What the Pliocene epoch can teach us about future warming on Earth

About 3 million years ago, carbon dioxide levels were similar to today’s. What other changes might we expect?

illustration of life in the Pliocene

BLAST FROM THE PAST  Three million years ago, Earth’s climate was so warm that the High Arctic supported forests (illustrated) in which camels and other animals roamed.

Julius T. Csotonyi

Imagine a world where the polar ice sheets are melting, sea level is rising and the atmosphere is stuffed with about 400 parts per million of carbon dioxide.