Life on the Earth exists thanks to a happy coincidence, a series of super volcanic eruptions, melt about 570 million years ago a giant ice sheet that covered the entire planet, according to a paper published in the journal Nature Geoscience.
“In order to reconstruct the full history of the Earth at that time, we had to perform a huge number of crystals of zircon, formed in different geological epochs. This allowed us to find the most powerful greenhouse gases in Earth’s history, which occurred just before the Cambrian explosion, the most important event in the evolution of life on Earth,” said Chad Deering (Chad Deering) from the University of Michigan in Houghton (USA).
The Earth’s atmosphere before the first plants and microbes is almost entirely composed of nitrogen, carbon dioxide, methane and other greenhouse gases. Oxygen it began to appear only about 2.2 billion years ago, after the so-called “great oxygen catastrophe”, when the first photosynthetic microbes began to absorb atmospheric CO2 and saturate it with oxygen.
As a result, the strength of the greenhouse effect weakened, and, as scientists believe today, approximately 850-600 million years ago the Earth turned into a kind of “snowball” – the temperature on earth has declined so much that its oceans began to freeze to the equator. How the Earth got out of this glaciation, scientists still argue.