Two ideas exist on the progression of glaciation on Earth from 716.5 to 630 million years ago. Current evidence suggests the top version: a dynamic snowball Earth in which at least two long-lived glaciations happened during which communication between the ocean and the atmosphere was cut off. In this scenario, as CO2 built up, a hot-house effect ensued resulting in an ice-free planet at 670 and 630 million years ago. Credit: Zina Deretsky, National Science Foundation
From Live Science:
Sea ice may have covered the Earth's surface all the way to the equator hundreds of millions of years ago, a new study finds, adding more evidence to the theory that a "snowball Earth" once existed.
The finding, detailed in the March 5 issue of the journal Science, also has implications for the survival and evolution of life on Earth through this bitter ice age.
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