Snowball Earth


Snowball Earth describes a theory that for millions of years the Earth was entirely smothered 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.


Snowball Earth may inadvertently have accelerated evolution by reducing competition and thus have allowed the Cambrian Explosion to occur below the ice.


Miracle Planet : Snowball Earth

This video explores some of the first creatures to have emerged, that were larger and more complex than microbes and had a certain autonomy.