Surviving on 'Snowball Earth': Life Finds a Way.
Fossils of seaweed found in black shale in China's Hubei Province indicate that habitable marine environments were more widespread during the Cryogenian Period than previously known, when Earth twice froze over with runaway glaciation. The findings support the idea that it was more of a "Slushball Earth" where the earliest forms of complex life - basic multicellular organisms - endured even at mid-latitudes previously thought to have been frozen solid. The Cryogenian freeze was much worse than the most recent Ice Age that humans survived, ending roughly 10,000 years ago.