Snowball Earth might have had a dynamic climate and open seas

Over 600 million years ago, most of Earth completely froze over, becoming “Snowball Earth.” But even during this frigid period, the climate still behaved in familiar ways, earth scientist Chloe Griffin and colleagues report in the April 1 Earth and Planetary Science Letters. There even seems to have been a tropical climate cycle, like modern El Niños and La Niñas.

“Everyone thought that the climate system would be really quite stable due to global ice coverage,” says Griffin, of the University of Southampton in England. Instead, she and her colleagues found evidence of an active climate and a partially open ocean.