About 700 million years ago, Earth was entombed in a veneer of ice hundreds of feet thick—a frozen state scientists refer to ...

Our species likes it cold. Homo sapiens evolved in — and still inhabits — one of Earth’s rare and fragile ice ages, periods distinguished not by an abundance of saber-toothed cats and woolly mammoths ...

This video examines a moment in Earth’s history when environmental change occurred far faster than expected. Geological and fossil records are compared to show how temperature, carbon levels, and life ...