About 700m years ago, the Earth froze over entirely – now we may know why | Climate science

IIt is difficult to believe, but about 700 meters ago, we think that our planet was completely freezing with little or no ocean or liquid lakes exposed to the atmosphere, even in the tropics. But what is the climate of the earth in the state of “snowball land”? A new study suggests a cold climate and massive volcanic eruptions began.

Franklin’s eruptions – About 720 meters ago – spit large amounts of fresh rocks, extending from what is now Alaska, from northern Canada to Greenland. Likewise, large eruptions have occurred at other times, but it coincides with an already cold climate. And combined with a lack of plants (they had not yet evolved), these eruptions have exposed a huge carpet of fresh rock to intense alteration.

The chemical reactions associated with alteration remove carbon dioxide from air. By modeling the climate impact, the researchers showed that rapid erosion on such a large area could have lowered enough carbon dioxide to switch the earth in a snowball state. The results, which are published in the Journal of Geophysical Research: Planets, also show that volcanic eruptions of size similar to other moments in the history of the earth have not generated snowball conditions because they occurred when the background climate was warmer, or sometimes when the coverage of vegetation slowed down the erosion rate.