A most recent inquiry into climatic change during the ice age and it's possibility of reoccurring is the Snowball Earth Hypothesis advanced by Paul Hoffman of Harvard University. Snowball Earth Suggest that before the Ice age, continents ice free at the poles enhanced the reabsorption of carbon dioxide through erosion of silicate minerals, reducing the greenhouse effect making the earth colder until it reached a runaway point. This effect is Hoffman calls albedo, when the atmosphere becomes so cold it can never warm up again. This is what occurred during the ice age, until volcano activity saturated the atmosphere with carbon dioxide to a point that it trapped radiation from the Sun and rewarmed the climate causing glacial thaw. Evidence of this event is cap carbonates that show relative dating at the ice age, found in abundance in several different world regions, at certain levels the cap carbonates would indicate if carbon dioxide was emitted into the atmosphere, by showing carbon levels that would demonstrate how much photosynthesis was occurring. Iron rich rock deposits indicate that absents of oxcidation would mean the atmosphere contain no oxygen, without oxygen their is no life, therefore other evidence of total extinction. So experts dispute the oceans were encased beneath a kilometer thick sheet of ice sheet, or that all life became extinct. The evidence of the Snowball effect is challenged that levels of carbon had not reached those required to satisfy the model and that alternative models are possible to explain the arrival and conclusion of the ice age. Iron had not oxidized because the glacials prevented contact with the atmosphere that would of subjected these rocks to mechanical weathering.
The Snowball Earth Hypothesis bases its theory on an invalid model of earth at that time. Ancient earth of the Proterozoic 750 million years ago existed in a separate dimension then what the model is based upon. There wasn't much of an ocean completely...
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