Snowball Earth

Artwork showing Snowball Earth

Snowball Earth describes a theory that for millions of years the Earth was almost entirely or wholly covered in ice, stretching from the poles to the tropics.

This freezing happened over 650 million years ago in the Pre-Cambrian, though it's now thought that there may have been more than one of these global glaciations. They varied in duration and extent but during a full-on snowball event, life could only cling on in ice-free refuges, or where sunlight managed to penetrate through the ice to allow photosynthesis.

Image: Artwork depicting Snowball Earth (credit: Chris Butler/SPL)

Introduction

Artwork showing Snowball Earth Snowball Earth

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Snowball Earth

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