Our Earth has already lived through several ice ages, during which the oceans were covered with ice all the way down to the equator – so-called Snowball eras. Life on our planet has survived all these times; primarily due to one reason: at the time, life existed only in the oceans, and the depths of the oceans still offered good conditions for life. What would have happened if life had already made its way onto land? That was the basis of a study done by Canadian researchers.
Snowball Earths result basically when the percentage of carbon dioxide (CO2) in the atmosphere decreases too much. Right now, we have the opposite problem, but in our Earth’s past (and this also happens on other planets), the atmosphere’s CO2 content has decreased, when heavy rainfalls coincided with erosion. Rainwater absorbs CO2 and then falls to the surface, where it reacts with rock to form carbonates. Bound in these rocks, the CO2 is eventually deposited onto the bottom of the ocean.