carbon dioxide so effectively that the greenhouse world begins to end.

When
Known to
± 15 million years
Era
Devonian, Paleozoic

Rooted forests accelerate silicate weathering and bury organic carbon on a scale nothing before could match. Atmospheric carbon dioxide falls by perhaps an order of magnitude through the Devonian, and the long greenhouse that had persisted since the Cambrian starts to break down. The cooling continues into the Carboniferous, culminating in a major ice age — driven, ultimately, by plants.

Just before

Just after